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RESOURCES AND WORKING DRAFTS ONLY

Contents

Freshwater fish of New Zealand[edit]

Map of the southern part of Zealandia, a "substantial ancient continent that is now evident as a series of emergent island, of which... New Zealand is much the largest, these and other smaller islands being connected by various submerged rises and plateaus".[1]
The New Zealand longfin eel is the largest freshwater eel in the world.

"Native freshwater fishes of New Zealand. The fauna is sparse (~ 40 species) and characterised by a high degree of diadromy... this fauna offered an opportunity to 'explore pattern and process, cause and effect, evolution and biogeography,in a way that would have been much more difficult in areas with more speciose faunas'... The family Galaxiidae comprises a group of southern hemisphere fishes whose wide geographic range and the diversity of habitats they have colonised are somewhat akin to the northern hemisphere salmonids... studying the ecology of the migrations of juvenile galaxiids (known locally as 'whitebait', and considered a delicacy)"[1]

"At present, 50 genetically distinct, extant fish species are recognised in freshwaters in New Zealand with another three or four species yet to be formally named (Allibone et al. 2010) (Table 1). However, the actual species number is hard to define because eight are classified as ‘freshwater indeterminate’: they are essentially marine species but move far into fresh waters for long periods. Only one native fish, the endemic grayling (Prototroctes oxyrhynchus), is known to have become extinct since the first human settlement of New Zealand c. 700 years ago, although many other species have become locally extinct over much of their pre-European range. New Zealand’s freshwater fish fauna is unique, with 92% of the named species found nowhere else in the world."[2]

"Diadromy: One feature of the New Zealand freshwater fish fauna is the large proportion of diadromous species: namely, fish that undertake two migratory movements between the ocean and fresh water in their life cycles. Diadromous fish employ three very distinctly different strategies: anadromy, catadromy, and amphidromy (Table 3). Anadromous fish spend their adult life in the sea, move to fresh water to breed, then die; catadromy is essentially the opposite, with fish spending most of their adult life in fresh water before a final migration to the ocean to breed and die; and amphidromy is an intermediate strategy in which adults live in fresh water, usually breed yearly, and the juveniles spend time in the ocean before returning to fresh water (McDowall 1988). A few decades ago diadromy was thought to be obligatory in most diadromous species, but we now know that in some species diadromy seems to be facultative, as not all individuals migrate. In the currently recognised extant taxa, diadromy is thought to be obligatory in 13 species and facultative in 6, and at least one diadromous species is present in each of the nine families in the New Zealand fauna (Ling 2010). Seven diadromous species include landlocked populations, usually, but not always, are formed when a lake outlet is blocked (Closs et al. 2003)"[3]

Overview[edit]

"Compared to other countries, New Zealand has a sparse freshwater fish fauna of just over fifty species. But it is unique and comprises at least thirty-five native species of which thirty-one are found only in New Zealand. Most of the native species belong to just four families of fish, and include twenty galaxiids, seven bullies, two eels, and two smelts. Nine potentially new galaxiid species have been recently found in Otago but are yet to be named so the list is not yet complete."[2]


"Because of the sparse native fish fauna, a large number of species have been introduced (legally, illegally and accidently). Of the fifteen species that are known to have established breeding populations in more than one location, six are salmonids (Salmonidae), four are cyprinids (cyprinidae), and three are live-bearers (Poecillidae). The redfin perch and the bullhead catfish are also well established. A further two species (grass and silver carp) are present, but do not breed. Five other species have very restricted populations and their current status is uncertain."[2]

"An unusually high proportion of the native fish are diadromous (i.e. they all have a marine phase in their lifecycle). Although several grow to adulthood in freshwater then migrate downriver to breed in the sea (e.g., eels, mullet, freshwater flounder), most breed in freshwater with their juveniles travelling downriver to develop at sea (e.g., galaxiids, smelt and bullies). Only the lamprey breeds and develops in freshwater streams and spends its entire adult life at sea."[2]

"Because these diadromous species all need to migrate upriver from the sea at some stage, they are vulnerable to barriers created by falls, chutes, dams, weirs, and culverts. They also vary widely in their ability to move upriver. Some species (eels and certain galaxiids) can climb vertical wet rock faces and they penetrate far upriver to high altitudes. Others cannot climb and are restricted to lowland, coastal streams. As a consequence, the geographical distributions of the species vary widely within rivers and are greatly affected by both altitude and distance from the sea."[2]

"Many of the native species are small, cryptic and/or are nocturnal so it is not surprising that most people are not aware that they are present. They express surprise when they learn that there is more to the native fauna than just eels and galaxiids. For example, redfin bullies are brightly coloured and good in aquaria, whereas torrent fish are shaped like a stealth fighter and are well adapted to cope with the high water velocities found in rapids where they live."[2]

"Many of the largest native galaxiids (called kokopu) live mostly in small streams running beneath forest or bush canopies. Widespread conversion of forest to pasture has resulted in their decline, and the introduction of predatory trout restricts their distributions within forested streams. As a consequence of these changes, together with the creation of migration barriers and loss of habitats, a number of the native fish are now endangered. A 2010 report indicated that whereas only the grayling is extinct, eight species are nationally threatened and another twelve are now in decline."[2]

"Eels and galaxiids are responsible for commercial and cultural fisheries in New Zealand rivers with five species of galaxiids comprising the national delicacy known as 'whitebait'. Sports fisheries are based on introduced species, including chinook salmon (South Island rivers), rainbow and brown trout (lakes and rivers nationally), and coarse fish (perch, rudd, tench, koi carp), mainly in small North Island lakes. Other introduced species (i.e., gambusia, catfish, goldfish) have few if any values and some of the introduced species are pests in some places because they either reduce native biodiversity, degrade other species habitats, or contribute to the decline of water quality in lakes."[2]

Native species[edit]

"The latest information indicates that New Zealand has around 40 native species of freshwater fish. This count may increase as new genetic techniques bring a better understanding of the diversity within some fish groups. Thirty-three species are known only in New Zealand. Kōaro, longfin eels and spotted eels are also found in Australia, while lamprey and īnanga also occur in Australia, Chile and Argentina. New Zealand’s native freshwater fish belong to eight distinct families: the jawless lamprey, eels, smelts, southern graylings, galaxiids, torrentfish, bullies and flounder. Most are relatively small, although the eels are an obvious exception – some female longfin eels are up to 2 metres long and 25 kilograms in weight."[3]

Age[edit]

"Longfin eels are the longest-living native fish, generally taking 20–30 years to reach maturity. Some large female eels stay in fresh water for over 80 years. In contrast, smaller species, such as īnanga, reach maturity in just one year and rarely live longer than three years."[3]

Diet[edit]

"Almost all native fish prey on invertebrates or other fish. However, historical accounts indicate that the now-extinct grayling (Prototroctes oxyrhynchus) was an exception and grazed on algae from river rocks."[3]

Migration and life cycles[edit]

"Nearly half the native fish species migrate to and from the sea during their life cycle. As not all species can climb rapids and waterfalls, freshwater fish are most diverse at low altitudes, closer to the coast.

  • Lampreys reproduce in fresh water but develop mostly at sea.
  • Eels reproduce at sea, but most of their growth occurs in fresh waters.
  • The five species of galaxiids that form the whitebait catch lay their eggs in fresh water, but their larvae quickly migrate to sea and spend a few months there before heading back to fresh water."[3]

Distribution[edit]

"Although not found elsewhere, many of New Zealand’s freshwater fish do have close relatives in Australia, South America and Southern Africa. Two species that do exist beyond New Zealand are lampreys and īnanga. This distribution, with other evidence, indicates that migration across the oceans is an important factor explaining the global spread of these fish."[3]

Factors affecting life in fresh water[edit]

"A range of factors influence the types of species that live in different parts of New Zealand.

  • At a broad level, evolutionary history and climate determine which species are found in certain regions.
  • At a finer level, factors such as water quality, land use, channel shape, or lake type influence the range of species found in a river reach or lake.
  • Small-scale factors (light and food availability, cover, predation, competition, water depth and speed) also control which species live at certain sites within a river or lake. All these factors can interact to shape freshwater ecosystems."[4]

Light availability[edit]

"Without light, plants cannot grow. There are big differences between the communities living in the well-lit surface and edges of lakes, and those in the depths, which receive little or no light. Turbid (muddy) water also restricts the amount of light that reaches the bed. Lakes with large shallow areas tend to be more productive than lakes with little shallow water (because more light reaches the lake bed). A similar situation exists in river systems, where heavily shaded streams rely on leaves and other organic material from the surrounding catchment to fuel the ecosystem. In larger rivers the canopy opens up, allowing algal production to become more important."[4]

Predators versus available food[edit]

"There is debate about whether the number of invertebrates (insects and other animals without backbones) in a habitat is controlled by the number of predators that will eat them, or by the amount of food available for them. Both factors are important, but their relative importance may vary. For example, the introduction of trout appears to have changed some streams from systems controlled by the available food to those controlled by trout as predators."[4]

Disturbances: floods and droughts[edit]

"Rivers and streams are particularly prone to disturbance, due to huge changes in flows, as in floods and droughts. Although these are often seen as harmful, it appears that a moderate level of disturbance can promote higher diversity in some systems. This makes sense: if there is some variation in an environment, more life forms may be able to live there."[4]

Human impact[edit]

"Irrigation and hydroelectricity projects. Water is currently in high demand, and the value of freshwater systems is often weighed against the potential value of using the water. Hydroelectric dams and large irrigation projects can turn running waters into lakes, affect water quality, and restrict fish movement along river systems."[4]

Farming[edit]

"Many rivers and lakes now have high concentrations of nutrients, sediment and faecal bacteria, and problems with algal blooms (a heavy growth of algae). This is because more intense farming leads to excessive runoff of sediment and fertilisers into waterways. Taking water for irrigation has also harmed the water quality of lowland streams and some lakes. The Rotorua lakes are classic examples. Too many nutrients enter the lakes, causing algal blooms, which in turn starve the water of oxygen. At times, the lakes are closed for swimming, due to low water quality."[4]

Pests[edit]

"Various pests have become established in freshwater systems. Pest fish prey on native species and can stir up mud and alter the water quality. Invasive aquatic plants grow profusely, changing the habitat and causing problems for recreational activities. For example the introduced weed Lagarosiphon major can grow so profusely that it clogs the shoreline, making it unattractive for swimming. Even tiny algae can cause problems. In 2004 outbreaks of Didymosphenia geminata smothered South Island riverbeds, affecting everything living there."[4]

Where are the fish?[edit]

"New Zealand has an abundance of cool clear rivers, streams and lakes, but if you look into the water you will not usually see many fish. The journals of many early settlers refer to empty rivers. Believing there were no native fish, they introduced trout and salmon – species that would meet their expectations as game and a source of food. But it was a mistake to think the rivers were empty, as Māori had long caught a wide variety of native fish. European settlers soon discovered the delight of fresh whitebait, and learned to fish for upokororo (grayling). As Māori knew well, eels were a nutritious addition, and livened up an often plain colonial diet. Many New Zealanders are surprised to learn that fisheries biologists recognise more than 40 native freshwater fish species. If asked about freshwater fish, most people will mention trout (which are not native), eels, and perhaps whitebait. There is little awareness of the variety of native fish in rivers and lakes."[5]

Ousted by trout[edit]

"New Zealanders are more familiar with trout and salmon than with native fish. Trout and salmon were introduced in the late 19th and early 20th centuries. Massive trout populations rapidly developed, with adverse effects on native fish through predation, competition for food and displacement from favoured habitats."[5]

Secretive and nocturnal[edit]

"For some reason that scientists do not understand, nearly all native freshwater fish are very furtive creatures. By day they typically live among boulders and pebbles of streams and lake beds, or hide beneath overhanging stream banks, or among logs and woody debris. Most species are also quite small. New Zealand’s eels are nocturnal, as are many other native freshwater fish. An effective, low-tech way of identifying fish, especially in small streams, is spotlighting – shining a broad-beamed torch into a stream at night to see what is out and about."[5]

Small streams[edit]

"The greatest diversity of native fish occurs in small streams – many of them no more than a metre wide. It is not clear why they prefer this habitat. It could be partly because introduced trout have forced them into smaller headwater streams, preying on them or displacing them from their habitats. It is likely that there are other reasons as well."[5]

Protection[edit]

"Freshwater fish are not protected under the Wildlife Act 1953, although native fish are protected in national parks or other conservation lands. For many species, legal protection from being caught is not really an issue as land use and developments that damage their habitats pose far greater threats to their survival. There are some regulations to manage the harvest of eels, whitebait, smelt and lamprey that form small fisheries."[5]

Evolution and characteristics[edit]

Geography[edit]

"New Zealand’s freshwater fish have strong connections with fish of other southern lands. The shortfin eel, īnanga and kōaro are found in eastern Australia, and īnanga in Patagonian South America and the Falkland Islands. In the past some researchers suggested that this spread was because New Zealand, like Australia, was once part of the supercontinent Gondwana. Recent DNA research indicates that it is far more likely that these fish are more recent arrivals, carried around the southern hemisphere on oceanic currents. Some endemic groups such as the pencil galaxias may have an ancient Gondwana heritage."[6]

Evolving from marine species[edit]

"Some species that evolved as marine fish have established themselves in fresh water. Just how this happens is unknown, but at some stage an event must have caused a shift into fresh water. Perhaps a lack of fish diversity in river rapids provided an opportunity for a marine species to invade this environment. The torrentfish still retains its marine connections by living at sea during larval and early juvenile life. The black flounder must still return to sea for spawning and early juvenile life. Several flounder (mainly marine) can also live in river estuaries and lowland lakes. But the black flounder has taken the process a little further – it may be found many kilometres up some rivers."[6]

Links to the sea[edit]

"Nearly half the native freshwater species are found in the sea at some life stage. This may be as larvae and juveniles (as with whitebait species and several bullies), after which they return to fresh water. Some adults (such as eels) may migrate to sea to spawn. In another example, the smelts living in rivers spend most of their lives at sea before returning to fresh water as adults, to spawn. Fish migrate between rivers and the sea at most times of the year, but especially in spring and autumn. These species are known as diadromous (from Greek words meaning ‘running across’)."[6]

Climbing[edit]

"The distribution of the migratory species depends on how far upstream they can move. Rapids and waterfalls are not necessarily barriers. Some species have extraordinary climbing abilities, and can be found upstream of waterfalls tens of metres high. Eels are able to climb like this, and some of the whitebait species, especially kōaro, banded kōkopu and shortjaw kōkopu. These fish climb mostly when small, moving up the wet margins of falls, and using their fins to hold onto rocks by surface adhesion. Some are well known for climbing out of buckets, and if in captivity, often climb out of aquariums (they can climb glass as long as it is damp)."[6]

Stuck in the Nevis[edit]

"For the past half million years Otago’s Nevis River has flowed north into the Kawarau River, which then flows into the Clutha River. But it is thought that the Nevis once flowed south, into Southland’s Mataura River. Supporting evidence is that the Nevis has a Galaxiid species (Galaxias gollumoides) that is otherwise found only in the Mataura and other Southland waterways. The fish is found only in one other isolated locality in the Clutha catchment."[6]

Flexible behaviour[edit]

"Many species can vary their behaviour. Although the ancestral pattern is for them to go to sea, they can establish landlocked populations in the open water of lakes rather than the sea – mostly at the juvenile stage."[6]

Nocturnal activity[edit]

"A high number of native species are nocturnal, moving from under cover to be active at night. Why they are so nocturnal is not understood. The most likely explanation is that it might minimise predation by aquatic birds, especially shags, and perhaps herons. But if it is an avoidance strategy then a paradox emerges. Some fish are habitual prey for large eels, which are also more active at night, emerging from cover to feed."[6]

Galaxiids[edit]

"Most native freshwater fish species are called galaxiids (from the family name Galaxiidae)... The name refers to their profusion of small, silvery-gold spots, which were compared to the stars in a galaxy by those who first identified them."[7]

"Most native freshwater fish species are called galaxiids (from the family name Galaxiidae). There are seven genera in the family and two (Galaxias and Neochanna) occur in New Zealand. The name refers to their profusion of small, silvery-gold spots, which were compared to the stars in a galaxy by those who first identified them... In New Zealand there are at least 25 species in this family. New species are still being discovered, with eight recognised since the early 1990s. Galaxiids are a fascinatingly diverse group. Most are shy creatures that few people ever see. A small number of enthusiasts find them appealing and keep them in captivity... Galaxiids have no scales, and their dorsal fin lies toward the rear of the body. The main fins form a propulsion unit towards the tail, making them adept at rapid acceleration and short bursts of speed, though not so well designed for long-distance swimming."[8]

"The galaxioid fishes are the dominant, most speciose group of freshwater fishes (with >50 species) in the lands of the cool southern hemisphere, with representatives in western and eastern Australia, Tasmania, New Caledonia, Lord Howe Island, New Zealand, the Chatham, Auckland and Campbell Islands, Patagonian South America (Chile, Argentina), the Falkland Islands and South Africa. The group is most diverse in Australia and New Zealand. Lepidogalaxiidae is found only in Australia, Retropinnidae in Australia and New Zealand, and Galaxiidae across the entire range of the group. Many species are in serious conservation crisis for a diversity of reasons, including habitat deterioration and possibly fisheries exploitation, but there is enduring and pervasive information that shows that the group has been seriously impacted by the acclimatisation of salmonid fishes originating in the cool-temperate northern hemisphere, particularly brown and rainbow trout. With few exceptions, where these trout have been introduced there has been major decline in the galaxioids, especially Galaxiidae, as a result of a complexly interacting series of adverse impacts from these introduced fishes. In some places, centrarchids and cichlids may also have adverse impacts. In addition, there appear to have been adverse impacts from the translocation of galaxioids into communities where they do not naturally occur. In many instances it appears that displacement of the galaxioids has led to a situation where galaxioids and salmonids no longer co-occur, owing either to displacement or predation, leading to fish communities in which there is no explicit evidence for displacement. These effects are resulting in the galaxioid fishes being amongst the most seriously threatened fishes known."[9]

Kōaro relatives[edit]

taxonomically uncertain

"There is a group of species that are closely related to the kōaro. Scientists are beginning to discover these highly secretive fish in the headwaters of streams in the eastern and southern South Island. Although very similar to the kōaro, they do not have larvae that go to sea. They spawn in spring. Over spring and summer small shoals of whitebait-like juveniles appear in pools and backwaters. They live in open water for several months and grow to about 4 centimetres long, when they disappear into gravels of stream beds and are rarely seen."[10]

Mudfish (Neochanna)[edit]

"Also belonging to the galaxiid family are the Neochanna mudfishes. These are specialised for living in wetlands and swampy spring heads. Best described as cigar-shaped, some may be up to 15 centimetres long. Of five species, three have completely lost their pelvic fins (fins under the body about halfway back to the tail), and in the others these are much reduced. Using their dorsal and anal fins, and well-adapted broad, rounded tails, they swim among the debris of bush wetlands. They are known for their ability to aestivate – spend summer in a state of semi-torpor, surviving if water disappears. Mudfish can survive a long drought. When their wetlands dry out in summer, they find cavities and objects to lie under, breathing air through their skin. As the autumn rains fill the wetlands, the fish are washed out again."[10]

Smelt[edit]

