Broadgilled hagfish

From Wikipedia, the free encyclopedia
  (Redirected from New Zealand hagfish)
Jump to navigation Jump to search

Broadgilled hagfish
Eptatretus cirrhatus Iconographia Zoologica.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Myxini
Order: Myxiniformes
Family: Myxinidae
Genus: Eptatretus
Species: E. cirrhatus
Binomial name
Eptatretus cirrhatus
Synonyms[2][3]
  • Petromyzon cirrhatus Forster 1801
  • Homea banksii Fleming 1822
  • Eptatretus banksii (Fleming 1822)
  • Heptatremus banksii (Fleming 1822)
  • Bdellostoma forsteri Müller 1836
  • Bdellostoma heptatrema Müller 1836
Drawing by Dr Tony Ayling
Illustration of the mouth

The broadgilled hagfish or New Zealand hagfish (Eptatretus cirrhatus) is a hagfish found around New Zealand and the Chatham Islands as well as around the south and east coasts of Australia, at depths between 1 and 900 metres.

Description[edit]

Eptatretus cirrhatus, more commonly known as the New Zealand hagfish or the Broadgilled hagfish has an eel-like body with no dorsal fin, a paddle-like tail and are often a grey-brown with a pink or bluish tinge of colour.[4] Hagfish are an ancient species that evolved around 300 million years ago and have changed little externally since then. Hagfish and lamprey are basal vertebrates. The hagfish eyes lack lenses and are covered skin making them not visible externally and are erroneously called blind eels (rhodopsin and melanopsin have been fourd in its retina: PUBMED 27189541). The New Zealand hagfish has a skull but no jaw or true vertebral column, it instead has a skeleton made up of cartilage.[5] The rounded mouth of the hagfish is surrounded by 6 barbels, above that is their singular nasal passage and just inside the mouth is a dental plate with a row of posterior and anterior keratinous grasping teeth on each side (Clark & Summers, 2007). It has seven pairs of gill pouches [6] and forming a line down both the lower sides of its body are pores which often many of the are ringed with a white colour and are used for secreting a snot-like slime which expands out once it has contact with the sea water.[7] Juveniles are lighter in colour.

Distribution[edit]

Natural global range[edit]

General hagfish are found around the world in waters below 22 degrees Celsius.[8] E. cirrhatus has a range that includes the western pacific [9] and stretches down the east coast of Australia from Queens land to Tasmania as well as throughout New Zealand from the North Cape to Snares Shelf and around the Chatham Islands.[10]

New Zealand range[edit]

E. cirrhatus is found in coastal areas of New Zealand in shelf and slope areas along the coast with frequent sighting in Kaikoura. It is also found on rises and banks out in the open ocean. Their New Zealand range includes the Chatham Islands.[11]

Habitat preferences[edit]

The New Zealand Hagfish is common throughout the temperate coastal shelves, in depths ranging between 1m and 900m. The hagfish is most common between 90 and 700m.[12] “All known Hagfish species live in close proximity to the bottom, either resting on the substrate or occupying burrows [13]

Life cycle/Phenology[edit]

In a study done on the reproductive stages, there was no indication found that Eptatretus cirrhatus breeds cyclically or seasonably as females with large eggs present and postovulatory females were found throughout all seasons of the study. It was suggested that the first female spawning is thought to occur when the total length is between 412mm – 534mm, while Males are thought not to mature until they are about 585mm in length. Not much is yet understood about the gestation period of the Eptatretus cirrhatus but they did find a low reproductive rate occurring and therefore issues may arise from commercial fisheries,[14] although they are currently at a ‘least concern’ IUCN It can take up to 2 or 3 years after maturing for hagfish to produce only 20–30 eggs. Embryo development is slow with early stages developing at only 7 months in some species of hagfish.[15] “The ovary is found in the anterior portion of the gonad, and the testis is found in the posterior part.[16][17] indicates four outcomes can happen during development that determines the sex of an individual. If the anterior part develops then the individual is female if the posterior part develops the individual is male. If neither develops the individual becomes sterile. If the individual develops both then the individual becomes a hermaphrodite, research is currently being undertaken to determine where hermaphrodites are to be considered functioning or not.

Diet and foraging[edit]

E. cirrhatus are bottom feeders and are known to eat their prey from the inside out.[18] Their diet mainly consists of carrion, although they prey on live animals as well. Hagfish play an important role in the ecosystem, recycling nutrients contained in carcasses that sink to the sea floor.[19] As the hagfish are practically blind except for their sensitivity to light they rely on the 6 sensory barbels that surround their mouths to find their way along the ocean floor and their singular nasal passageway to smell out their prey.[20] Hagfish have a unique dental plate inside of their mouths with a row of posterior and anterior keratinous grasping teeth on each side. This dental plate folds bilaterally helping with the grasping motion hagfish use to eat their prey. The dental plate protrudes out and folds onto the flesh of the prey and then retracts back into the hagfish's mouth.[21] It may also use its slime to suffocate its prey though this is mostly used as a defense against predators.[22] The moment a predator grasps a hagfish it will project slime out of its pores, causing the predator to choke. The slime clogs the gills and therefore restricts the rate at which the predator can circulate water to breathe.[23]

