|Greater Amberjack (S. dumerili)|
G. Cuvier, 1816
A. Risso, 1810
Seriola is a genus of bony fish, commonly known as amberjacks. Nine extant species are currently recognized, although these were formerly split into many more. Also, several species are currently placed in several other genera of Carangidae that were originally described under Seriola. They are a large, carnivorous finfish popularly known for the firm texture and rich flavour of their flesh, which make them an ideal fish for aquaculture. Because specimens caught can weigh up to 41 kg (90 lb), and are powerful swimmers and hunters, they are also highly prized by sport fisherman.
Most Seriola species are either benthic, demersal or pelagic, and can be found down to 200 m in depth. All 9 species cover most of the globe in terms of distribution, usually in coastal waters. Most are shown to be pelagic spawners, releasing eggs into the open ocean habitat until hatching, and they do this through dioecious, external reproduction. Most Seriola species are found in schools, and have diets consisting of fish, squid and other invertebrates.
More than 150,000 tonnes of Seriola are produced through aquaculture per year. The majority is produced in Japan and Korea (Seriola quinqueradiata, Seriola dumerili and Seriola lalandi), with smaller contributions from New Zealand/Australia (Seriola lalandi) and America (Seriola rivoliana). Japanese yellowtail (Seriola quinqueradiata) accounts for more that 80% of global annual production. These cultured species are increasingly used in raw sushi, where they are known as hamachi, buri, kampachi and hiramasa.
Several trials are underway for land-based Seriola culture, but currently most Seriola fish are produced in cages, either in nearshore pens or in high-technology, submersible cages out in the open ocean. They are fed a range of diets, from trash fish to basic compound feeds to complex, formulated, compound feeds.
- Capture of wild stocks for culture (juveniles/broodstock for hatcheries) can have direct impacts on associated populations and ecosystems.
- There are environmental concerns over certain feeds used (fishmeal, oils, trash fish, etc.) for cultured carnivorous or piscivorous species.
- Disease is always of great concern within cultured species in terms of introduction and/or amplification of pathogens and parasites and subsequent infection of wild fish, as well as between farms.
- Escape of cultured fish is also a concern, which can have effects on wild stocks in terms of competition, predation and genetic alterations, depending on vulnerability and robustness.
- There is always a risk of pollution and habitat effects via nutrient losses and chemical additives, which can cause problems depending on habitat vulnerability and where the farms are in relation to the coast.
With effective management of regulations and good farming practices, these problems can be avoided. To address these impacts, the WWF is creating the Seriola and Cobia Aquaculture Dialogue (SCAD). The purpose of the SCAD is to create standards that will minimize the key impacts of Seriola/Cobia aquaculture and move producers towards better performance. This will be done by identifying the key environmental and social impacts associated with the farming of three types of Seriola (S. rivoliana, S. quinqueradiata and S. lalandi) and cobia, and principles established for addressing each impact. Then criteria will be developed to provide direction on how to reduce each impact. It is open to all stakeholders, including producers and other members of the supply chain, researchers, NGOs, government officials and investors. The standards (to be finalised late 2011) will be adopted by the Aquaculture Stewardship Council, which will then work with independent, third-party entities to certify farms that are in compliance with the standards.
There are currently nine recognized species in this genus:
- Seriola carpenteri F. J. Mather, 1971 (Guinean amberjack)
- Seriola dumerili (A. Risso, 1810) (Greater amberjack)
- Seriola fasciata (Bloch, 1793) (Lesser amberjack)
- Seriola hippos Günther, 1876 (Samson fish)
- Seriola lalandi Valenciennes, 1833 (Yellowtail amberjack)
- Seriola peruana Steindachner, 1881 (Fortune jack)
- Seriola quinqueradiata Temminck & Schlegel, 1845 (Japanese amberjack)
- Seriola rivoliana Valenciennes, 1833 (Almaco jack, highfin jack)
- Seriola zonata (Mitchill, 1815) (Banded rudderfish)