"New Zealand has two fish of the Retropinnidae family. These are the common smelt (Retropinna retropinna) and Stokell’s smelt (Stokellia anisodon). Although smelt have a very strong cucumber odour when they are first captured, the name smelt has nothing to do with this. It is an ancient word for silvery – referring to their colour. Growing to around 10 centimetres, smelt move into lowland rivers from the sea as mature adults to spawn – often being caught towards the end of the whitebait fishing season, in spring. They are very fragile, dying within a minute or two if handled. The smelt populations in some inland lakes, especially in the central North Island, belong to the same species, but have abandoned migrations to and from the sea, spending their whole lives in fresh water."[11]

Links[edit]

Conservation status[edit]

Resident native species (40)[edit]

Conservation status of New Zealand native freshwater fish species (sortable)
Family Image Scientific name Common name Fish-
base
IUCN status NZTCS status[12] Notes
Anguillidae
(eels)
Anguilla australis.jpg Anguilla australis Shortfin eel
Not assessed
1. Not Threatened
"The shortfin eel is quite widely distributed in the South Pacific, and occurs in Australia, New Caledonia, Lord Howe Island, Norfolk Island, Fiji and possibly Tahiti. Its dorsal fin starts close to the anal fin, and the pectoral fin has 14–16 rays. This eel is olive green and frequents lowland waterways. It can grow to 1 metre and 3.5 kilograms. Males mature, breed and die at 14 years, and females at 22."[14]

"Shortfin eels are one of the three Anguillidae species found in New Zealand. They differ from longfin eels in the length of their dorsal fin. In shortfin eels, the dorsal and anal fins are the same length so the ends are almost adjacent when the fish is viewed side-on. In longfin eels the dorsal fin is longer and extends well forward towards the head. Shortfin eels usually have a silvery belly compared to a yellowish one on longfins, but colours can vary considerably. Even pure yellow shortfin eels have been caught! Shortfin eels are found throughout New Zealand and on Chatham and Stewart Island. However, they are not unique to this country and also occur throughout the South Pacific – in Australia, New Caledonia, Norfolk and Lord Howe Island, and perhaps Fiji. Generally shortfin eels are found at lower elevations and not as far inland as longfin eels, but they are still able to climb large obstacles such as waterfalls when they are young. They are often very numerous in lowland lakes, wetlands, and streams, and shortfin eels form the basis of the commercial eel fishery that has existed for over 20 years in New Zealand. Shortfin eels are our most tolerant native fish species. They survive environmental hazards like high water temperatures or low dissolved oxygen concentrations. That means they can live in habitats where other species cannot survive. Their ability to live almost anywhere might explain why eels are so familiar to New Zealanders and why they were such an important food resource for Maori."[15]

NZ eel.jpg Anguilla dieffenbachii Longfin eel
Not assessed
2. At Risk
Declining
"The longfin eel is found only in New Zealand. Travelling far inland, it may be the country’s most widely distributed freshwater fish. The pectoral (side) fins have 16–20 bony rays. This species is usually dark brown to grey-black on the back. One study found that males swim out to sea to breed and die at an average age of 23 years and females at an average age of 34. They are probably the world’s biggest eels. They may grow up to 1.75 metres, and the biggest caught and measured so far weighed 24 kilograms. Any New Zealand eel over 1 metre long and caught inland is probably a longfin specimen."[14]

"Scientist Don Jellyman figured out the great age of some longfin eels in Lake Rotoiti – the oldest eels yet documented. He found that one female eel was 106 years old by reading the growth rings on its ear bones (otoliths). An average generation time of 93 years suggests that conservative harvest levels must be set in managing these fish. A New Zealand research team at the Mahurangi Technical Institute in Warkworth has hatched baby eels from eggs of the shortfin eel – the first time that commercial quantities of freshwater eel have been bred in captivity. The commercial and ecological implications of this breakthrough could be considerable. Tame eels have become a tourist attraction in places such as Tasman in Nelson and the Anatoki River in Golden Bay."[17]

"Longfin eels are distinguished from shortfin eels by the length of the dorsal fin; when viewed side-on, the dorsal fin is longer than the anal fin and extends well forward past the end of the anal fin. In shortfin eels, the dorsal and anal fin ends are almost the same length. Australian longfin eels can be distinguished from native longfins by the presence of irregular black blotches on the back and sides. Longfin eels are only found in New Zealand and occur throughout the country. The elvers are legendary climbers and penetrate well inland in most river systems, even those with natural barriers such as steep falls. Large hydroelectric dams can also be surmounted if appropriate facilities are provided for eel passage, or if elvers are caught at the base of the dam and stocked into the waters above it. Adults can move overland from one waterbody to another (e.g. from a river to an isolated farm pond) by crossing flat grassy land, especially when it is wet. The longfin eel occupies a wide range of habitats and occurs in rivers, streams, lakes ponds and wetlands. Longfin eels are carnivores and over about 40 cm in length they feed mostly on small fish and crustacea. They are responsible for major commercial and customary fisheries in New Zealand. Although the longfin eel is endemic and is one of our most common and largest freshwater fish, there is mounting concern at the scarcity of very large specimens which are being rapidly fished out, and longfin elvers are now becoming scarce as well. Pictures of huge eels used to appear regularly in local newspapers, but not any longer. Commercial harvesting is probably mostly to blame for the scarcity of large eels. These are generally females that contain huge numbers of eggs, and are thus important in sustaining the population. So, if you catch a big longfin – put it back in the water instead of feeding it to the cat!"[18]

Eleotridae
(bullies)
"After galaxiids, bullies form the second largest native fish family, known as Eleotridae. They are often called cockabullies, but these are a different family of mostly marine fish. Seven species are widespread across the country. Small fish seen around a lake shore will probably be bullies, most likely the species known as common bullies. Bullies are mostly small, with adults commonly around 10 centimetres long. They have scales and two dorsal fins. The redfin bully male has vivid red coloration, especially on the tail and dorsal and anal fins. These fish are found almost everywhere, although mostly at low elevations. This is partly because the young of four of the seven species spend their first few months at sea: the adults can be found only in places that are accessible from the sea. They have interesting breeding habits. The male establishes his territory, usually in a cavity beneath a large rock, and while guarding it, tends to turn a darker colour. The spawning female is lured into the territory and deposits the eggs, one by one, forming a single layer on the underside of a rock. The male, following along, fertilises them. He then guards them until they hatch.c[11]

"Members of the bully family occupy marine and fresh waters in the tropical Pacific and southeast Asia. There is just one freshwater genera in New Zealand, Gobiomorphus, with seven species...Bullies have rounded tails, two dorsal fins, a blunt head, and are quite stocky. They can sometimes be recognized by their habit of sitting on the substrate looking almost as if they were standing up on their forward fins. They have a darting method of swimming and usually remain on or close to the substrate. Amateurs will have difficulty distinguishing the bully species except for the bluegill and redfin bully, which have some obvious unique characteristics. Fish biologists have to rely on fin ray counts and scale patterns to correctly identify the species, and this usually requires examination of specimens under a microscope. Identification is complicated by the overlapping distribution of many of the species. Of the seven species of Gobiomorphus found in New Zealand, three are strictly diadromous (bluegill, redfin, and giant bullies), while three are non-diadromous (Crans, upland, and Tarndale bullies). The common bully can be either"[19]

Gobiomorphus alpinus Tarndale bully LC IUCN 3 1.svg Least concern[21]
2. At Risk
Declining
"Although the Tarndale bully is hard to visually distinguish from the other bully species, its location is a dead giveaway. Found in only a few small sub-alpine tarns in the headwaters of the Clarence and Wairau Rivers, it lives in splendid isolation in this remote region of Marlborough. The bully’s name comes from its location - that part of Molesworth Station formerly known as Tarndale Station."[22]
Gobiomorphus basalis Cran's bully LC IUCN 3 1.svg Least concern[24]
1. Not Threatened
"Crans bully is another non-diadromous member of the Eleotridae family. They are stocky little fish that are hard to distinguish from common and upland bullies, whose distributions overlap that of Crans bully. On mature males, the top edge of the first dorsal fin is a bright pinkish-orange, but this is not a useful identification characteristic for small bullies and females. Crans bully is strictly a North Island fish and is found in most areas. Its rarity in the arc northeast of Lake Taupo is thought to be a long-lasting effect of the Taupo eruption over 1800 years ago. As Crans bully has no marine phase, their ability to colonize new river systems is limited, and once they are gone from an area it is unlikely they will re-colonize on their own. With no requirement to go to the sea, Crans bully is most common at sites at mid altitudes and some distance inland. It dwells in stony rivers and streams and does not establish lake populations. Breeding behaviour is similar to the other bullies, with the male establishing a territory, and remaining to guard the eggs after they are laid."[25]
Gobiomorphus breviceps Upland bully LC IUCN 3 1.svg Least concern[27]
1. Not Threatened
"The upland bully is one of the non-diadromous members of the Eleotridae family. That means they live their whole lives in fresh water. Adult male upland bullies are relatively easy to identify - they have orange spots on their cheeks and head, and the outer edge of the dorsal fin is also orange. Immature fish and females are less easy to identify, particularly where their distribution overlaps with Crans bully in the lower North Island. Experts have to rely on pectoral fin ray counts under a microscope to ensure that upland bullies can be distinguishd from Crans bullies. Upland bullies are common along the east coast of the South Island. On the west coast, they occur in the Hokitika, Grey, and Buller River systems, but are absent from rivers north and south of there. It was recorded for the first time on Stewart Island in 1998. In the North Island, upland bullies are found from the Ruamahanga River catchment up to the Wanganui and Patea systems. They do not occur in the northern half of the North Island. Because upland bullies do not have to go to sea as part of their life cycle, they occur well inland in many river systems. But they are also found close to the coast. They will tolerate a variety of habitats, from stony-bedded rivers to weedy streams, and have even established populations in a few South Island lakes, e.g. Lake Coleridge. Like all the bully species, the males establish and defend territories during the breeding season. This accounts for their more dramatic colouration compared to the females. The eggs are laid in a primitive nest, which is usually the underside of a large rock. However, instream debris such as wood can also be used. After the eggs are laid, the male guards the nest from intruders and fans the eggs to keep them oxygenated. There is no parental care after hatching."[28]
Common bully, Gobiomorphus cotidianus.jpg Gobiomorphus cotidianus Common bully LC IUCN 3 1.svg Least concern[30]
1. Not Threatened
"There are three other bully species that are easily confused with common bullies, and identification is difficult without a microscope. Sometimes faint vertical lines along the cheek are a good characteristic, but this is not always reliable. The location of head pores and the scale pattern on the head are used to distinguish common bullies from Crans and upland bullies, whereas the number of spines in the first dorsal fin distinguishes common from giant bullies. Both of these characteristics are difficult to see in the field. The situation is further complicated by the wide overlap in the distribution of bully species. Common bullies are everywhere in New Zealand. Sea-going populations occur in river and streams near the coast, and land-locked populations have become established in many of our lakes where they are an important prey species for trout and eels. In rivers, they mainly inhabit still or slow-flowing waters and thus are probably one of the most likely bullies to be seen. In lakes, the larvae are planktonic and feed on zooplankton. Eggs are laid on the undersides of hard substrates (wood, rock) in both lakes and rivers, and the egg patches are defended by a male. Apart from a few records from Stewart and Great Barrier Island, common bullies are largely confined to the mainland in New Zealand. Like all the bully species, common bullies are unique to New Zealand. Common bully can grow to a large size; specimens over 120 mm are not unusual."[31]
Giant bully, Gobiomorphus gobioides.jpg Gobiomorphus gobioides Giant bully LC IUCN 3 1.svg Least concern[33]
1. Not Threatened
"As its name implies, the giant bully is the largest member of the Eleotridae family in New Zealand. Specimens of over 250 mm in length have been reported, although fish in the 120-150 mm range are more common. It is virtually impossible to distinguish the giant bully from the common bully unless you count the number of spines in the first dorsal fin. In giant bullies there are always six spines and in common bully there are usually seven. However, these are difficult to count in the field unless you have some forceps because the spines tend to collapse when the fish is out of the water. Size alone is not a good indicator because common bullies can also grow to 150 mm. The life cycle of giant bullies is somewhat of a mystery. The larvae are thought to have a marine phase, but no juvenile giant bullies have ever been positively identified. In fact, few giant bullies of less than 80 mm have been recorded. Whether small giant bullies have not been distinguished from common bullies or whether they live elsewhere is not known. The adults are never found more then a few kilometres inland and it is possible that they may spend a long period in estuaries before moving into fresh water. Giant bullies have been found in most regions in New Zealand. The slow flowing coastal habitats they live in are difficult to sample although bullies will readily enter fyke nets and traps. To date there have been no studies of this fish so there is no knowledge of its ecological requirements and role"[34]
Gobiomorphus hubbsi Bluegill bully VU IUCN 3 1.svg Vulnerable[36]
2. At Risk
Declining
"The bright blue gill cover just behind the head readily distinguishes the aptly named bluegill bully from other members of the Eleotridiae family. Small dark spots that cover their cheeks are another useful characteristic. When viewed from the top bluegill bullies are arrow shaped, with their narrow elongate body trailing behind the larger head. Bluegill bullies inhabit similar habitat to torrentfish - swift broken water in open rivers and streams. They also have a similar distribution pattern to torrentfish, being absent from Fiordland, Stewart and Chatham Island, and rare in Otago and Southland. Overall, they are not as common as torrentfish, particularly in Taranaki and Coromandel. Bluegill bullies are the smallest members of the Eleotridiae family in New Zealand. The largest specimen recorded is a 100 mm bully, but most adults are between 60–70 mm in length. In common with all the bully species, bluegill bullies are benthic. Bluegill bullies are strictly carnivorous, and their food is mainly mayfly larvae. Males grow larger than the females and the larger fish (both sexes) are found further upstream than the smaller ones."[37]
Male redfin bully (Gobiomorphus huttoni).jpg Gobiomorphus huttoni Redfin bully NT IUCN 3 1.svg Near threatened[39]
2. At Risk
Declining
"The bright red fins of an adult male redfin have to make this one of New Zealand's most attractive freshwater fish. Although only males get this distinct colouration, the diagonal stripes on the cheeks make the redfin bully easy to identify. These stripes are even visible in small bullies from about 30 mm in length. Redfin bullies are strictly diadromous and do not establish land-locked populations. Thus, they tend to live near the coast even though they are very good climbers (populations above 5-m-high waterfalls have been recorded). Spawning takes place in fresh water and after hatching the larvae are swept out to sea. The juveniles enter fresh water in the spring and reach maturity about two years later. This diadromous habit means that they are widespread throughout the country and have been frequently recorded from Chatham and Stewart Islands. However, they are rare along the east coast of the South Island above Oamaru, except for Banks Peninsula. Redfin bullies occur mainly in the runs and pools of small bouldery streams and their principal food is mayfly, caddis fly and chironomid larvae. Becuase of their dependance on this habitat, they are more sensitive to the effects of siltation in streams than other fish species. The redfin bully was recognized as a distinct species as early as 1894, but it has had many name changes over the years. The present specific name huttoni honours one of New Zealand's early biologists, Sir Frederick W. Hutton, who was a director of the Canterbury Museum from 1892 to 1905."[40]
Galaxiidae Galaxias anomalus Roundhead galaxias CR IUCN 3 1.svg Critically endangered[42]
4. Threatened
Nationally Endangered
"The roundhead galaxias is another non-diadromous member of the Galaxiidae family that is found only in Otago. It occurs in the Taieri and Clutha catchments, although there is still some uncertainty about the records in the Pomahaka. The map shows our best knowledge of its distribution to date and the description below refers to the Taieri roundhead galaxias. The number of caudal fin rays can be used to distinguish the roundhead galaxias (16 fin rays) from the dusky (14 fin rays) and Eldons galaxias (15 fin rays), both of which also occur in the Taieri River catchment. The roundhead galaxias, flathead galaxias and koaro all have 16 caudal fin rays, and distinguishing characteristics for these species rely on the teeth, colour pattern, and shape of the head. Although roundheads are only known to co-exist with flathead galaxias in a single stream, and roundheads have never been found with koaro, positive identification is probably best left to the experts. Roundhead galaxias grow to a maximum size of about 130 mm, but are rarely found larger than 90 mm long. They occupy a diverse range of low gradient streams, from small weedy drains to braided cobble streams. The roundhead is tolerant of high water temperatures and low flows, surviving droughts by living in remnant pools that remain in ephemeral streams. They spawn in early spring, laying their eggs amongst loose gravel and cobbles in riffles and at the stream edge. Spawning sites are used by many fish, and up to 40 individuals can be found at once in areas smaller than 10 x 10 cm".[43]
Giant Kokopu.jpg Galaxias argenteus Giant kokopu VU IUCN 3 1.svg Vulnerable[45]
2. At Risk
Declining
"The giant kōkopu (G. argenteus) is a large bulky fish that may grow to more than half a metre long and weigh nearly 3 kilograms – though it is very rarely that big. Notable for their silvery-gold markings, these fish prefer slow-moving waters and lakes, and do not move far inland from the coast. In its juvenile form it is caught as whitebait, along with juveniles of four other native species. When it was first discovered that the adults belong to the same species as whitebait, there was widespread disbelief. It is possible that the common name cockabully originated as a European adaptation of ‘kōkopu’ or a variant such as kōkopuru."[10]

"As its name implies, the giant kokopu is the largest member of the Galaxiidae family. Specimens of over 450 mm in length have been reported, although fish in the 200–300 mm range are far more common. The profusion of golden spots and other shapes on the bodies of larger fish are very distinctive, although small specimens may be difficult to distinguish from banded kokopu. The giant kokopu was the first Galaxiidae to be discovered, and it was its colour pattern that led to the generic name Galaxias, referring to the profusion of stars in the galaxy. Many people are surprised to learn that giant kokopu are one of the whitebait species. However, giant kokopu are uncommon in the whitebait catch and usually run late in the season. Little is known of their spawning habits. It is thought that the adults migrate to a common spawning site, but spawning has never been observed or any eggs discovered. Giant kokopu are primarily a coastal species and do not usually penetrate inland very far. They are endemic to New Zealand but are found on the major offshore islands. Like banded kokopu and koaro, they can establish land-locked populations. In streams, they prefer the slow flowing waters that occur in lowland runs and pools. They are also usually associated with some form of instream cover like overhanging vegetation, undercut banks, logs, or debris clusters. It is thought that they lurk quietly in this cover awaiting their prey, which ranges from koura to terrestrial insects such as spiders and cicadas."[46]

WildKōaro 01.JPG Galaxias brevipinnis Climbing galaxias LC IUCN 3 1.svg Least concern[48]
2. At Risk
Declining
 Whitebait species  "Another Galaxias species, kōaro (G. brevipinnis), is found in swift-flowing mountain streams. Many people know it as ‘mountain trout’, but it is not a trout. The kōaro is a handsome fish, dark olive with paler markings, and if you see one out in open water on a fine day, the sunlight glistens along its sides. Some anglers know it as lake whitebait, although the species in lakes do not go to sea like those in rivers. It can grow up to 27 centimetres long."[10]

"The koaro is unlikely to be confused with the other diadromous whitebait species because of its shape. It is more elongate and slender shaped, almost like a tube. The sides and back are covered in a variable pattern of light patches and bands that making the koaro a very attractive fish. Unfortunately, it is not so easy to tell the koaro apart from some of the non-diadromous galaxiids like the Canterbury galaxias and those that live in Southland and Otago. Identification problems are complicated by the fact that koaro can co-habit with the other species in the same rivers and streams. Even the experts have problems separating them, relying on technical measures such as the number of caudal fin rays to ensure correct identification. Koaro have the ability to penetrate well inland in many river systems, and thus have a more widespread distribution than the other whitebait species. In addition to the mainland, they are also found on Chatham and Stewart Island, in Australia, and on the sub-Antarctic Auckland and Campbell Island. Rocky, tumbling streams are the preferred habitat of koaro, and they are almost always found in streams with native bush catchments except for tributaries of upland lakes that may be above the bush-line. Studies in Australia found that koaro spawned in damp areas along the edges of the streams they lived in, relying on subsequent floods to inundate the eggs for hatching. A requirement for dampness could explain their preference for forested streams, and shows why their distribution in New Zealand has probably been curtailed by widespread forest clearance, more so than most of the other Galaxiidae. Although koaro comprise part of the whitebait catch, they also form land-locked populations in lakes. For example, koaro populations occur in the catchments of many of the Rotorua lakes, Taupo, Rotoaira, Manapouri, Tekapo, Pukaki and Wanaka. Koaro populations in lakes were decimated by predation from introduced trout and are now much lower than in pre-European times when they provided a fishery for Maori. In lakes, where smelt have been introduced, koaro have declined even further and are either now confined to tributary streams or have become extinct."[49]

Galaxias cobitinis Lowland longjaw galaxias CR IUCN 3 1.svg Critically endangered[51]
5. Threatened
Nationally Critical
"The little-known group of small, thin galaxiids known as pencil galaxias live most of their lives in the gravels of stream beds. Most distinctive are the longjaw galaxias – two similar and closely related species with a protruding lower jaw. These little fish (up to 7.5 centimetres long) are superbly adapted for picking small aquatic insects from under stones in pools and shallows. Researchers are only now learning about their habits. It is possible that some of these fish may actually live deep in river gravels."[10]

"The lowland longjaw galaxias was first described from specimens caught in the Kauru River, a tributary of the Kakanui River in north Otago. Previously, these longjaw populations were thought to be disjunctive, lowland populations of Galaxias prognathus, the upland longjaw. However, DNA sequencing showed that the Kauru River fish were highly divergent from the other longjaws, and that it is a distinct species. Although its distinctly protruding lower jaw distinguishes this galaxiid from most of the others, it also has only 5 pelvic fin rays, compared to 7 for the other galaxiids, and fewer caudal rays and vertebrae compared to upland longjaws. Based on its location, the new longjaw species was given the common name of lowland longjaw galaxias. This was unfortunate because recent surveys have shown that this fish also occurs in parts of the upper Waitaki catchment and so is not a lowland species. A single specimen from the Hakataramea River in 1989 was positively identified as a lowland longjaw, but no other longjaws have been found there since. How this species came to be present in such widely separated locations is a mystery, although further surveys may show that it is even more widespread. Generally, the lowland longjaw looks similar to its upland cousin; it is a slender elongate fish lacking strong colouration. It is also quite small, rarely exceeding 70 mm in length. Adult fish occur in the margins of riffles and runs, but in daylight are usually hidden under rocks and stones. Spawning occurs in late winter and spring, and juvenile longjaws, which lack the distinctly protruding jaw that adults develop, are readily visible in backwaters and side braids from October to January."[52]

Galaxias depressiceps Flathead galaxias VU IUCN 3 1.svg Vulnerable[54]
3. Threatened
Nationally Vulnerable
"The flathead galaxias is another of the recently discovered non-diadromous Galaxiidae that are only found in Otago, primarily in the Taieri River catchment. It was formally described as a new species in 1996, and its scientific name refers to its distinctly flattened (depressus) head (ceps). Other non-diadromous galaxids with flat heads have been found in the Clutha catchment and in Southland, but recent comparisons by Otago University suggest these are distinct from G. depressiceps with 3 new species awaiting formal recognition. Clearly, sorting out the taxonomy of the Otago/Southland galaxiid complex is going to take more time. At present, this species of flathead galaxias is known mainly from streams in the Taieri catchment, but also the Shag, Waikouaiti and some coastal streams south of the Taieri. The flathead galaxias is difficult to distinguish from some of the other galaxiids that appear to be restricted to the Taieri catchment, although the number of caudal fin rays can be used to distinguish flathead galaxias (16 fin rays) from the dusky (14 fin rays) and Eldons galaxias (15 fin rays). Telling flathead galaxias apart from roundhead galaxias and koaro, also with 16 caudal fin rays, is more difficult, relying on the teeth, colour pattern, and the flattened head. Flathead galaxias often also have a golden stripe down the centre of the back to the dorsal fin and a golden belly. These three species never occupy the same stream, but koaro and flatheads or roundheads and flatheads do co-exist, albeit at few sites. The distribution of the flathead galaxias is fragmented, possibly a consequence of impacts from the introduced brown trout. The preferred habitat for this species is cobble/boulder streams in tussock grasslands, and most populations occur above large waterfalls. Flatheads are found at altitudes of 140-1130 m in Otago, and they can live in steep mountain streams. Flatheads reach a maximum size of 168 mm, but are usually less than 125 mm."[55]
Galaxias divergens Dwarf galaxias EN IUCN 3 1.svg Endangered[57]
2. At Risk
Declining
"The scientific name for this species indicates that it diverges from the other members of the Galaxiidae family: it has only 6 pelvic fin rays compared to the more usual 7 for the other galaxiids. The number of caudal fin rays (15) is also different from most other galaxiids, except for Eldons galaxias. However, dwarf and Eldons galaxias do not co-exist, with Eldons galaxias being confined to Otago. The dwarf galaxias is amber to olive green in colour with dark brown blotches on the sides and back. The belly is silvery. The whole life cycle of the dwarf galaxias occurs in fresh water, and the maximum size of these fish is about 90 mm, although most adults are usually less than 70 mm in length. Aquatic larvae of mayflies and midges are the most commonly eaten foods of the dwarf galaxias. Of the non-diadromous members of the Galaxiidae family, the dwarf galaxias has the widest distribution, although this pattern is extremely fragmented. In the North Island, dwarf galaxias occur in the headwaters of the Waihou River near Putaruru, at a few sites in the Rangitaiki River near Galatea, in Hawkes Bay, and the Wellington region. In the South Island, it occurs in Marlborough and Nelson, and on the west coast as far south as the Hokitika River. Recent studies show there are some genetic differences between the populations, but probably not enough to warrant any separate species"[58]
Galaxias eldoni Eldon's galaxias CR IUCN 3 1.svg Critically endangered[60]
4. Threatened
Nationally Endangered
"This member of the non-diadromous galaxiid group has a very restricted distribution; it is confined mainly to tributaries in the lower to mid Taieri River catchment. This is another new Otago galaxiid species and it was first formally described in 1997. The name honours G.A. Eldon, who assisted Dr R.M. McDowall with his investigations into the galxiidae. Eldons galaxias closely resembles the flathead galaxias, but it has a deeper body and darker colouration, especially in large individuals. Its can also be distinguished from the flathead and other galaxiids by the number of caudal rays (15 in Eldons, 16 in the flathead, and 14 in the dusky galaxias). It shares this characteristic of 15 caudal rays with the dwarf galaxias, but their distributions do not overlap. Although the full extent of their occurrence is not yet known, it appears that the distribution of Eldons galaxias is highly fragmented. This may be caused by competition from the introduced salmonids: brown trout, rainbow trout and brook char. The establishment of land-locked populations of native koaro in Lake Mahinerangi may have also affected their distribution. Eldons galaxias reaches a maximum size of about 150 mm and are commonly found up to 110 mm long. Like most of the non-diadromous galaxiids, Eldons galaxias feeds on aquatic insects, occasional terrestrial items, and on rare occasions, small koura. They can often be seen during the day feeding on items drifting downstream. Eldons galaxias tends to prefer riffle habitats, but can also be found in pools. They occupy a diverse range of streams from high altitude tussock streams to low altitude forested ones. Often they are found upstream of large waterfalls that restrict the distribution of salmonids. Spawning occurs in mid-spring, and the larvae hatch about a month or so later."[61]
Galaxias fasciatus 11.JPG Galaxias fasciatus Banded kokopu LC IUCN 3 1.svg Least concern[63]
1. Not Threatened
 Whitebait species  "Some other species of Galaxias are fairly well-known. The banded kōkopu (Galaxias fasciatus) is another of the whitebait species, with adults commonly growing to around 20 centimetres. It is known as ‘native trout’ or ‘Māori trout’ – but it is no trout... It is greyish-brown with vertical pale bands across its sides – providing camouflage in the dappled light on small bush streams. Banded kōkopu inhabit pools in the smallest streams, some of which are only half a metre wide with scarcely enough room for the bigger fish to turn round. When people live nearby, the fish can be quite tame, taking food from the surface of pools, and even jumping to take it from your hand."[8]

"This member of the Galaxiidae family is one of the five species that occur in the whitebait runs that enter our rivers each spring. Banded kokopu are generally the smallest of the five species when they are whitebait and have an overall golden colour. The juveniles are very good climbers and will often escape from buckets by clinging to and wriggling up the sides. Adult banded kokopu can be distinguished from the other galaxiid species by the presence of the thin, pale, vertical bands along the sides and over the back of the fish. These bands begin to develop quite early, but similar bands also appear on juvenile giant kokopu, and it is easy to confuse young fish of these species. It is probably best to send small specimens to a fish biologist for identification. Banded kokopu commonly grow to over 200 mm, and fish of this size should be no problem to identify correctly. Adult banded kokopu usually live in the pools of very small tributaries where there is virtually a complete overhead canopy of vegetation. This vegetation does not have to be native bush, however, and banded kokopu happily live in urban streams and streams under exotic pine plantations so long as overhead shade is present. They only occur in pools where there is instream cover such as an undercut bank, large rocks or wood debris. They depend on terrestrial insects for a large proportion of their diet and can detect the small ripples made by moths and flies that become stuck on the water surface of the pool. Although the juveniles are good climbers, banded kokopu do not penetrate very far inland and are primarily a coastal species. They are found on Chatham and Stewart Island, but occur only in New Zealand. Banded kokopu are rare along the east coast of the North Island south of East Cape and down the east coast of the South Island, but common elsewhere. This distribution is probably a result of intensive land development and the sensitivity of the juveniles to suspended sediments. Rivers containing glacial flour or eroding sedimentary catchments are not attractive to the whitebait of this species."[64]

Galaxias gollumoides Gollum galaxias CR IUCN 3 1.svg Critically endangered[66]
3. Threatened
Nationally Vulnerable
"This recently described member of the Galaxiidae family was only recognized as a distinct species in the last few years. Because this fish was first found in a swamp and has relatively large eyes, its name refers to its similarity to Gollum, a character in J.R.R. Tolkein's “The Hobbit” and “Lord of the Rings”. Recent studies at Otago University indicated that it occurs on Stewart Island, throughout the Catlins and Southland, and in the Nevis River (which used to drain into the Mataura). The best way to tell this species apart from other galaxiids is by counting the pelvic fin rays; the Gollum galaxias has 6 pelvic fin rays whereas most of the other galaxiids usually have 7. The two galaxiids that also have 6 pelvic fin rays, Eldons and dwarf galaxias, do not co-exist with the Gollum galaxias. No detailed studies of its life history have taken place yet, but its life cycle is probably similar to that of the other non-migratory galaxiids, with spawning taking place in spring, and the whole life cycle occurring in fresh water. The largest Stewart Island fish recorded is 75 mm, but Southland populations contain fish up to 150 mm long."[67]
Galaxias gracilis Dwarf inanga VU IUCN 3 1.svg Vulnerable
2. At Risk
Declining
"The dwarf inanga looks like a small inanga and is closely related to inanga. However, it is found in only 13 lakes near Dargaville in the North Island. As its name implies, it is the smallest member of the Galaxiidae family in New Zealand. Specimens of over 80 mm in length are rare, and mature adults may be only 40 mm. Juveniles school around the lake edges where rushes and macrophytes provide shelter from predators. They feed on zooplankton in open waters at night. Adults occur in deeper water near the middle of the lake and return to the littoral zone at night to feed on the larger invertebrates present there Dwarf inanga populations have declined over the past 30 years, and it is now considered to be a threatened species. The introduction of rainbow trout into some of the lakes it inhabits (especially the Kai Iwi lakes) was initially blamed for this decline, as trout are known to eat inanga. However, removal of trout from one lake did not increase the abundance of dwarf inanga and, up until 2000, it was abundant in Lake Ototoa which was routinely stocked with trout. Gambusia is now thought to be responsible for its scaricty in Lakes Taharoa nd Waikere, and for its extinction in Lake Kai Iwi."[69]
Galaxias macronasus Bignose galaxias CR IUCN 3 1.svg Critically endangered[71]
3. Threatened
Nationally Vulnerable
"The bignose galaxias is yet another non-diadromous galaxiid from the South Island that has only recently been described. It was distinguished as a new species based on DNA sequencing and its morphology. The bignose galaxias is closely related to what are referred to as the “pencil galaxias”, small, slender (pencil-shaped), non-diadromous, mainly sub-alpine galaxiids with small fins and long, slender caudal peduncles (G. divergens, G. paucispondylus, G. prognathus and G. cobitinis). It can be distinguished from these species because it has only 4–6 pelvic fin rays (usually only 5) and only 11–14 caudal rays. It also has a distinctly rounded lateral head profile with the upper margins of the eyes being well below the dorsal profile. Bignose galaxias are found in several locations in the Mackenzie Basin in the upper Waitaki River catchment. Generally it is found in small spring or wetland-fed tributaries. Little is know about its life history, although this is probably similar to the other pencil galaxiids. Sexually mature fish were found in June and July, suggesting spawning takes place in winter."[72]
Galaxias maculatus.jpg Galaxias maculatus Common galaxias LC IUCN 3 1.svg Least concern[74]
2. At Risk
Declining
 Whitebait species  "The most widespread and best known of the galaxiids is īnanga (Galaxias maculatus). Unlike most of its relatives, it is the one Galaxias species that lives in the open waters of pools. It swims in smallish, roving shoals, in pools and runs of lowland rivers and in wetlands".[8]

"Every New Zealander knows what whitebait are, and most have probably eaten a fritter or two in their time. What many people don't realize is that five separate galaxiid species make up the whitebait catch - inanga, banded kokopu, koaro, shortjaw kokopu, and giant kokopu. In most river systems, the inanga makes up the majority of the whitebait catch, and thus this fish is probably encountered more often than other members of the Galaxiidae family. Adult inanga are the smallest of the five whitebait species, rarely exceeding 110 mm in length. Their silvery belly and somewhat forked tail make them easy to distinguish from the other galaxiids except for their close relative the dwarf inanga, a species restricted to some dune lakes near Dargaville. Smelt frequent similar habitat to inanga and can be confused with them. However, smelt have scales and an adipose fin, features that are easy to see on close examination. Inanga inhabit open rivers, streams, lakes, and swamps near the coast and can often be seen shoaling in open water. They are very poor climbers, however, and do not penetrate any distance inland unless the river gradient is very gradual. Inanga are one of the most widespread galaxiids. They occur right around New Zealand and its offshore islands, as well as in South America and Australia. Over the years, much has been said about the decline of the whitebait fishery and possible reasons for it. Fishing pressure was the target of a recent study on the Mokau River, which used dye-stained whitebait to determine the number of fish that escaped past anglers' nets. This showed that whitebaiters caught a relatively small proportion of the run. However, a parallel study showed that only about 20% of the whitebait that escaped survived to reach adulthood. Historically, their abundance has been greatly reduced nationwide by swamp and wetland drainage. Introduced fish (trout, gambusia) are also thought to have reduced inanga. But today, a reduction is spawning habitat is believed to be the major limiting factor. Inanga spawn on river/stream banks among vegetation inundated by spring high tides. The eggs remain above the water level until the next spring tide when they hatch and are washed out to sea. Modification of the tidally affected regions of stream and river banks by cattle browsing and flood control works have no doubt destroyed much spawning habitat. Because they cannot climb small falls, inanga are restricted to the lower reaches of rivers and stream and their access to good habitat can be greatly reduced by poorly designed culverts."[75]

Galaxias paucispondylus Alpine galaxias LC IUCN 3 1.svg Least concern[77]
2. At Risk
Naturally Uncommon
"Alpine galaxias are difficult to distinguish from dwarf galaxias, but Alpine galaxias have 16 caudal and 7 pelvic fin rays compared to 15 and 6, respectively, in dwarf galaxias. There are also white chevron-shaped marks in front of the dorsal fin on alpine galaxias. Although these marks are only visible on live specimens, they can be used to distinguish alpine galaxias from Canterbury galaxias and koaro. In addition, alpine galaxias have a more slender, elongate shape than Canterbury galaxias or koaro. Alpine galaxias have a similar life cycle to longjaw galaxias, and they inhabit many of the same streams at mid to high altitudes draining to the east coast of the South Island. However, alpine galaxias generally live in deeper, swifter water than longjaw galaxias, and their distribution extends further south into Southland. These two species have overlapping diets, but the alpine galaxias reaches a larger maximum size (112 mm) than the longjaw galaxias (87 mm)."[78]
Shortjaw Kokopu.jpg Galaxias postvectis Shortjaw kokopu EN IUCN 3 1.svg Endangered[80]
3. Threatened
Nationally Vulnerable
"As its name implies, the shortjaw kokopu has an undercut jaw, with the lower jaw being shorter than the upper jaw. Koaro also have shortened lower jaws, but they are much more tube shaped than the kokopu. Shortjaw kokopu are also rather drab in colour unlike the sparkly koaro. The main distinguishing feature is a distinctive dark blotch on each side just behind the gills. Otherwise, this fish is essentially brownish with faint bands and blotches. Shortjaw kokopu are endemic to New Zealand and do not occur on Stewart or Chatham Island. Although they penetrate well inland in many catchments, they appear to be restricted to streams with native forest vegetation. Even though it is widespread, the shortjaw kokopu is probably the rarest of the whitebait galaxiids as it is unusual to capture more than a few fish at a given site. It is usually found in streams with large boulders in pools and is difficult to catch using conventional methods. Because this fish has been so rarely encountered, little is known about its life history. In 2009, the first landlocked population was discovered in an Auckland reservoir."[81]
Galaxias prognathus Longjaw galaxias CR IUCN 3 1.svg Critically endangered[83]
3. Threatened
Nationally Vulnerable
"As its name implies, the distinguishing characteristic of this member of the Galaxiidae family is its long, protruding jaw. In fact, its Latin name means exactly that – forward (pro) jaw (gnathos). The long, protruding jaw of the longjaw galaxias is unmistakable, and it is unlikely to be confused with any other species except the lowland longjaw, which has only 5 (compared to 7) pelvic fin rays. The longjaw galaxias is a slender, elongate fish and is one of the smaller galaxiids, rarely exceeding 80 mm in length. The longjaw galaxias is non-diadromous, and the whole life cycle takes place in fresh water. Spawning occurs from March to May and also from October to November. They are nocturnal feeders and live on a variety of aquatic insects, especially mayflies. Studies of their diets showed that they selected soft-bodied prey in preference to harder shelled animals like snails or cased-caddis. Longjaw galaxias generally live at mid to high altitudes in rivers and streams draining to the east coast of the South Island. Like the Canterbury and alpine galaxias, a population also occurs in the headwaters of the Buller River (Maruia River) near Lewis Pass. Although it inhabits swiftly flowing streams, longjaw galaxias are usually found along the quiet river margins."[84]
Galaxias pullus Dusky galaxias CR IUCN 3 1.svg Critically endangered[86]
4. Threatened
Nationally Endangered
"The dusky galaxias is a new addition to the Galaxiidae family that was formally described in 1997. It has a restricted distribution in the Otago region in tributaries of the Taieri and Clutha River catchments. Although it occurs in the same general area as another of the new Otago galaxiids, Eldons galaxias, the two species have never been found together. The dusky galaxias differs from the other galaxiids in having only 14 caudal fin rays compared to 15 for Eldons and dwarf galaxias and 16 for the others. It is generally a brown colour, but with a distinct dark and light colour pattern. It also has darker blotches behind the gill openings that are more characteristic of the diadromous banded and shortjaw kokopu. Adults are commonly up to 110 mm in length, although specimens of 150 mm have been recorded. The dusky galaxias lives in tussock and forest streams at mid to high elevations (400-1000 m), utilizing riffle and pool habitats. Spawning occurs in spring with the fish laying their eggs under overhanging banks in riffles. These fish eat a wide variety of aquatic insects and occasionally terrestrial items that fall in the water."[87]
Canterbury galaxias, Galaxias vulgaris.jpg Galaxias vulgaris Common river galaxias LC IUCN 3 1.svg Least concern[89]
2. At Risk
Declining
"The Canterbury galaxias is a non-diadromous galaxiid that inhabits low to high altitude rivers and streams in the Canterbury Plains. Previously, the Canterbury galaxias and the Otago/Southland galaxiids were thought to be the same species, but DNA analysis revealed that the Canterbury galaxias is different to the others. The Otago/Southland group has now split into eight species, although three of these await formal recognition. Detailed study of the Canterbury galaxias shows that more than one species occurs in this region as well. The new and as yet undescribed species is thought to occur in the northern part of the range – from the Clarence River north. There are three galaxiid species that co-exist with the Canterbury galaxias and that might be confused with this species. Alpine and longjaw galaxias are relatively easy to distinguish, but the koaro is more difficult. Both the alpine and longjaw galaxias are very slender fish, and when alive, the alpine galaxias has distinct white chevron-shaped marks at the front of the dorsal fin. The long, protruding jaw of the longjaw galaxias is unmistakable. In koaro, the lower jaw is obviously shorter than the upper jaw, and this feature can be used to tell it apart from the Canterbury galaxias. Koaro also have a bolder colour pattern with sparkling gold highlights whereas the colouration of the Canterbury galaxias tends to be more subdued. However, colour can vary so much in individual fish that this is not an infallible characteristic to use for identification. Studies show that Canterbury galaxias spawn in September and that mortality of adults can be high after spawning. The male fish excavates a primitive nest, usually under a boulder, and probably mates with several females. Although he guards the nest for a period while attracting females to breed, there is no evidence of any parental care of the eggs or larvae."[90]
Neochanna apoda.jpg Neochanna apoda Brown mudfish EN IUCN 3 1.svg Endangered[92]
2. At Risk
Declining
"Mudfish are probably one of the least known freshwater fish. There are five species in New Zealand, and they have become specialised for life in a distinctive type of habitat – swamps, drains, and forest pools that tend to dry up in summer. They can exist in these habitats because they have the ability to survive out of water during drought. In fact, the first records of these fish often came because specimens were discovered curled up in the mud when wet areas were dug up for drainage or cultivation. Mudfish are an elongate, slender-bodied fish with blunt heads and small eyes. Three of the five species lack pelvic fins, and this is the easiest way to distinguish them from other members of the Galaxiidae family. The brown mudfish occupies central New Zealand, from Taranaki, through Wellington and the Wairarapa, and down the northwest coast of the South Island. As its distribution does not overlap with the other mudfish species, there is little chance of confusing this species with the others. Studies show that mudfish mature during the summer aestivation period and spawn as soon as their habitat is re-inundated in the autumn. This gives the larvae the longest possible period with water present in which to develop and grow. Not all brown mudfish aestivate as some live in permanent water. These populations may spawn at any time of the year. Brown mudfish reach a maximum age of at least seven years and grow to about 150 mm in length."[93]
Neochanna burrowsius Canterbury mudfish CR IUCN 3 1.svg Critically endangered[95]
5. Threatened
Nationally Critical
"As its name implies, this mudfish species is restricted to the Canterbury region. This is the best feature for distinguishing it from the other mudfish, but the presence of pelvic fins on the Canterbury mudfish is also a unique feature of the mainland mudfish species. The Canterbury mudfish can be distinguished from other members of the Galaxiidae family by the presence of fewer rays in the pelvic fins (4 or 5 rays for Canterbury mudfish compared to 7 in the other galaxids). They also have comparatively small eyes. The Canterbury mudfish is found from just north of Christchurch down the east coast to the Waitaki River. It has never been found south of there. It occupies weedy springs, drains, and irrigation races at low to mid altitudes across the plains and it does not usually co-exist with other fish species, probably because they frequent habitats that are subject to drying up in summer. Like the other mudfish species, it can aestivate when its habitat dries up and it remains buried in its hole in the mud until the water returns. Canterbury mudfish lead a precarious existence and are considered to be a rare species. The development and drainage of swampy lands and subsequent lowering of the water table have probably contributed to their decline by reducing and fragmenting their habitat. Recently, a release of Canterbury mudfish occurred in a protected wetland near Willowby south of Ashburton, where it is hoped they will survive and reproduce. The establishment of similar populations in other protected wetlands is also desirable if we are to ensure that this unique New Zealand fish does not disappear."[96]
Neochanna diversus Black mudfish EN IUCN 3 1.svg Endangered[98]
2. At Risk
Declining
"In many respects the black mudfish is similar to the brown mudfish except that it occupies the northern part of the North Island. Its distribution pattern is a good way to tell it apart from the brown and Canterbury mudfish, but the distribution of the newly discovered Northland mudfish overlaps that of the black mudfish. Black mudfish can be distinguished from the Northland mudfish by the number of caudal fin rays; the Northland mudfish has only 13 or fewer rays whereas the other mudfish usually have 14 or more. Black mudfish live primarily in swamps and wetlands and are found from the Mokau River catchment in the south up to Kaitaia in the north. They are quite abundant in the Waikato region, particularly in Whangamarino Swamp, and also occur on the Hauraki Plains. They have a similar life history to brown mudfish, with spawning taking place at the beginning of the wet season and probably continuing through to early spring. In addition to the threat to black mudfish from land drainage and development, these fish are also threatened by the presence of gambusia, an aggressive and prolific introduced fish that has a similar distribution pattern to black mudfish. Observations of their behaviour in tanks showed that large gambusia would readily eat mudfish fry, and that they chased and nipped juvenile mudfish. However, adult mudfish were not harassed, and even attacked the gambusia. Mudfish are able to co-exist with gambusia because they can survive in habitats that periodically dry up, which gambusia cannot do, and because they breed in winter, when gambusia numbers are low."[99]
Neochanna heleios Northland mudfish CR IUCN 3 1.svg Critically endangered[101]
3. Threatened
Nationally Vulnerable
"The Northland mudfish is a newly discovered member of the mudfish genus. As its name implies, it is only found in Northland and only then from a fairly restricted area near Kerikeri. It can be distinguished from the other mudfish species by counting the caudal fin rays; the Northland mudfish has only 13 or fewer rays whereas the other mudfish usually have 14 or more. The body also has a distinct reddish tinge, particularly on the fins. The largest Northland mudfish on record is 134 mm long, and adult specimens regularly exceed 100 mm in length. Little is known about the life cycle of the Northland mudfish, although it is undoubtedly similar to that of the other mudfish species. The distribution pattern of the black mudfish overlaps that of the Northland mudfish, but the two species have never been caught together. The conservation status of the Northland mudfish is uncertain. The largest population occurs in a protected conservation area, but already a separate, smaller population has disappeared in conjunction with deteriorating water quality at the location."[102]
Neochanna rekohua Chatham mudfish LC IUCN 3 1.svg Least concern[104]
2. At Risk
Naturally Uncommon
"As its name implies, this member of the Galaxiidae family is found only on Chatham Island and it is therefore unlikely to be encountered by most New Zealanders. It was discovered in 1994 and at present is only known from remote peat lakes on the southern part of the island. It can be distinguished from most other mudfish by the presence of well developed pelvic fins, and from other galaxiids by the deep caudal peduncle with strong dorsal and ventral flanges. Juvenile Chatham mudfish resemble inanga, but the two species do not co-exist. The Chatham mudfish apparently lives its whole life in fresh water; although little is known about it."[105]
Geotriidae Geotria australis.jpg Geotria australis Pouched lamprey DD IUCN 3 1.svg Data deficient[107]
3. Threatened
Nationally Vulnerable
"Lamprey are parasitic fishes, and New Zealand’s one species (Geotria australis) spends most of its life at sea. It attaches itself to larger marine fish with its sucking mouth, and rasps away its host’s flesh. Lamprey migrate into rivers in late winter and spring. When they first arrive they are bright silver, with a blue back that has two vivid, paler blue stripes. But they soon lose their brilliant colours, becoming dull, drab and brownish. They penetrate long distances up rivers and probably spawn in the headwaters of small bush streams. The larvae hatch, and spend a few years living in sandy or silty sediments of stream margins, before moving to sea for several years. Nothing is known of their breeding habits."[108]

"The lamprey spends most of its life in the sea, where it uses a circular sucker to attach itself to other fish. It feeds by rasping a hole in their flesh and then, like a leech, it sucks out a meal of blood. The adults, which are over 400 mm long, spawn in fresh water, and thus migrate into rivers from the sea to spawn in small headwater streams. The adults do not feed while in fresh water and so are not parasitic on freshwater fish, although North American species in the Great Lakes do feed on salmonids. Lampreys can be distinguished from eels by the presence of the circular sucker instead of a mouth and by the seven gill openings along their sides just behind the head. Male adult lampreys also have large pouches just behind their mouths. When they first come in from the sea, lampreys are bright silvery-blue but soon change to a drab dark grey colour. We believe juvenile lampreys spend up to four years in fresh water before migrating to the sea. At first they are a muddy brown colour and look like small eels. They appear different from eels by having seven gill openings and no eyes. At this stage, they inhabit sandy banks along the sides of streams. As they approach the size for migration to the sea, juvenile lampreys develop eyes and change to a bright silvery-blue, just like the adults. However, they are only about 100 mm long at this stage. Lampreys are found throughout New Zealand, and also in Australia and South America. Despite their wide distribution, they have not been reported from Stewart or Chatham islands. Generally they occur close to the coast at low altitudes. On returning to freshwater to breed, adults can use their circular sucker to latch onto and surmount obstacles such as rapids and small falls. Little is known about their breeding habits. Lampreys were an important food resource for Maori, and elaborate weirs were constructed to catch them. This traditional fishery still occurs on a small scale in the Wanganui River near Pipiriki."[109]

Mugilidae Aldrichetta forsteri Yellow-eye mullet LC IUCN 3 1.svg Least concern[111]
1. Not Threatened
"There are two members of the Mugilidae (or mullet) family in New Zealand, the yelloweyed mullet and the grey mullet. The mullet family has a worldwide distribution in rivers and seas of all regions except the Arctic and Antarctic Oceans, with about 70 species in total. The two species found in New Zealand are not really freshwater fish, but both are common in river estuaries and they can penetrate upstream for several kilometres in large rivers. All mullets have two dorsal fins, and the first one is tall with four obvious spines. They also have large, easily dislodged scales. New Zealand mullets belong in two separate genera based on the presence of an adipose eyelid. This is a thick fleshy eyelid that forms an oval, vertical slit over the pupil on the grey mullet. For amateurs, however, the bright yellow eye of the appropriately named yelloweyed mullet is probably the easiest way to distinguish the two species. Yelloweyed mullet occur all around New Zealand and they are also found in western and eastern Australia. They are never found far from the coast. Yelloweyed mullet are very familiar to any youngster who has spent time fishing off wharves or in harbours, competing with the spotty as the most easily caught fish. Fish 150–200 mm long are commonly caught, although fish of up to 500 mm have been reported. Yelloweyed mullet may spend considerable time in fresh water, for example they are found at all times of the year in Lake Ellesmere south of Christchurch, but their spawning takes place in the sea."[112]
Mugil cephalus.jpg Mugil cephalus Flathead grey mullet LC IUCN 3 1.svg Least concern[114]
1. Not Threatened
"The grey mullet is the second member of the Mugilidae (or mullet) family found in New Zealand. In common with the yelloweyed mullet , the grey mullet has two dorsal fins, the first being tall and with four obvious spines. They also have large, easily dislodged scales. Technically, the way to tell the two species apart relies on the presence of the thick fleshy adipose eyelid found on the grey mullet. However, grey mullets also lack the bright yellow eye found on the appropriately named yelloweyed mullet. Grey mullet have a worldwide distribution and New Zealand is at the southern limit of their range. Hence, they are mainly found in the North Island, and only in the Cook Strait area during the summer months. Although primarily a marine species, grey mullet will penetrate considerable distances upstream. In the Waikato River they are found as far inland as Karapiro Dam and travel up the neighbouring Waipa River to Te Kuiti. However like the yelloweyed mullet, they must return to the sea to spawn. Grey mullet feed on detritus and plant material that they suck from the substrate. They are also known to feed by grazing the surfaces of aquatic plants. Grey mullet are large fish, commonly reaching 500 mm in length. They are regarded as a valuable food fish, and are particularly nice smoked because of the oily flesh. In many parts of the world they are farmed commercially, but in New Zealand most of the commercial catch comes from fishers operating on Kaipara and Manukau Harbour and in the lower reaches of the Waikato River. Tagging studies of grey mullet in this area showed that there was considerable movement of fish between the river and harbours, and that commercial and recreation fishers extracted a significant proportion of the grey mullet population."[115]
Pingui-
pedidae
Torrentfish.png Cheimarrichthys fosteri Torrentfish VU IUCN 3 1.svg Vulnerable[117]
2. At Risk
Declining
"The little torrentfish (Cheimarrichthys fosteri) spends most of its life in flowing torrents. Its superbly adapted fins act as depressors, keeping it on the stream bed under swiftly flowing water. It may be a close relative of the marine blue cod. Like many New Zealand freshwater fish, torrentfish spend a part of their lives at sea, though it is uncertain how this happens. Nothing is known of their reproduction. What is known is that in spring, juveniles (around 2 centimetres long) can be found swimming into estuaries from the sea. Scientists suspect that they migrate to sea as newly hatched larvae."[108]

"This little fish is the only freshwater member of the Pinguipedidae family in New Zealand. Closely related to the more familiar blue cod, the scientific name of this fish means literally torrent (cheimarros) fish (ichthyos). And it’s an apt name for this species because that is exactly where this fish lives - right in the swift white rapids of stony rivers and streams. The flattened head and large pectoral fins help this fish to anchor on the riverbed, while the raised eyes and ventral mouth are probably adaptations for feeding in this habitat. These later two features, along with the distinct dark bands along the sides, easily distinguish the torrentfish from other freshwater species. Despite its skill at living in swift water, the torrentfish is not a good climber and only penetrates inland in river systems where the gradient is relatively low. It is less common in Otago and Southland than in other parts of New Zealand, and torrentfish have never been reported from Fiordland, Stewart, or Chatham Islands. It is not found in any other country except New Zealand. Like many of New Zealand’s freshwater fish, the torrentfish undertakes migrations between the sea and fresh water as part of its life cycle. Looking just like tiny replicas of the adults, juvenile torrentfish enter fresh water in spring and autumn, and after a few weeks in the estuaries, begin moving upstream to the adult habitat. The adults continue to move slowly upstream, with the largest and most inland fish being the females and those in the lower reaches predominately males. How and where they get together for spawning is unknown - we suspect the females move downstream to the males, but no spawning sites or spawning behaviour has ever been observed. Despite the mystery surrounding aspects of its life cycle, torrentfish are one of the most common fish in open-bedded rivers in New Zealand."[118]

Pleuro-
nectidae
Rhombosolea retiaria (Black Flounder).gif Rhombosolea retiaria Black flounder DD IUCN 3 1.svg Data deficient[120]
1. Not Threatened
"The black flounder (Rhombosolea retiaria) spends much of its life in either rivers or lowland lakes. It is notable for the bright brick-red spots on its back. It migrates to sea to spawn, probably during winter, though little is known about this. Small juveniles, around the size of a thumbnail, can be found making their way into the rivers over spring."[108]

"The black flounder is the only member of the flatfish family, or Pleuronectidae, that is a truly freshwater species. Other members of the family, such as the yellowbelly flounder, occasionally wander into the lower reaches of rivers, but do not usually stay there. As their name implies, the flatfishes are indeed flat, and have adopted a habit of laying on their sides right down on the substrate. Both eyes are on their dorsal or upper side to improve their field of view. Because of their unusual shape, flounders are unlikely to be confused with other fish species except other flounders. The black flounder is easily distinguished from other flounders by the colouration; the top of the fish is usually dark-coloured with numerous, obvious brick-red spots. Flounders can grow to about 450 mm in length, although 200–300 mm fish are more common. The black flounder is found throughout New Zealand but is unique to this country. They have not been reported from Chatham or Stewart Island. They are primarily a coastal species, although they can penetrate well inland if the river gradient is not too steep; specimens have been recorded more than 100 km inland in some river systems. Little is known about the life cycle of the black flounder. The larvae are undoubtedly marine, but where and when spawning takes place is a mystery. Black flounder are a carnivorous species and probably eat a variety of bottom dwelling insects and molluscs. They are also known to feed on whitebait during the spring migration."[121]

Retro-
pinnidae
(smelts)
Prototroctes oxyrhynchus.jpg Prototroctes oxyrhynchus New Zealand grayling EX IUCN 3 1.svg Extinct[123]
† Extinct
"Although once common in New Zealand, grayling (Prototroctes oxyrhynchus) began to decline soon after European settlement. They were last noted in the early 1920s. It is not clear what caused their disappearance, but it could be linked to land use or the introduction of trout."[3]

"Closely related to the smelt was a fish, now extinct, known as upokororo (Prototroctes oxyrhynchus). The early settlers called it grayling, but it is not related to the true grayling of the northern hemisphere. It is New Zealand’s only extinct freshwater fish species, having disappeared by the 1920s for reasons that have not been identified. It was among the larger native fish – probably growing up to 45 centimetres – and looked like an overgrown smelt."[11]

"Most New Zealanders are well aware that some of our native bird species, such as the huia and moa, are now extinct. Few also know that the same is true of one of our native fish species, the grayling. This fish, which is closely related to the smelts, was the only member of the Prototroctidae family in New Zealand. Today, there are probably only a couple of dozen specimens in existence, carefully preserved in museum collections. Fortunately, a closely related species still lives in Australia and studies on this grayling have given us some insight into our own species. The grayling commonly grew to 200–400 mm in length and was a shoaling species like the common smelt. It was widespread and common in the early 1800s, and appeared to reside in lowland rivers and streams during summer, autumn, and winter. It was New Zealand's only herbivorous fish, grazing on the periphyton present on rocks and boulders. Its life cycle was probably similar to that of the whitebait species and common smelt, with the fish growing and spawning in fresh water, and the newly hatched larvae being washed out to sea to live for several months before migrating back to rivers. Grayling numbers began to decline soon after Europeans arrived in New Zealand, and as early as the 1870s biologists were expressing concern about their decline. In 1930, they were officially described as being on the verge of extinction by the Marine Department. Why the grayling became extinct is a mystery, but the introduction of trout and widespread forest clearance that rapidly followed European settlement are thought to have contributed to their demise."[124]

Retropinna retropinna (New Zealand smelt).gif Retropinna retropinna New Zealand smelt LC IUCN 3 1.svg Least concern[126]
1. Not Threatened
"There are two New Zealand species in the Retropinnidae family, the common smelt and Stokells smelt. This family of fishes, known as the southern smelts, is also found in Australia, but the two species we have here are unique to this country. Smelt can be distinguished from other species by the presence of the adipose fin, a small fleshy lobe on their back between the dorsal fin and the tail. They also have scales, a distinctly forked tail, and a cucumber-like smell. The two species that live in New Zealand are very difficult to tell apart, and positive identification depends primarily on the size and number of the scales. Smelt are a shoaling species, which means they swim in schools near the water surface rather than resting or hiding on the substrate. Thus, they are often seen out in the open in streams and lakes as they feed on drifting food organisms. The common smelt is widespread throughout New Zealand, including Stewart and Chatham Island. They live in flowing and still water, and there are both diadromous (sea-going) and non-diadromous (land-locked) populations in New Zealand, although humans have established many of the latter. Although they are not a climbing species, smelt are good swimmers and will penetrate well inland in river systems that are not too steep (e.g. the Wanganui or Manawatu Rivers). They are particularly abundant in the Waikato River catchment. Of the freshwater fish that live in New Zealand, smelt are one of the most sensitive to pollutants like ammonia and stressors such as high water temperature. In some cases, they are as intolerant as the salmonids, which are often used as a benchmark species overseas for establishing water quality guidelines to ensure fish are protected from human activities. Smelt are therefore an appropriate native species for establishing guidelines for New Zealand waterways and usually their presence indicates that the water quality is suitable for most other fish. In most North Island lakes, smelt are the main prey species for trout. In rivers, juveniles are often captured by whitebaiters as they migrate upstream and mix with the whitebait (galaxiids)."[127]
Stokellia anisodon Stokell's smelt LC IUCN 3 1.svg Least concern[129]
2. At Risk
Naturally Uncommon
"Stokells smelt is the second of the two smelt species found in New Zealand. Although it superficially resembles the common smelt, it is sufficiently different, at least to biologists, to warrant a new generic name, Stokellia. This name honours G. Stokell, a biologist who collected and studied New Zealand’s freshwater fish for over 40 years, and who did much to identify and classify the species. Stokells smelt has smaller scales than the common smelt, a feature that only an expert would recognise. The teeth, which are not a very obvious feature, are used to tell the two species apart. The small, fleshy, adipose fin can be used to distinguish smelt from galaxiids, however, smelt can be distinguished from the salmonids (which have an adipose fin) by the absence of a lateral line. Found only on the east coast of the South Island between the Waiau and Waitaki Rivers, Stokells smelt is a strictly coastal species and is never found very far inland. In fact, this species probably spends most of its life in the marine environment. They enter fresh water to spawn in late spring and summer, and can be extremely abundant at times, providing a feast for the trout, kahawai, and sea birds that prey on the annual migrations. Stokells smelt grows to about 95 mm in length, but mature adults are typically 70–90 mm long."[130]
Triptery-
giidae
Forsterygion nigripenne Estuarine triplefin LC IUCN 3 1.svg Least concern[132]
1. Not Threatened
"The estuarine triplefin is primarily a marine species, but it also occurs in river estuaries throughout New Zealand. It can be easily distinguished from other freshwater species by the presence of the three dorsal fins, a feature it shares with other members of the Tripterygiidae family. Although the other members of the family are strictly marine dwelling, there are a number of poorly differentiated species and the taxonomy of this family is in confusion. Until fairly recently, this species was known by the scientific name of Tripterigion nigripenne, but it has had several other names over the years, including T. robustum and T. varium. The current consensus is that it belongs in the Grahamina genus, with the specific name still in doubt. The estuarine triplefin is found throughout New Zealand and is probably much more common that the distribution map indicates. This is because it probably does not actually live in flowing fresh waters, only going upstream as far as the tidal influence extends. Tidal habitats are difficult to sample with conventional methods. It is also an abundant species on rocky shores along the coast. Triplefins reach maturity at about 55 mm in length, and commonly reach sizes of 80–100 mm. Breeding in triplefins appears to occur over an extended period from winter through summer. Like members of the Gobiomorphus genus (bullies), male triplefins establish and defend territories during the breeding season, and try to attract and breed with as many females as possible. After the eggs are laid in a primitive nest, which is usually the underside of a large rock, the male remains to guard them until hatching."[133]

Eels[edit]

"Freshwater eels are fish, and belong to the family Anguillidae. Slow growing and long lived, they begin life in the sea, and then spend many years in fresh water as adults. Finally they return to sea to spawn, after which they die. Many people are scared of eels, because they are snakelike and slimy, and can slither over land. There are very few reports of eels attacking, but if they do, their teeth can grip. In one incident a longfin eel bit the wetsuit of a diver, who had to use a knife to release its hold. Unlike nearly all other freshwater fish, eels have a long cylindrical shape, and continuous dorsal (back), caudal (tail) and anal fins. They have pectoral (side) fins but no pelvic fins. Covered in a layer of mucus, eels are extremely slippery. Although they seem to lack scales, under the microscope you can see a mosaic of tiny scales in the leathery, slimy skin. Eels can travel over land, slithering through wet grass to get to a pond or lake. As long as their skin stays moist they can absorb oxygen through it, surviving long periods out of water. Freshwater eels are found worldwide. Of 15 recognised species, most occur in the waterways that flow into western Pacific and Indian oceans. There are none that spawn in the eastern Pacific or the South Atlantic."[134]

New Zealand eels[edit]

"Eels are New Zealand’s top native freshwater predators – no other species prey on them when they are adult. Māori identified many different varieties, mainly by colour. But when European settlers first arrived in New Zealand there was debate about the number of species. There are three species, all from the Anguillidae family of fish:

  • longfin eel (Anguilla dieffenbachii), found further inland
  • shortfin eel (A. australis), found on the coast
  • spotted eel (A. reinhardtii), which may have recently arrived from Australia and is found only in northern rivers.

The longfin and shortfin eels are found all around New Zealand. They have very varied coloration, so this is not the best way to identify them. The most reliable distinguishing feature is the length of the back fin – hence their names."[14]

Longfin eel[edit]
Shortfin eel[edit]
Spotted eel[edit]

"The spotted eel also occurs in eastern Australia, New Caledonia and Lord Howe Island. It was first confirmed in New Zealand waters in 1997, and is currently only found in rivers from Taranaki to Northland. It has a distinctive colour pattern – mottled or blotched on the back, with yellowish pectoral fins. This eel grows to 1.5 metres and 14 kilograms. The maximum reported age is 41 years."[14]

"Diet and feeding: Eels were once considered a threat because they ate introduced trout. But they are now economically important in New Zealand, and there has been considerable research into their diet. Big longfin eels may eat species such as juvenile trout – larger prey than that of the shortfin or spotted eel. One 9-kilogram eel was reported to have eaten an entire shoveller duck. Small (less than 50-centimetre) longfin and shortfin eels generally feed on snails, insects, worms, grubs, crayfish and small fish. Eels feed mainly at night, using their powerful sense of smell to track prey. Once an eel is close, taste buds on its head and sensors along its sides help locate the victim."[135]

"The largest recorded longfin eel is a 24-kilo specimen taken from Lake Waihola, south of Dunedin, in 1974. At Lake Ellesmere (Te Waihora) in Canterbury, shortfin eels longer than 50 centimetres increasingly become fish-eaters, preying on cockabullies and smelt. Feeding drops off during winter in both species, especially in southern New Zealand. Growth rates are slow. Longfin eels grow at around 2.5 centimetres a year at a length of 30 centimetres, and they slow down to only 1.5 centimetres a year at a length of 1 metre. Shortfin eels grow a little faster. These slow rates are a result of temperature, food supply and competition. Faster growth rates have been achieved in trials to fatten eels in farm ponds."[135]

Life cycle[edit]
Hydroelectric dams can present obstacles to migrating fishes

"Freshwater eels have a remarkable life cycle, which begins and ends in the ocean. Spawning has never been observed. Adult eels probably spawn at some depth in warm seas. New Zealand’s shortfin eels produce 1.5–3 million eggs, and the longfins 1–20 million eggs. Males fertilise the eggs. After spawning, the adults die.cFertilised eggs hatch at the surface and become leaf-shaped larvae, floating on ocean currents towards the coast. They have teeth, but it is not clear for what purpose – they may store calcium for bone development. Their skin may absorb nutrients, as researchers have not found food in the larvae.cOnce the larvae reach land, an extraordinary transformation takes place: they become slender, transparent eels, known as glass eels. They arrive at New Zealand’s coast from July to December, with numbers peaking in spring (August–October) – the time of whitebait migration. Glass eels migrate into river mouths or estuaries in astounding numbers.cHydroelectric dams are an obstacle to elvers (young eels) swimming upriver. Some dams have special passes, allowing them to get round the massive concrete walls. But they don’t always need this help. Elvers can climb the 43-metre Arapuni Dam on the Waikato River, and the 75-metre Patea River dam in Taranaki. Glass eels soon turn grey-brown, and in this form they are known as elvers. They migrate upriver, often in swarms and usually at night. Young elvers can climb waterfalls, but lose this skill as they grow. Elvers become adults, with bigger heads and fatter bodies. After many years in fresh water, eels migrate back down the waterways to the sea. It is thought that males fertilise the eggs once the females spawn out at sea. When they reach breeding size, eels change from ‘yellow-bellies’ to ‘silver-bellies’. The yellow-grey underside becomes grey-white, the head shape changes and the head, back and pectoral fins darken."[136]

"Shortfin males migrate in February–March, and longfin males in April. The females soon follow, and both males and females die after spawning. Studies show the species also migrate at different ages: Shortfin males at an average of 14 years (38–58 centimetres), females at 22 years (50–100 centimetres). Longfin males an average of 23 years (48–74 centimetres), females at 34 years (75–180 centimetres). It is not known how long the journey takes. One female longfin eel that was tagged took 161 days to swim from Canterbury’s Lake Ellesmere (Te Waihora) to a point 160 kilometres north-east of New Caledonia. Barriers across waterways have hampered their route. One estimate suggests that hydroelectric dams have blocked the longfin eel’s access to the sea in 35% of its habitat."[136]

"For centuries, larval eels were thought to be a separate species: they occur in the ocean and look different from adult, freshwater eels. Then in 1896 the Italian zoologist Giovanni Grassi reported that Leptocephalus brevirostris, known as a saltwater fish, was in fact the larva of the European freshwater eel. But just where at sea they bred was a mystery. Searching for breeding grounds: In a 1923 paper, Danish biologist Johannes Schmidt stated that American and European eels spawned in the Sargasso Sea, in the Atlantic. In 1926, after sailing his research vessel Dana II to Australia and New Zealand, he concluded that New Zealand eels probably bred somewhere east of New Caledonia. But the exact locations are still not fully known."[136]

"Longfin eels: At migration, longfin eels are more ready to reproduce than shortfin eels. Scientists thought this meant their spawning grounds were closer to shore. However, a study showed that the longfin eel had the longest larval stage of any Pacific freshwater eel reported. This suggests that the larvae actually hatch further away from New Zealand, possibly near Tonga. They were also the biggest specimens when they reached coastal waters – so they may have been at sea longer, and travelled further."[136]

Export and fishery management[edit]

"Freshwater eels have become an important export, often live or as processed products. They go mainly to South-East Asia, Europe and Canada. Annual sales ranged from $800,000 to $3.5 million between 1990 and 2004. Live eels and products such as smoked fillets, whole smoked eels or skinned segments are available from local processors and restaurants. Worldwide, eel production is declining because of overfishing of glass eels (juveniles) and adults, and damage to the environment. Many countries farm eels, usually sourced from wild glass eels. International demand for wild glass eels for use in eel farms is strong. The market is subject to fluctuations, and high prices can be paid. Through the Quota Management System the New Zealand government controls and monitors commercial fishing, limiting the total catch to ensure sustainability."[17]

"In 2000, the South Island’s shortfin and longfin eels came under the quota system. Both species were treated as a single stock. In 2004 the North Island eel fisheries were included, but the two species were managed separately. Treating South Island shortfin and longfin eel fisheries as a single stock is questionable. Longfin eels breed later in their lives than shortfin eels, which makes them more vulnerable to overfishing."[17]

Links[edit]

Human impacts[edit]

Overview[edit]

"In, ecology, and status of New Zealand's freshwater Fisheries resources are reviewed. Rivers are the main freshwater features in these Pacific temperate-zone islands. Geological events, the islands' remoteness, and the recent nature of human colonization (first Maori and then European) have shaped the freshwater ichthyofauna. Diadromy is a dominant ecological feature for many indigenous species. Many species have also been introduced to create Fisheries. Traditional Maori Fisheries are focussed on indigenous eels and whitebait while recreational Fisheries target introduced salmonids. Management of New Zealand freshwater Fish is dispersed among several departments. New Zealand habitats are pristine by global standards due largely to the recent settlement of European colonists. Many rivers have been impounded for electricity generation; this constitutes the main environmental issue for freshwater Fish. Intensification of agriculture also poses a growing eutrophication threat. The ecologies of indigenous species are becoming better known but much knowledge is anecdotal. Efforts to conserve indigenous freshwater species are increasing. Impoundment, irrigation, deforestation, and introduced salmonids, are the main threats to the native fauna."[137]

New Zealand whitebait[edit]

"74 per cent of the country's native freshwater fish are now listed as threatened. Dr Joy said that was up on 68 per cent in 2009 and 30 per cent at the first review in 1992. New Zealand's figures were worse than any other country that kept such measurements. The global average was 35 to 37 per cent threatened. Dr Joy said native freshwater fish were like miner's canaries measuring the health of rivers."[138]

"Many New Zealanders consider whitebait a delicacy, with its sweet, tender flavour. Often lightly cooked in fritters, the tiny fish are eaten head and all. They fetch a high price in the netting season... In their juvenile form, īnanga are well known as the chief species in the whitebait fishery, which is made up of juvenile fish of five different Galaxias species".[8]

About 90% of the whitebait is made up of juvenile īnanga <ref?>

Links[edit]
Videos
misc
  • Tempero, G. W., Ling, N., Hicks, B. J., & Osborne, M. W. (2006). Age composition, growth, and reproduction of koi carp (Cyprinus carpio) in the lower Waikato region, New Zealand. New Zealand Journal of Marine and Freshwater Research, 40(4), 571-583.

Biogeography[edit]

"New Zealand has been isolated in the southwestern Pacific Ocean since it separated from Gondwana during the Cretaceous period, some 80 million years ago. This prolonged geological isolation, combined with the islands’ very vigorous geological history, impacted by oceanic submergence, tectonic activity, mountain building extreme volcanism, and great climatic variability, create a dynamic scenario within which the New Zealand biota, including its freshwater fishes, have evolved over millions of years. These impacts have contributed to a highly dynamic biological history with undoubted though little understood extinction and vigorous colonisation of the islands’ fresh water. One of the key elements for understanding the origins and derivations of this fish fauna is that in all groups some or all of the species are diadromous, customarily spending a significant phase of their lives at sea. This has no doubt contributed in an important way the fauna’s origins as well, there has been frequent loss of diadromous behaviours leading, to species that have abandoned their sea-migratory behaviours and which now complete their entire lives in fresh water. The distribution patterns reflect these changing habits, with diadromous species being broadly distributed but tending to be lowland in range, whereas the derived, non-diadromous species have narrower ranges, but are often found further inland and at high elevations." [15]

According to McDowall, New Zealand has a biota that" has broad relationships, primarily around the cool Southern Hemisphere, as well as with New Caledonia to the north. There are hints of ancient Gondwanan taxa, although the long-argued predominance of taxa derived by vicariant processes, driven by plate tectonics and the fragmentation of Gondwana, is no longer accepted as a principal explanation of the biota’s origins and relationships... Most of the terrestrial New Zealand flora and fauna has clearly arrived in New Zealand much more recently than the postulated separation of New Zealand from Gondwana, dated at c. 80 Ma. There is a view that New Zealand may have disappeared completely beneath the sea in the early Cenozoic, and acceptance of this would mean derivation of the entire biota by transoceanic dispersal. However, there are elements in the biota that seem to have broad distributions that date back to Gondwanan times, and also some that are thought unlikely to have been able to disperse to New Zealand across ocean gaps, especially freshwater organisms. Very strong connections to the biota of Australia, rather than to South America, are inconsistent with the timing of New Zealand’s ancient and early separation from Gondwana and seem likely to have resulted from dispersal."[139]

Dispersal biogeography[edit]

"The broad distribution of freshwater fishes of the lamprey families Geotriidae and Mordaciidae and the salmoniform Galaxiidae and Retropinnidae in the southern cool temperate zone, has caused prolonged perplexity and debate. Arguments in favour of both a dispersal biogeography and a Gondwana-based vicariance biogeography have been presented. These are not necessarily alternatives. Main conclusions – Evidence from:

  •  Distribution patterns in relation to life-history strategies;
  •  Genetics and morphology;
  •  Different elements in the New Zealand fauna and their relationships;
  •  Recent dispersal events;
  •  Geological history of the Falkland Islands and the relationships of its freshwater fishes; and
  •  Parasitology;

all support, or are consistent with, a dispersal biogeography of this southern cool temperate fauna. The groups involved are sufficiently ancient to have formerly inhabited Gondwana, but no compelling evidence indicates that present distributions reflect a former broad Gondwana-based range. A role for dispersal in these fishes is consistent with increasingly common claims for dispersal in other taxa. This does not mean that there was no ancient influence from Gondwanan vicariance."[140]

See also[edit]

Other references[edit]

34 (1): 185–194.


  • Jellyman, P. G., & Harding, J. S. (2012). The role of dams in altering freshwater fish communities in New Zealand. New Zealand Journal of Marine and Freshwater Research, 46(4), 475-489.
  • Joy, M. K., & Death, R. G. (2013). "Freshwater biodiversity" Ecosystem Services In New Zealand, Manaaki Whenua Press, Lincoln, New Zealand.
  • Weeks, E., Kingsford, R. T., Taylor, A., & Joy, M. (2014). Protecting the future of New Zealand’s freshwater ecosystems.
  • McDowall, Bob . Freshwater fish Te Ara - the Encyclopedia of New Zealand, updated 9-Jul-13.

Taxonomically undetermined species (14)[edit]

"Fourteen native entities are listed as taxonomically indeterminate and are awaiting formal description.

Non-resident native species (3)[edit]

Introduced and naturalised species (20)[edit]

Defined by the Department of Conservation as "taxa that have become naturalised in the wild after being deliberately or accidentally introduced into New Zealand by human agency".

20 species

Introduced fish[edit]

"In the late 1800s and early 1900s, British settlers introduced fish of the Salmonidae family – trout and salmon – to New Zealand. Some of these species now form important recreational fisheries. Less well known, and usually much less widespread, are 15 other introduced species. These are known as coarse fish – many have coarser scales than trout and salmon."[147]

Trout and salmon[edit]

"From the late 1800s, British settlers introduced fish of the Salmonidae family – trout and salmon – to New Zealand. Many species were released, yet only three established themselves well enough to form important fisheries: brown trout, rainbow trout and Chinook salmon. European settlers brought trout and salmon to New Zealand’s lakes and rivers so they could fish them for sport. The most common species today are brown trout, rainbow trout and Chinook salmon."[148]

=Sea-going trout[edit]

"In the late 1800s and early 1900s it was thought that sea trout were a different species from riverine trout. But it has long been known that some brown trout live in estuaries and also go out to sea. Today it is accepted that riverine and sea trout are merely variants of brown trout. Brown trout’s colours can change depending upon the waterway they live in. Sea-run trout can be a bright silvery colour, brown trout from rivers tend to be golden brown, and those from lakes are a duller silver. All have black spots, and riverine browns also have red spots."[149]

Taupō trout[edit]

"Soon after they were brought to New Zealand, rainbow trout grew very large in Lake Taupō, but then declined in size. The average weight of trout in one angler’s bag was 10½ pounds (4.8 kilograms) in 1911, but by 1918 it had dwindled to 4 pounds (1.8 kilograms). The early bonanza was probably due to the trout feeding on the then plentiful native fish."[150]

Chinook salmon life cycle[edit]

"Life cycle: Females and males pair up and the female digs a depression in a gravel stream bed and lays eggs. The male deposits his milt to fertilise them. Eggs hatch into alevins (fry with yolk sacs attached) in spring. After the yolk sac is used up, the fry emerge from river gravels in streams that they use for spawning. They spend about three months swimming downstream, entering the ocean in summer. In the sea the young salmon feed on small fish and crustaceans, and grow rapidly into adults. At maturity (3–4 years) they swim upstream in ‘runs’ or large numbers to spawn in the upper reaches of rivers. After spawning all adults die. The size of salmon runs changes from year to year. The best river was the Waitaki, but much of its glory was lost after the government built a dam at Kurow in 1935 – greatly reducing the size of the salmon run from perhaps 100,000 fish to 10,000. A fish ladder was built up the side of the dam but it was poorly designed and never worked. In the 2000s, upriver runs consist of a few thousand fish in each of the main rivers. Anglers probably catch 35–40% of them. In any given year the total run has varied between 10,000 and 75,000 fish – most years being at the lower end. Hatcheries: attempts to raise numbers' The variability of salmon runs led to efforts to enhance the size by hatching and releasing young salmon. In Canterbury, wild salmon were trapped and stripped of ova in spawning streams. During the 1980s, fish reared in hatcheries on the Rakaia River increased the size of runs. But the cost per fish reared was too high, and runs were still variable."[151]

"There were also plans for "ocean ranching" – commercialising the fishery – in the 1970s and 1980s. The theory was that hundreds of thousands of salmon would be hatched from ova and released. They would go to sea and feed at no cost and come back as adults to be harvested. The plans went ahead and the salmon were released, but they did not come back. In the 2000s commercial salmon farms operated at South Island freshwater sites such as Waikoropupū Springs near Tākaka, and the Tekapo canal in the Mackenzie country. But most farmed salmon were reared in sea cages in the Marlborough Sounds and Stewart Island."[151]

"The average survival rate for smolt [young salmon migrating to the sea] is less than one per cent, and anglers catch about a third of the returning fish, so for every salmon caught you have to release 300 smolt. To significantly improve the number of returning salmon you’d have to annually release 300,000 to 500,000 smolt, and they cost a dollar each to rear. This means each fish costs between $300 and $500."[152]

"Research suggests that conditions out at sea may determine the number of salmon that return. Conditions in the rivers are also a factor. In spring and summer, juvenile salmon make their way downriver to the sea. Floods can kill juveniles or wash them out to sea. Stable flows give them a chance to stay longer in the river and so reach a greater size by the time they go to sea. Those that get to sea at three months of age make up 75% of returning adults."[151]

Other salmonids[edit]

"In the late 1800s and early 1900s attempts were made to introduce other salmonid species such as whitefish, Atlantic salmon, brook char and mackinaw – but with little success."[153]

"Whitefish (Coregonus clupeaformis): Much effort went into acclimatising this species, native to high-latitude lakes in the northern hemisphere. From 1876 to 1907 nearly 10 million ova were brought in. Some whitefish were hatched and released into lakes, but the species never became established."[153]

Introduced and naturalised: Game fish
Family Image Scientific name Common name Fish-
base
IUCN status Comments
Salmonidae Lake Washington Ship Canal Fish Ladder pamphlet - male freshwater phase Steelhead.jpg Oncorhynchus mykiss Rainbow trout
Not assessed
"Rainbow trout were imported in the 1880s. They did not spread and breed as well as brown trout. Today, anglers often catch rainbow trout weighing 2–3 kilograms. They live in lakes such as Lake Rotorua and Lake Taupō, and rivers flowing in and out of these lakes. They do not migrate to sea. They are easier to catch than brown trout. In winter, fishermen catch them in the Tongariro River, upstream from Lake Taupō. They usually live for four to five years."[148]

"Rainbow trout (Oncorhynchus mykiss) were first introduced to New Zealand in the early 1880s. They are descended mainly from Californian steelheads – rainbow trout that migrate to sea and spend most of their lives there. However, New Zealand rainbow trout do not migrate to sea. Rainbow trout are less widespread than brown trout. There has been virtually no natural dispersal. Ova imported in 1883 by the Auckland Acclimatisation Society survived, and fry were released into local waterways. In 1892 the species was liberated in Lake Rotorua, and in 1897 in Lake Taupō. Rainbow trout can tolerate higher water temperatures than brown trout: they are found in warmer waters such as the Kai Iwi lakes in Northland. They also occur in a few rivers. Stocks were also released into many rivers, but they mostly disappeared. Nearly all the rivers where they did establish themselves flow into large lakes – in the central North Island, and the southern South Island. It is not understood why rainbows have failed to become established in many waterways. Adding to the mystery is their presence in a few rivers that do not drain into lakes, such as the Pelorus and Rai in the South Island, and the Mōhaka in the North Island. These have very stable riverbeds, which may be a factor."[150]

"Rainbow trout eat more and grow faster than brown trout. In rivers they feed in fast water, using energy to stay in the same place while feeding on drifting invertebrates. In lakes, rainbows tend to live in deeper water than brown trout and often feed on different prey – usually small fish, such as smelt in Lake Taupō. This may explain why rainbow trout are bold feeders, more easily caught than the wary brown trout. Rainbow trout may reach 750 millimetres and more than 10 kilograms in New Zealand. Fish of 600 millimetres and 2–3 kilograms are often caught, and fish weighing 4–5 kg are not uncommon. Most rainbows tend to live for four or five years, although individuals up to 11 years old have been recorded. Life cycle: Several hundred to several thousand eggs are laid in a small hole by the female and fertilised by the male. After 1–3 months the eggs hatch into alevins (fry with yolk sacs attached). These live in the gravel, feeding from their yolk sac. They then emerge as fry, about 25 millimetres long. By late summer they have reached 50–70 millimetres. As juveniles and spawning adults they live in streams, where they are exposed to predators on the banks. Adults usually run upstream from a lake to spawn in late winter and early spring, in headwater streams with gravel beds. Not all rainbow trout survive spawning."[150]

"Much of the central North Island winter fishing is centred on rainbow trout running upstream from Lake Taupō to spawn in tributaries such as the famed Tongariro River."[150]

"Rainbow trout are native to the westward draining rivers of North America and also to the Kamchatka Peninsula on the western side of the Pacific Ocean. Stock introduced into New Zealand were brought from North America as early as 1883. Although they were not as easy to establish as brown trout, self-sustaining populations of rainbow trout are now widespread in New Zealand and form the backbone of the popular and highly valued fisheries that occur in the lakes and rivers of the central North Island. They also support fisheries in many of the lakes along the eastern flanks of the Southern Alps in the South Island. Like other salmonids, the colour pattern of rainbow trout is variable. Lake-dwelling fish are generally uniformly silver with small, darker spots along the back, mainly above the lateral line. The backs of river dwelling fish are often more olive-green, and the red band, or rainbow, along the lateral line more prominent. When rainbow trout move into rivers and streams for spawning, this band intensifies in colour, and red slashes may occur on the cheeks and in the folds beneath the lower jaw. Rainbow trout can be distinguished from brown trout and Atlantic salmon by the presence of dark spots on the caudal (tail) fin, and from brook char and mackinaw by the absence of pale spots on their sides. Rainbow trout have a short-based anal fin compared to a long-based anal fin on sockeye salmon. Spawning chinook salmon also develop a red flush along their sides and hence can be confused with rainbow trout. However, chinook salmon have black gums whereas the mouth of rainbow trout is pale in colour. Most rainbow trout migrate to their spawning grounds, with both lake and river dwelling fish moving upstream to suitable locations, often in small tributaries. Here they may congregate in large schools just prior to spawning. In lakes without suitable spawning tributaries, spawning can occur along the lakeshore. The main spawning season for rainbow trout is June and July, but the season can be extended to October in some lakes, especially those in the colder regions of the North Island. Although there are no sea-run populations of rainbow trout in New Zealand (usually very large fish known in North American as steelhead), fish 500–600 mm in length and 2–3 kg in weight are the norm in most New Zealand populations. In lakes regarded as trophy fisheries, fish of 4–5 kg are caught regularly."[155]|-

Sockeye adult male.jpg Oncorhynchus nerka Sockeye salmon LC IUCN 3 1.svg Least concern[157] "Sockeye salmon (Oncorhynchus nerka): Sockeye were released into the Waitaki River catchment in 1902, after some 500,000 ova were gifted by the Canadian government. Young that hatched were released in the hope of yielding a returning run, to develop a commercial fishery based on canning salmon. The species established itself in Lake Ōhau but a sea-going population never developed. A remnant population still exists in Lake Ōhau and its tributaries."[153]

"Sockeye salmon stocks in New Zealand derive from a single importation of eggs that occurred in 1902. Although in their native North Pacific habitat most stocks are anadromous, stocks in New Zealand are wholly land-locked. Sockeye were released into the Waitaki River catchment, and were restricted to Lake Ohau for over 60 years where they were largely unknown to anglers. When Lake Benmore was established, this provided the sockeye with unusual but effective adult habitat, and during the 1970s stocks increased. However, when Ruataniwha Dam was completed in 1982, access to Lake Benmore was no longer possible, and today, apart from breeding populations on a couple of commercial salmon farms, sockeye salmon are virtually extinct. Sockeye salmon co-exist in the Waitaki catchment with chinook salmon and brown and rainbow trout. The black gums of the chinook salmon distinguish this species from the sockeye. Sockeye also have a long-based anal fin (see glossary), which can be used to tell them apart from the trout species. In North America, sockeye salmon support an important commercial fishery and are a splendid table fish with bright orange flesh. The land-locked stocks here do not grow as large as their anadromous northern counterparts and rarely exceed 1 kg in weight. Northern stocks also develop brilliant spawning colours, becoming bright red along the back and sides with a green head. These colours are much more subdued in the New Zealand stocks although a pink flush may develop along the sides of larger spawning fish. Spawning occurs in autumn and is confined to a brief period of 2–3 weeks."[158]

Chinook Salmon Adult Male.jpg Oncorhynchus tshawytscha Chinook salmon
Not assessed
"Chinook or quinnat salmon are native to North America and Asia, and were brought to New Zealand in the early 1900s. They are big, often weighing 10–15 kilograms. They spawn (breed) in tributaries of rivers on the east coast of the South Island, such as the Waitaki, Rakaia and Rangitātā. New Zealand is the only place in the world where they have been successfully released outside their native home. Some salmon habitats have been harmed because river water is taken to irrigate farms, and rivers have been dammed. This reduces salmon numbers. Young salmon swim out to sea, then after three or four years return upstream to spawn. Unlike trout, they die after spawning."[148]

"Chinook or quinnat salmon (Oncorhynchus tshawytscha) are native to the north-west coast of North America, and north-east Asia. New Zealand remains the only place in the world where Chinook salmon have become established successfully outside their natural range. In the early 1900s they were introduced from ova sourced from the McCloud River in California. They were released into the Hakataramea River, a tributary of the Waitaki River in the South Island. They were soon running up other Canterbury rivers such as the Rakaia and Rangitātā."[151]

"Chinook are the largest species of the Salmonidae family in New Zealand, commonly reaching 10–15 kilograms. Most adults are three years old when they spawn. When they enter river mouths on their spawning runs, they are very silvery in colour – but this gets duller the longer they stay in fresh water. Salmon are found mainly on the South Island’s east coast, from the Waiau River in North Canterbury to the Clutha River in South Otago. There are also small runs in the Paringa, Taramakau and Hokitika rivers on the West Coast. The renowned fisheries are the Waitaki, Rangitātā, Rakaia and Waimakariri rivers. Once, smaller rivers such as the Ashburton and Ōpihi also supported salmon. Taking water for irrigation has seen these rivers suffer from river mouth closure in summer. In the 2000s they were no longer regarded as good salmon fisheries. Small landlocked Chinook salmon can also be caught in some South Island lakes such as Lake Wakatipu. Dams on the Clutha River prevent them migrating to sea, so they never grow to any great size (they are typically less than 1 kilogram). Occasionally stray salmon are found in North Island rivers."[151]

"Chinook salmon are one of three Pacific Salmonidae from the genus Oncorhynchus that has become established in New Zealand. Native to the northwest coast of North American and northeast Asia, the specific name of this fish (pronounced shaw-witch-shaw) comes from the Kamchatka Peninsula and is thought to refer to their distinctive black gums. This character can be used to distinguish chinook salmon from the other Salmonidae in New Zealand. This species is also known as quinnat or king salmon. Chinook salmon in New Zealand have a life cycle that is typical of salmon in the North Pacific. The adults grow to maturity in the sea and migrate upstream to spawn, usually when they are three years old. After spawning, which occurs in autumn, all of the adults die. Juveniles hatch in spring, and typically spend 3 months in fresh water before migrating downstream to enter the ocean in summer. In some populations, a second downstream migration, consisting of individuals that have spent a year in fresh water, occurs the following spring. Chinook salmon are a highly prized sports fish in New Zealand although the population is not large enough to support commercial fishing. However, there are a number of successful salmon farms in New Zealand, and it is possible to buy fresh chinook salmon in most supermarkets nowadays. When the spawning migration of adult fish is in progress between December and April, picket lines of eager anglers are a common sight at major river mouths along the east coast of the South Island. Salmon lose condition as they migrate upstream and thus the most prized fish are those caught soon after arrival in fresh water. Chinook are the largest Salmonidae in New Zealand, commonly reaching 10–15 kg in weight. Chinook salmon occur mainly on the east coast of the South Island from the Waiau River in the north to the Clutha River in the south. The main runs occur in the large braided rivers – the Waimakariri, Rakaia, Rangitata and Waitaki. There are also small runs in the Paringa, Taramakau, and Hokitika River on the west coast, but other records of Chinook salmon on the west coast are probably stray fish. A few land-locked stocks are also known from lakes along both the east and west coasts. Although juvenile fish have been caught in some North Island rivers, indicating successful spawning had occurred, there are no consistent runs of Chinook salmon in the North Island."[160]

Salmo salar.jpg Salmo salar Atlantic salmon LC IUCN 3 1.svg Least concern[162] "Atlantic salmon (Salmo salar): The Atlantic salmon is native to rivers draining to the North Atlantic Ocean. Early settlers from Britain were familiar with the fish and eager to establish sea-going salmon populations. Between 1864 and 1910, 24 introductions were attempted involving 5 million ova, but with very little success. There were local fisheries at Lake Te Anau and Lake Manapōuri and in the Waiau River in the 1920s and 1930s, but the fish were poorly conditioned and did not swim out to sea. They weighed only about 2 kilograms, whereas Atlantic salmon in Britain returning from the sea were typically four times that weight. The species is considered to be close to extinction in New Zealand, with remnant wild stocks confined to lakes in Southland’s upper Waiau catchment."[153]

"As its name implies, the Atlantic salmon is native to the continents bordering the Atlantic Ocean in the Northern Hemisphere. There, it is a highly prized sports fish renowned for its large size and fighting abilities. Although early settlers in New Zealand were eager to establish Atlantic salmon populations here, most introductions were not successful and feral stocks are confined to the upper Waiau River catchment where it is considered to be close to extinction. Breeding stocks of Atlantic salmon are maintained at the Otago Fish and Game Council hatchery in Wanaka. Atlantic salmon closely resemble brown trout, but are a more slender, elongate fish. The caudal peduncle is also longer; if the anal fin is folded up against the body, it does not reach the base of the caudal fin. Atlantic salmon have dark backs, fading to a silvery colour below the lateral line. The back and sides are covered in small, darker spots but these generally do not extend below the lateral line. There are no spots on the tail. In their native waters, adult Atlantic salmon live in the sea and migrate to their freshwater spawning grounds in winter. Unlike the Pacific salmon species, Atlantic salmon can spawn more than once. In New Zealand most adults reside in lakes and migrate upstream for spawning. Spawning here also occurs in winter."[163]

Bachforelle Zeichnung.jpg Salmo trutta Brown trout LC IUCN 3 1.svg Least concern[165] "Brown trout were brought in during the 1860s and quickly spread into the rivers and lakes. With plenty of native fish to eat, the trout grew fat – weighing up to 10 kilograms. Today, most brown trout caught by fishermen weigh 1–2 kilograms. They prefer cooler water and live in rivers, lakes and estuaries south of the Coromandel Peninsula. They hide under rocks or streamside plants, and are difficult to catch. Their colours change with the habitat. Brown trout that swim out to sea are bright silver, those in lakes are dull silver, and those in rivers are golden brown. All have black spots. They usually live for eight to ten years."[148]

"Brown trout (Salmo trutta) form the basis of most freshwater fishing in New Zealand. From the late 1860s brown trout, from Europe, were introduced throughout New Zealand for fishing. They established themselves rapidly where they were released – and also spread by going out to sea and swimming up other rivers. In the early years they were very well conditioned. Some were so fat they looked like rugby balls, and could weigh over 10 kilograms. After the initial boom, average trout sizes dropped. Acclimatisation societies had set up hatcheries and continued to release small fish into the rivers for decades. The rationale was that there was competition from predators such as eels and shags, but research has since shown this to be a waste of effort, as natural spawning provides more than enough young fish."[149]

"Brown trout live mainly in rivers, but are also found in diverse habitats from estuaries to subalpine lakes. Brown trout are predatory fish that eat small aquatic insects and small fish. In flowing water they tend to face upstream, feeding on drifting aquatic insects. In slow-moving pools, brown trout cruise looking for food. In lakes they cruise the shallow zone close to shore, feeding on small fish such as bullies, and invertebrates such as dragonfly nymphs and snails in weed beds. Brown trout often hide under rocks and streamside vegetation, and immediately seek cover if they see movement on the riverbank. As a result, they are one of the most difficult freshwater fish to catch. The body form and behaviour of brown trout are adapted for living in rivers. For example, their pectoral fins are much larger than those of rainbow trout. This allows them to use the river flow to hug the riverbed, where the current is slower and it takes less energy to stay in the feeding position. In New Zealand brown trout often reach 800 millimetres and 5 kilograms. Most fish caught by anglers are smaller – typically 1–2 kilograms."[149]

"Brown trout are found south of the Coromandel Peninsula. They prefer lower summer water temperatures than rainbow trout do, and winter water temperatures over 11°C kill brown trout eggs. Life cycle: The female lays several hundred to several thousand eggs in a small hole. These are fertilised by the male. After a month or two the eggs hatch, and the fry live in the gravel before emerging and feeding along stream margins. Adults spawn in early winter, usually in the headwaters of streams with gravel beds. Adults usually survive spawning and spawn annually. Brown trout live for 8–10 years, although individuals up to 15 years old have been recorded in New Zealand."[149]

"Brown trout are native to Europe and were first introduced into New Zealand in the late 1860s from British stock that was first established in Tasmania. Many subsequent introductions have occurred, and brown trout are now the most widespread and common introduced fish in New Zealand waters. Brown trout have been introduced to at least 40 other countries worldwide, including Australia, South Africa and countries in South America. The colour pattern of brown trout varies with their habitat. Sea-run and lake fish tend to be silvery with brown and olive spots of varying intensity, whereas river-dwelling fish are darker with dark brown and red spots, the latter being surrounded by paler halos. These red spots are particularly prominent on small river fish. Brown trout seldom have any spots on their tails, a feature that distinguishes them from rainbow trout. Brown trout closely resemble the Atlantic salmon and both occur in the Lake Te Anau system. Brown trout are generally stockier, and have a deeper and shorter caudal peduncle than Atlantic salmon. They also have a shorter-based and deeper anal fin than chinook or sockeye salmon. Brown trout are primarily a freshwater species, but can spend time in the sea. One specimen that was tagged near Christchurch was later recaptured in the Mataura River, while another tagged in the Wanganui River system turned up in Taranaki 125 days later. Spawning, which occurs in autumn and early winter, takes place in fresh water. Brown trout do not undertake extensive spawning migrations like some of the other salmonids, but some movement does occur, particularly for lake populations. Like all salmonids, the female digs a redd where the eggs are deposited. Although the brown trout fishery does not receive as much publicity as that for rainbow trout, these fish are highly prized by anglers because they are considered much harder to catch. Specimens up to 14 kg in weight have been recorded in recent times, but a fish over 5 kg would cause any angler to smile. Brown trout occur virtually everywhere in New Zealand south of Auckland. Populations in the northern North Island are limited because winter water temperatures are probably too warm for successful egg development. Although brown trout have spread to Fiordland, they have not become established on Chatham or Stewart Islands."[166]

Brook trout 1918.jpg Salvelinus fontinalis Brook trout
Not assessed
"Brook char (Salvelinus fontinalis): Brook char were first introduced in the late 1870s or early 1880s. They were widely released, but it seems they could not compete with brown trout. They still exist in headwaters of some catchments, such as the upper reaches of the Shag River in Otago, but they are usually very small (typically only 150 millimetres). Lake Emily, inland from Ashburton, is the best fishery, where brook char up to 600 millimetres and 3 kilograms may be caught."[153]

"This native of the eastern North American continent was first introduced to New Zealand in the late 1870s or early 1880s. Brook char have been released in virtually all the main catchments on the east coast of the South Island, and they were also widely introduced in the North Island although they now occur in only 3-4 rivers in the Central North Island. Although many populations have now become established in the South Island, river-dwelling brook char are confined to the very small tributaries where they do not have to co-exist with other salmonids. Here they can reach maturity, but they tend to be stunted (small in size) and thus are not usually fished for. Several lake populations have also become established, and these are more popular with anglers. In particular, Lake Emily in the Ashburton River catchment yields brook char up to 2 kg in weight. Brook char are an attractive, brightly coloured member of the Salmonidae family. In fact their colouration is a good characteristic to use to distinguish them from the other salmonids. Their bodies are generally dark with marbling present on the back. Their sides are covered with gold and red spots, the latter of which are surrounded by pale blue halos. In addition, there is a distinctive white stripe followed by a contrasting black stripe on the leading edge of the pelvic, pectoral and anal fins. Brook char also have a very large mouth that extends back behind the posterior margin of the eyes."[168]

Lake Trout GLERL.jpg Salvelinus namaycush Lake trout
Not assessed
"Lake char or mackinaw (Salvelinus namaycush): The mackinaw is native to northern North American lakes, where it can grow up to 46 kilograms. The only New Zealand population occurs in Lake Pearson, in the headwaters of the Waimakariri River. The species arrived in 1906 and was destined for Lake Kaniere on the West Coast. But as they were being transported towards Arthur’s Pass, the temperature of the water containing the fish rose too high. Fearing that the mackinaw would die, the acclimatisers dumped them in nearby Lake Pearson and Lake Grassmere. A population still exists in Lake Pearson, but the typical weight of less than 1 kilogram suggests that it is not an ideal habitat. In New Zealand mackinaw are little more than a curiosity."[153]

"This member of the Salmonidae family occurs naturally throughout the north of the United States and in Canada and Alaska. A single importation of eggs occurred in 1906, and these fish were destined for Lake Kaniere on the west coast. However, when their transport ran into difficulties crossing Arthurs Pass, the fish were dumped into Lakes Grasmere and Pearson in the Waimakariri River catchment. Mackinaw have not thrived in New Zealand, and the only known population at present occurs in Lake Pearson. In Lake Pearson, mackinaw co-exist with rainbow and brown trout. They can be distinguished from the trout species by the presence of pale yellow-green spots on the back and sides. The mouth is also very large and the caudal fin quite deeply forked. Mackinaw are one of the few salmonid species that do not dig redds. It is believed that the adults use their tails to sweep mud and silt from gravels along the lakebed and that the eggs are then released over the clean gravels where they sink in among the rocks. Spawning probably occurs in April and May. Overseas, mackinaw are known as a cold-water fish that generally live in deep lakes. It is therefore unusual that they survive in the small and shallow Lake Pearson. Known variously as lake trout, lake char and mackinaw, in their native waters mackinaw grow to a very large size – up to 46 kg in weight. In New Zealand they rarely exceed 1 kg in weight and are often in poor condition when caught, indicating that Lake Pearson is not ideal habitat for them. Due to their restricted distribution, small size, and sluggish response when hooked, mackinaw are not highly regarded by anglers in New Zealand."[170]

Other reading[edit]

  • Fishing in New Zealand
  • NIWA Atlas of NZ Freshwater Fishes
  • Hayes, John, and Les Hill. The artful science of trout fishing. Christchurch: Canterbury University Press, 2005.
  • Millichamp, Ross. Salmon fever: a guide to salmon fishing in New Zealand. Christchurch: Shoal Bay, 1997.
  • McDowall, R. M. The Reed field guide to New Zealand freshwater fishes. Auckland: Reed, 2000.

Coarse fish[edit]

"Coarse fish are freshwater fish other than trout or salmon. They are called coarse fish because their scales are usually larger and coarser than those of trout or salmon. They were introduced in the late 1800s and early 1900s by British settlers, for aquariums or fishing. Many have been illegally set free by anglers wanting to stock up rivers and lakes.[171]

Types of coarse fish[edit]

"Coarse fish found in New Zealand are:

  • Cyprinidae family – goldfish, koi carp, tench, rudd, orfe, gudgeon, grass carp, silver carp
  • Poeciliidae family – gambusia, caudo, common guppy, sailfin molly, swordtail
  • Percidae family – European perch
  • Ictaluridae family – brown bullhead catfish.

Most belong to Cyprinidae, a family which contains almost 2,500 species, including carps, minnows, and a host of other small fish found across Europe, Asia, Africa and North America."[147]

Coarse fishing[edit]

"Coarse fish are caught by anglers with a baited hook attached to a float. Some species have been illegally introduced and spread by anglers wanting to fish for them. Some species such as goldfish are usually too small to be targeted by anglers. Some very keen coarse anglers aim to catch a variety of species or the largest fish species. A few species, including silver carp and grass carp, do not breed naturally in New Zealand waterways and populations are maintained by releasing fish reared in captivity. It is doubtful whether some species, such as caudo, are established at all, despite records of their presence in New Zealand."[147]

Legal status[edit]

"Introduced fish can have four statuses under various pieces of legislation:

  • sports fish (e.g. perch, tench) – it is an offence to fish for them without a licence.
  • noxious fish (e.g. koi carp, rudd) – illegal to possess, breed or release under the Freshwater Fisheries Regulations 1987.
  • unwanted organism (e.g. koi carp, gambusia) – illegal to release, spread, sell or breed under the Biosecurity Act 1993.
  • restricted species (e.g. silver carp, grass carp) – releases require the approval of the minister of conservation.

Offenders can attract a maximum sentence of five years and/or a fine of up to $100,000. The legal status of some species varies. For example, rudd is only a ‘sports fish’ in the Auckland–Waikato fish and game region, but a ‘noxious fish’ elsewhere. Some species, such as caudo, goldfish and orfe, have no legal status."[147]

Value or pest?[edit]

"Some coarse fish are valued as food (European perch), or for recreational angling (European perch, koi carp, rudd, tench). Some have adverse effects on ecosystems (koi carp, rudd, tench, gambusia), while others are valued for their use in biological control (grass carp and silver carp). When ‘noxious fish’ or ‘unwanted organisms’ are found in contained areas such as ponds or small lakes, authorities sometimes eradicate them using the natural toxin rotenone, known as Derris Dust to gardeners."[147]

Morihana on horseback[edit]

"Sub-inspector Morrison of the Armed Constabulary released goldfish into Lake Taupō in 1873, after bringing the fish on horseback from Napier. Goldfish became known to Māori as morihana – a transliteration of Morrison’s name. For some time morihana were a food for Rotorua Māori."[172]

Introduced and naturalised: Coarse fish
Family Image Scientific name Common name Fish-
base
IUCN status Comments
Cyprinidae Cyprinidae is the carp or minnow family. It includes the carps, the true minnows, and their relatives such as the barbs and barbels.

"The Cyprinidae family is one of the largest of the freshwater fish families with about 1450 known species. None are native to New Zealand, but several species have been introduced here. Generally carp have large scales, small barbels around their mouth, and no adipose fin. There are many exceptions to this, however, as might be expected in such a large family. Cyprinids have been cultured as a food fish for thousands of years in their native countries. No such industry exists in New Zealand, although two of the species listed above, grass and silver carp, were brought here as potential aquatic plant or algal control agents. Neither of these species has established feral stocks here, but the other carp species have, although the precise status of orfe is uncertain. With the exception of goldfish, rudd and tench, the carps are confined to the North Island in New Zealand. None have spread to Chatham or Stewart Island. Most of the carp species in New Zealand have no teeth and so as adults they feed mainly on plants and algae. However, juvenile fish will eat small animals such as snails. Spawning occurs during summer and carp prefer aquatic vegetation as an egg laying substrate. Because of their feeding and spawning requirements, carps tend to be found in warm, weedy waters in lakes and slow-flowing rivers."[173]

Shubunkin goldfish.jpg Carassius auratus Goldfish LC IUCN 3 1.svg Least concern[175] "Goldfish (Carassius auratus) were imported early after Europeans settled in New Zealand, although exactly when is uncertain. They were probably introduced by aquarists and pond-keepers as an ornamental species. They were liberated into wild habitats such as Lake Taupō and Lake Rotorua in the 1870s, and by the 2000s were widespread, mostly living in ponds and small lakes, and probably harmless."[172]

"Goldfish were first brought to New Zealand in the late 1860s. Aquarists and breeders carried out further introductions and goldfish are now widespread and well established in the North Island. Their South Island distribution is more restricted, but recent surveys by the Department of Conservation have shown that they are in Nelson, central Otago, Southland and the West Coast. In the early 1900s, feral goldfish populations in central North Island lakes were important to the Maori as a food fish."[176]

Grass.Carp2web.jpg Ctenopharyngodon idella Grass carp
Not assessed
"Grass carp (Ctenopharyngodon idella) and silver carp (Hypophthalmichthys molitrix) were introduced for biological control. It is unlikely either species will reproduce in the wild – all populations were established and are maintained by hatchery production. These carp grow to several kilograms in weight, and are found intermittently around the country. Grass carp eat large, leafy aquatic plants and in doing so they help control excessive plant growth in ponds and drainage ditches, reducing the need to spray water weeds or use draglines to clean drains. Silver carp eat phytoplankton (small, single-celled algae that make the water in ponds green and turbid), and were imported to help control it. However, their effectiveness is unproven."[172]

"Grass carp were first brought to New Zealand in the 1960s because of their potential to control the growth of aquatic plants. Unlike the other introduced fish brought to New Zealand, the potential value and impact of grass carp was investigated in secure facilities prior to their use in field trials. Although these fish mature, they have extremely specific spawning and rearing requirements and the establishment of a wild population is extremely unlikely. There has been much controversy surrounding the use of grass carp as a weed control agent in New Zealand. So far, the main value of grrass carp in New Zealand has been to eradicate problem weed species from lakes, thus allowing native plant communities to re-establish. This means they have a role to play in lake restoration, as well as weed control, but their use for weed control in drains is still being investigated. Today, stocks of grass carp are maintained for breeding at a private hatchery north of Auckland. Grass carp are a large and robust fish. They commonly exceed 500 mm in length, 10kg in weight, and can live for 15-20 years. Their backs are a dark bronze colour, but this gradually fades to silver on the belly. The margins of their large scales are outlined in a darker colour, giving them a crosshatched appearance. Grass carp have no barbels, but can be distinguished from goldfish by the short dorsal fin with only 7–9 rays."[178]

Cyprinus carpio.jpeg Cyprinus carpio Wild common carp/Koi carp VU IUCN 3 1.svg Vulnerable[180] "Koi or European carp (Cyprinus carpio) were brought to New Zealand in the 1800s, but did not become established in the wild until the 1960s, when ornamental koi were released. They are now abundant in the lakes of the lower Waikato, and present in some other areas, especially the north. Globally koi carp are a problem. They churn up the beds of wetlands while searching for food, causing environmental deterioration. In New Zealand koi are classed as a ‘noxious fish’ and an ‘unwanted organism’, making their possession unlawful. Nevertheless, they are a target of recreational coarse fishers (who are illegally spreading the fish around the country), because of their size (10 kilograms or more) and fighting ability. Bow hunters look for koi carp in the Waikato wetlands."[172]

"Koi carp: This brightly coloured member of the Cyprinidae family is a variety of the common carp. The common carp is native to Asia, although it has been introduced so widely and for so many centuries that its precise origins are uncertain. Today, it occurs on every continent except Antarctica. It is not known whether the introduction of koi carp here was deliberate or accidental, but feral breeding stocks were first noticed in the Waikato in 1983. They are now common throughout the lower Waikato system, and have been spread mainly into ponds throughout the North Island. The first South Island record of koi carp occurred in Nelson in 2000, but most of the South Island populations have now been successfully eradicated. Wild common carp tend to be an olive green colour, but the New Zealand stocks are derived from the highly bred ornamental Japanese koi and thus can exhibit a calico pattern of black, red, orange, gold and white blotches. So far, our feral stocks have not reverted back to the wild colouration. Although their colour pattern is a useful distinguishing characteristic, they also have two pairs of barbels that the other Cyprinidae found here lack. Koi eat a wide variety of organisms, including both plants and animals. One way they feed is by sucking up and expelling material from the bottom, filtering out edible material as they do so. This habit means that, at high densities in shallow lakes, they can greatly increase the turbidity of the water because they are constantly disturbing the substrate.This makes waterways unattractive and reduces the abundance of aquatic plants. In other countries, common carp have caused such an increase in turbidity that vast amounts of money and effort have been spent trying to eradicate them; unfortunately these have largely been unsuccessful. Although similar problems have not yet been documented in New Zealand, the spread of this fish should certainly be minimised."[181]

LeuciscusIdusWindeIde56cm 21-4-2009 16-46-58.JPG Leuciscus idus Ide/Orfe LC IUCN 3 1.svg Least concern[183] "Orfe (Leuciscus idus) and gudgeon (Gobio gobio) were introduced illegally with a view to establishing populations for anglers. Orfe possibly occur in a single lake near Auckland, although it is uncertain if they are still present. Gudgeon became established in another Auckland pond. Once discovered, attempts were made to exterminate them, and as far as is known, there are now no gudgeon in New Zealand."[172]

"This member of the Cryprinidae family is native to northern Europe where it is valued as a coarse angling fish. Orfe eggs were illegally imported to New Zealand by mail sometime in the 1980s. Subsequent releases occurred between 1985–86 in at least 8 and possibly 5 more sites north of Auckland. The current status of these populations is in doubt; some believe orfe failed to survive in at least 7 of these sites while others are less certain. At least one release site remains unknown and it seems likely that orfe persist in the wild in at least one location in New Zealand. In Europe, wild orfe are usually greyish brown with silver bellies. However, the variety of orfe present in New Zealand (the golden orfe) is derived from ornamental pond stocks and thus closely resembles rudd. Although it is not known if the two species co-exist, on orfe the scales are smaller and the fins more orange than red coloured. Rudd also have a small projection at the base of their pelvic and pectoral fins. Eventually, the orfe’s golden colouration may revert to the wild type. Little is known about the biology of orfe in New Zealand. In Europe they primarily inhabit slow-flowing waters. Their food consists of aquatic invertebrates such as worms and snails, but large orfe may consume other fish and aquatic vegetation. Like the other Cyprinidae, orfe are prolific breeders and large females may contain tens of thousands of eggs. Whether they become a nuisance species in New Zealand or will be successfully eradicated remains to be seen."[184]

Scardinius erythropthalmus 2009 G1.jpg Scardinius erythrophthalmus Common rudd LC IUCN 3 1.svg Least concern[186] "A fish of ponds and lakes, rudd (Scardinius erythrophthalmus) were smuggled into New Zealand in the 1960s and liberated quite widely – illegally and to provide game for sport (they can reach 2 kilograms). They are common in the hydro lakes of Waikato. Concerns about their potential adverse effects on the environment have led to their classification as ‘noxious fish’, except in the Auckland/Waikato fish and game region, where they are ‘sports fish’ and a licence is needed to fish for them."[172]

"This member of the Cyprinidae family is native to Eurasia and was illegally imported to New Zealand in 1967. Stock bred from this importation was subsequently widely released and rudd are now well established in many North Island waterways, particularly in the Waikato River catchment. Rudd have also been recorded around Christchurch, and more recently from other parts of the South Island. Like goldfish, rudd do not have any barbels around their mouth, a feature that tells them apart from koi. They can be distinguished from goldfish because they lack the stout spines on the front edge of the dorsal fin, and from orfe by the projections that occur at the bases of their pectoral and pelvis fins. Rudd can also be confused with perch, but perch have two dorsal fins, the first with several firm spines. Rudd are darker on their backs than on their bellies and have bronze highlights when the light catches their scales. Their fins are usually bright reddish orange. Juvenile rudd are planktivorous, but as adults their diet consists mainly of aquatic plants. As a herbivore, rudd are likely to have a role in supressing the regeneration of aquatic plants in lakes and hence in maintaining poor water quality. A high-density rudd population ruined the trout fishery in an Auckland lake becuse they outcompeted trout for anglers lures. This suggests their introduction into new waters could be detrimental to fish and native plant communities as well as to water quality. Like all the Cyprinidae, rudd are prolific breeders and large females can produce literally hundreds of thousands of eggs. The largest rudd ever recorded was over 400 mm in length, but fish 200–250 mm in size are much more common."[187]

Tinca tinca Prague Vltava 2.jpg Tinca tinca Tench LC IUCN 3 1.svg Least concern[189] "Tench (Tinca tinca) were introduced by acclimatisation societies in the 1870s. They lived mainly in some North Otago waters, and did not become widespread or abundant for many decades. Recently, anglers and others have spread tench more widely – often illegally (it is illegal to liberate fish into new waters without approval from the minister of conservation). Tench appeal to coarse fishers because they grow large, are powerful swimmers, and a challenge to catch. In the early 2000s they were widespread, mostly in small lakes. They are classed as ‘sports fish’, so a licence is needed to fish for them."[172]

"This member of the Cyprinidae family is native to Europe and was first introduced to New Zealand in 1867. Although imported as a sports fish, there has been little angler interest in tench until recently. Tench grow to a large size in New Zealand, and some northern lakes have now gained an international reputation among anglers who prefer fishing for coarse fish. Fish over 2 kg in weight are not uncommon, and in some instances 4-kg fish have been caught. Tench are generally an olive green colour although this varies from dark to light. There is a single small barbel at each corner of the mouth. The fins tend to be thick and fleshy and the body is covered in small scales. Their eyes are bright orange, and this is their most distinctive characteristic. The biology of tench in New Zealand has not been studied, but is probably similar to that of fish in their native waters. Tench generally live in still or slow-flowing waters and are carnivorous, feeding mainly on crustaceans, molluscs and insect larvae. Males have longer and fatter pelvic fins than females. Spawning occurs in spring and summer and, like all the Cyprinidae, tench are prolific breeders; a large female may produce hundreds of thousands of small eggs. Although most fishing for tench occurs in the Auckland area, tench are also present in some lakes and ponds in Northland, Tauranga and Wellington. They have been present in the South Island near Oamaru for many years, but have also been found recently in Nelson, Marlborough and Canterbury during recent surveys by the Department of Conservation. A golden variety of tench, which is bright yellow-orange, is thought to be present in some small lakes and ponds near Auckland. This variety of tench was illegally imported in about 1980."[190]

Gobiidae Arenigobius bifrenatus Bridled goby
Not assessed
[192]
Ictaluridae Ameiurus nebulosus.jpg Ameiurus nebulosus Brown bullhead (catfish) LC IUCN 3 1.svg Least concern[194] "North American brown bullhead catfish (Ameiurus nebulosus) were introduced for unknown reasons in the 1870s. They became abundant in the lower Waikato River, and were not found elsewhere for many decades apart from small numbers in Lake Māhinapua, near Hokitika, the only confirmed South Island population. Their range increased from the 1980s – perhaps spread by commercial eel fishers who caught them in their fyke nets (large, funnel-shaped nets that trap fish). Intermittent catfish populations are now widespread in northern waters, including Lake Taupō, although how they reached this lake is uncertain. They have spread from Lake Taupō to the series of hydro lakes in the Waikato River."[195]

"The catfish is not native to New Zealand and is the only member of the Ictaluridae family that occurs in New Zealand waters. The Ictaluridae, or North American catfish, is one of the smallest of more than 30 catfish families worldwide with about 45 species. Ictalurids are characterised by having barbels around the mouth – these look rather like whiskers and hence the common name catfish. However in North America, where there are many species of catfish, the species found in New Zealand is known as the brown bullhead. The brown bullhead catfish is dark brown to olive green colour with paler sides and bellies. In addition to the eight distinctive barbels around their mouth, catfish also have relatively small eyes and a smooth skin. The leading edge on their dorsal and pectoral fins has a sharp spine, and thus catfish should be handled very carefully to avoid injury from the spine. Catfish are an extremely robust fish and can survive for long periods out of water. They commonly grow to 200–300 mm in length. Catfish have been present in New Zealand since the late 1800s. For many years, they were rarely encountered with the only known populations occurring in the lower Waikato River and in Lake Mahinapua south of Hokitika. They were first recorded from Lake Taupo in 1985. Since then, catfish have gradually spread throughout Lake Taupo and down the Waikato River. In 1997, catfish were recorded for the first time from the Kaituna Lagoon near Lake Ellesmere, and in 2003 from a stream entering Hokianga Harbour. Accidental introductions via boat trailers and especially fyke nets used for eeling is continuing to spread this species around New Zealand. Catfish spawn in shallow depressions on the substrate in the shallows. The male guards and fans the eggs during development, and also guards the larvae for about a week after hatching. Catfish are carnivorous and use their sensitive barbels to probe the substrate and locate insects, crustaceans, molluscs and small fish. Freshwater crayfish are a major prey species for catfish in Lake Taupo."[196]

Percidae Perca fluviatilis 1879.jpg Perca fluviatilis European perch LC IUCN 3 1.svg Least concern[198] "European perch (Perca fluviatilis) are a desired angling species, brought to New Zealand in the late 1860s. They are classed as ‘sports fish’, so anglers need a licence to fish for them. Perch are widespread but intermittent around the country. Concentrated populations are in the western and southern North Island, around Hokitika, and in the eastern and southern South Island. The fish has firm, white, tasty flesh, and is much the best eating of the exotic non-salmonid species."[195]

"Redfin perch belong in the Percidae family, a family of about 60 species that are native to the Northern Hemisphere. One species has become established in New Zealand and it is known simply as the perch. New Zealand perch come from Tasmanian stocks that were originally imported from England. They have become well established in Otago and Southland, but also occur in many other parts of New Zealand, especially around Auckland, the Waikato and in North Island west coast lakes south of New Plymouth. Perch can be distinguished from other species by the presence of the two dorsal fins, the first having 13–17 firm sharp spines. There is also a broad flat spine on the gill cover. Perch have six or more dark bands along their sides; these are most prominent in small fish. The bottom edge of the caudal fin is bright red-orange, as are the anal and pectoral fins. These features make perch easy to recognize. Although perch were liberated widely in the late 1870s, there was little interest in their angling potential until after 1990. They are a fine table fish with firm white flesh, but their small size and lack of fighting ability meant that they never became as popular with anglers as the salmonids. Perch are suitable game fish for youngsters because they are relatively easy to catch. Most perch in New Zealand are between 1–2 kg in weight. Perch prefer slow-flowing and still water habitats. They are strictly carnivorous and adults feed mainly on other fish. Perch have been shown to reduce the abundance of common bullies in lakes. They also reduce inanga, smelt and crayfish in lakes where they have been introduced. At high densities, small fish predominate and can cause toxic cyanobacterial blooms."[199]

Poeciliidae Poeciliidae include live-bearing aquarium fish, such as the guppy, molly, platy, and swordtail. "A group of exotic species belongs to the family Poeciliidae, sometimes known as the livebearers because they give birth to live young rather than lay eggs. There are five small livebearers in natural habitats in New Zealand – one (gambusia) was introduced for biological control, the others for aquariums."[195]

"As the common name of this family implies, the Poeciliidae are characterised by giving birth to live young. Other family characteristics include a single soft-rayed dorsal fin and no lateral line. On male poeciliids, the anal fin has evolved into a structure known as a gonopodium that is used to transfer sperm bundles to the female fish. Poeciliidae are generally small; less than 100 mm in length, and usually the female is much larger than the male. The Poeciliidae are native to the Americas, extending from the upper Mississippi valley through Central America down to Argentina. There may be up to 300 species in this family and many are popular with aquarists. Five species have been introduced to New Zealand but only gambusia is widespread. The other members generally require warm water habitats, and are mostly confined to thermal areas in the central North Island."[200]

"In addition to mosquitofish, there are four other species of Poeciliidae in New Zealand. As all of these have a very restricted distribution, they have been combined for this discussion. They are all popular aquarium species (who has not heard of the guppy) and probably came to be released by aquarists either tired of looking after their fish or eager to establish feral populations in New Zealand. All except the caudo require warm water, and thus are unlikely to spread from their current locations in geothermal waters of the central North Island."[201]

Mosquitofish.jpg Gambusia affinis Mosquitofish LC IUCN 3 1.svg Least concern[203] "Gambusia (Gambusia affinis) were introduced, probably in the 1930s, in the hope they would help control mosquitoes. This is unproven in New Zealand, and they may be no more useful than native fish. Gambusia have become increasingly widespread since the 1980s, and are now common from the Waikato and Bay of Plenty northwards. A few populations have been reported in the northern South Island, where efforts have been made to exterminate them as they may be detrimental to native fish."[195]

"Gambusia or mosquitofish have been introduced to many countries to combat mosquitoes – they eat the larvae and pupae. They were first released in New Zealand in the 1930s. In a number of countries they have become pests by competing with native fish, and in New Zealand they are classed as an "unwanted organism" under the Biosecurity Act 1993."[204]

[205]

Gefleckter Kaudi Männchen.jpg Phallocerus caudimaculatus Speckled mosquitofish
Not assessed
"Resembling gambusia, caudo (Phalloceros caudimaculatus) have been reported from waters around Whāngārei, but it is uncertain if there are wild populations. Aquarists have stocks that could become established if released into suitable habitats."[195]

"Caudo (Phallocerus caudimaculatus) Caudo were only recently discovered in New Zealand. The only known population occurs in stock water troughs near Whangarei, but the origins of this population are a mystery. They are thought to have come from a nearby stream, but no population can be found there today. The discovery of yet another illegally introduced fish in New Zealand is of concern because it is unknown what impact these fish might have on the ecology. Caudo do not require particularly warm water, and thus could easily spread to other parts of Northland."[201]

Poecilia latipinna.jpg Poecilia latipinna Sailfin molly LC IUCN 3 1.svg Least concern[208] "Three poeciliids liberated into the wild by aquarists now live in geothermally heated waters in the central North Island. The common guppy (Poecilia reticulata) has been found in streams near Reporoa, the sailfin molly (Poecilia latipinna) in a wetland at the southern end of Lake Taupō, and the swordtail (Xiphophorus helleri) in a stream near Taupō. None of these species is likely to become established in waters of normal ambient temperature, so their geographical range will be restricted. Some were once in the Waipāhīhī Stream, near Taupō, but when water flows were manipulated, temperatures rose and the fish died out."[195]

"Sailfin molly (Poecilia latipinna) As its name implies, the sailfin molly has a large dorsal fin. In male fish this can be twice as high as their body. Sailfin molly are only found at the southern end of Lake Taupo in the warm geothermal swamps around Tokaanu and Waihi, but are quite abundant there. Sailfin molly are one of the largest poeciliids in New Zealand with female fish known to reach 120 mm."[201]

Guppy1trasp.png Poecilia reticulata Guppy
Not assessed
"Guppy (Poecilia reticulata) Guppies are restricted to warm geothermal waters near Reporoa where they have probably been present since the 1920s. They closely resemble mosquitofish, although the male is more brightly coloured. Reaching a maximum length of 60 mm, guppies mature just a few weeks after being born. Like many live bearers, the female guppy can use sperm from one copulation to produce several broods of young."[201]
Xiphophorus helleri 03.jpg Xiphophorus helleri Green swordtail
Not assessed
"Swordtail (Xiphophorus helleri) Feral swordtail in New Zealand are bright orange on the back and sides, a feature that distinguishes them from the other Poeciliidae. The lower part of the caudal fin in male swordtail is elongated into a tapering sword-like projection, hence the common name. They were probably only released in the last 15 years or so, and may eventually revert to the olive-brown colour typical of wild populations. They are only known to occur in Waipahihi Stream near Taupo. A survey of this stream in 1999 failed to catch any swordtail, and this population may now be extinct."[201]

External links[edit]

The status and exploitation of non-salmonid exotic fish in New Zealand

"The first effort to introduce fish into New Zealand was made in 1864 when a private individual tried to import 15 species of British..."

invasive species
  • Dean, T. (2001). "Invasive freshwater fish in New Zealand: DOC’s present and future management". In Managing invasive freshwater fish in New Zealand. Proceedings of a workshop hosted by Department of Conservation, pp. 59–69. ISBN 0478224230.
  • Chadderton, W. L. (2001). "Management of invasive freshwater fish: striking the right balance". In Managing invasive freshwater fish in New Zealand. Proceedings of a workshop hosted by the Department of Conservation, pp. 59–69. ISBN 0478224230.
  • de Winton, M., Dugdale, T., & Clayton, J. (2001). "Coarse fish: the demise of plants and malaise of lakes". In Managing invasive freshwater fish in New Zealand. Proceedings of a workshop hosted by the Department of Conservation, pp. 59–69. ISBN 0478224230.
  • Rowe, D. K. and Wilding, T. (2012). "Risk assessment model for the introduction of non‐native freshwater fish into New Zealand". Journal of Applied Ichthyology, 28 (4): 582–589.
  • McDowall, R. M. (2006). Crying wolf, crying foul, or crying shame: alien salmonids and a biodiversity crisis in the southern cool-temperate galaxioid fishes?. Reviews in Fish Biology and Fisheries, 16(3-4), 233-422.
  • Invasive species in New Zealand
  • List of introduced species

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  141. ^ Goodman, J.M.; Dunn, N.R.; Ravenscroft, P.J.; Allibone, R.M.; Boubee, J.A.T.; David, B.O.; Griffiths, M.; Ling, N.; Hitchmough, R.A; Rolfe, J.R. (2014). "Conservation status of New Zealand freshwater fish, 2013" (PDF). New Zealand Threat Classification Series 7. ISBN 9780478150148. 
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External links[edit]

Robert (Bob) McDowall[edit]

New Zealand dairy farming[edit]

Focus[edit]

Planetary boundaries
The Great Acceleration
Animal consciousness
Swarm intelligence

Fish intelligence[edit]

Fish hold the records for the relative brain weights of vertebrates. Most vertebrate species have brains that weigh about the same in proportion to their total body mass. The deep sea bathopelagic cusk-eel Acanthonus armatus,[1] is an ambush predator with a huge head. This fish has the smallest relative brain of all known vertebrates.[2] At the other extreme, the elephantnose fish, an African freshwater fish, has the largest relative brain of all known vertebrates.[3]

from goldfish

Goldfish can be trained to recognize and to react to light signals of different colors by using positive reinforcement.[4] Goldfish have a memory-span of at least three months and can distinguish between different shapes, colours and sounds.[5] Another experiment demonstrated retention of more than 1 month.[6] Fish respond to certain colors most evidently in relation to feeding.[7] Fish learn to anticipate feedings provided they occur at around the same time everyday. Goldfish can learn tricks, such as the limbo, slalom, fetch and soccer, using positive reinforcement training techniques.[8]


intelligence

From [16]:

A recent issue of Fish and Fisheries, devoted to learning, cited more than 500 research papers on fish intelligence, proving that fish are smart, that they can use tools, and that they have impressive long-term memories and sophisticated social structures. The introductory chapter said that fish are "steeped in social intelligence, pursuing Machiavellian strategies of manipulation, punishment and reconciliation … exhibiting stable cultural traditions and cooperating to inspect predators and catch food."

• Culum Brown, a University of Edinburgh biologist who is studying the evolution of cognition in fish, says, "Fish are more intelligent than they appear. In many areas, such as memory, their cognitive powers match or exceed those of 'higher' vertebrates, including non-human primates." Their long-term memories help fish keep track of complex social relationships. Their spatial memory—"equal in all respects to any other vertebrate"—allows them to create cognitive maps that guide them through their watery homes, using cues such as polarized light, sounds, smells, and visual landmarks.

• Dr. Phil Gee, a psychologist from the University of Plymouth, says that fish can tell what time of day it is, and he trained fish to collect food by pressing a lever at specific times. He says "fish have a memory span of at least three months," and they "are probably able to adapt to changes in their circumstances, like any other small animals and birds."

• "We're now finding that [fish] are very capable of learning and remembering, and possess a range of cognitive skills that would surprise many people." —Dr. Theresa Burt de Perera, Oxford University

• A scientific review presented to the Australian Veterinary Association completely disproved the old myth that goldfish have three-second memories; instead, the veterinarians found that goldfish have impressive memories and problem-solving abilities. One of the researchers said that after conducting the review, they wanted “to get the message out to vets to start looking more closely at fish and considering their welfare like they do other animals.” —The Sunday Times, May 28, 2006

• "Australian crimson spotted rainbowfish, which learnt to escape from a net in their tank, remembered how they did it 11 months later. This is equivalent to a human recalling a lesson learnt 40 years ago." —Sunday Telegraph, Oct. 3, 2004

memory


collective intelligence
swarm intelligence
The playful curiosity of this eagle ray reminded me of a story from the inventor of the " Deepflight “flying submarine.” On an early test dive, he found himself dancing with a curious eagle ray.... Moving like they do might be a signal of kinship... and may help express universal gestures for play... "Warm-blooded animals play; fish and reptiles do not... We are designed to play. We need 3D motion. The smarter the creature the more they play. The sea squirt auto-digests its brain when it becomes sessile." – Stuart Brown, founder of the Institute for Play
  • Victoria A. Braithwaite, Felicity Huntingford, Ruud den Bos. 2011. Variation in Emotion and Cognition Among Fishes. Journal of Agricultural and Environmental Ethics
  • Miklósi Á (2002) ["On the usefulness and limits of functional analogies"] Springer,

"Machiavellian Intelligence hypothesis" fish

video

References[edit]

  1. ^ Froese, Rainer and Pauly, Daniel, eds. (2009). "Acanthonus armatus" in FishBase. August 2009 version.
  2. ^ Fine ML, Horn MH and Cox B (1987) "Acanthonus armatus, a Deep-Sea Teleost Fish with a Minute Brain and Large Ears" Proceedings of the Royal Society B, 230(1259)257-265.
  3. ^ Nilsson G (1996) "Brain and body oxygen requirements of Gnathonemus petersii, a fish with an exceptionally large brain" Journal of Experimental Biology, 199(3): 603-607. Download
  4. ^ "Poissons rouges: la mémoire dans l'eau". Revue du Palais de la découverte. 217. April 1994. In a 1994 public experiment at the Palais de la Découverte science museum.
  5. ^ More recent research by the School of Psychology at the University of Plymouth in 2003. They were trained to push a lever to earn a food reward; when the lever was fixed to work only for an hour a day, the fish soon learned to activate it at the correct time.
  6. ^ The Discovery Channel's show Mythbusters tested the contemporary legend that goldfish only had a memory span of 3 seconds and were able to prove that goldfish had a longer memory span than commonly believed. The experiment involved training the fish to navigate a maze. It was evident that they were able to remember the correct path of the maze after more than a month.Mythbuster Results: A goldfish’s memory lasts only three seconds
  7. ^ According to a study at the start of the 2000s
  8. ^ Send Your Fish to School. ABC News: Good Morning America. Posted: May 7, 2008.