For many years, it was believed that E. cirrhatus was a scavenger and opportunistic feeder. However, it was realised that the energy demands of the population were too large to be maintained by scavenging alone.[24] Research done in the last decade has shown that hagfish can and do hunt. E. cirrhatus feeds on the third trophic level (three levels above primary producers).[25] The diet is a variety of invertebrates and includes hermit crabs, shrimps, sharks and bony fish. When hunting the hagfish locates a burrow occupied by potential prey. It then enters the burrow and is believed to grab the prey. It is then thought that hagfish may suffocate its prey by producing an excess of slime. To extract the prey from the burrow E. cirrhatus ties itself into a knot which in turn increases the surface area of contact with the ocean floor and acts as leverage for pulling the prey out.

Predators, Parasites, and Diseases[edit]

E. cirrhatus secretes a slime that acts as a deter to predators. Hagfish are hunted by marine mammals and sharks as well as large fish. However, hagfish combat this predation with the slime that they secrete. When grabbed by a predator, the slime fills the mouth and gill chamber. These trigger a gagging response in the predator, thus forcing them to let go of the hagfish. This deters further attack as well, though it is unknown whether there is a toxic compound within the slime and what further effect this has on the predator.[26] Marine mammals and octopuses do not have gills that can be clogged by slime. This slime is made in pores along the sides of hagfish and contains protein threads. These are coiled when contained in cells, but upon release reacts with salt water and expands. This is what causes the slime to fill the mouth.[27] The excretion of the slime appears to have no effect on E. cirrhatus, as it continues foraging despite attacks. This is considered unusual behaviour as in most animals they would be more alert for potential danger or in timid species, run or hide at the threat of danger. Hagfish just keep eating with no change in behaviour again providing an adaptive advantage as instead of using energy on flight, the organism can gain energy from its food. It is possible that the slime that is secreted by hagfish could, like in more evolved species, as protection against pathogens and parasites [28]

Cultural uses[edit]

Commercially Hagfish are considered a delicacy in Korea and Japan. This has led to a small-scale fishing in New Zealand which helps to supply this industry. The skin is used to produce eel skin leather.[29] This industry has no regulations unlike many others because of a large number of unknown factors about Hagfish life cycles. It is difficult to regulate when the size of the population is unknown as well as the growth and fertility rate.[30] This makes the industries sustainability questionable and has led to a lot of research into hagfish reproduction. But due to the depth at which this species inhabits and the difficulty in observing their behaviour limited knowledge has been gained.

Other uses[edit]

Hagfish slime is really quite incredible and biometrics research work has been done on understanding the protein fibres within the hagfish slime to find potential uses for it. In an interview with Douglas Fudge of the University of Guelph in Ontario, Canada who heads the research team looking into the hagfish slime states that when dried out the fibres within the slime become very silk-like, the fibres being very thin and strong. “Hagfish slime is made up of two parts: mucus and tiny fibres, about 15cm long but only a micron wide (National Geographic, 2014).” It could be a natural renewable alternative to non-renewable fabrics like nylon and spandex which are made from oil. They propose that in the future (even though no one has been able to extract the proteins and make a spool of hagfish thread yet), that the proteins will be able to be extracted and made into eco-friendly clothing such as athletic wear or even because of the strength bulletproof vests.[31]

References[edit]

  1. ^ Mincarone, M.M. (2011). "Eptatretus cirrhatus". The IUCN Red List of Threatened Species. IUCN. 2011: e.T154825A4644581. doi:10.2305/IUCN.UK.2011-1.RLTS.T154825A4644581.en. Retrieved 24 December 2017.
  2. ^ Froese, R.; Pauly, D. (2017). "Myxinidae". FishBase version (02/2017). Retrieved 18 May 2017.
  3. ^ "Myxinidae" (PDF). Deeplyfish- fishes of the world. Retrieved 18 May 2017.
  4. ^ (Ministry of Fisheries, 2011)
  5. ^ (Encyclopedia of Britannica, 2011)
  6. ^ (Zintzen et al., 2015)
  7. ^ (Bray, n.d.)
  8. ^ (Powell et al., 2005)
  9. ^ (Fishbase, 2017)
  10. ^ (Zintzen et al., 2015)
  11. ^ (Zintzen et al., 2015)
  12. ^ (Ministry for Primary Industries, 2014)
  13. ^ (Martini, & Beulig, 2013)
  14. ^ (Martini & Beulig, 2013)
  15. ^ (Ministry for Primary Industries, 2014)
  16. ^ (Reyes, n.d.)
  17. ^ Reyes (n.d.)
  18. ^ (Knight, 2014)
  19. ^ (IUCN, 2011)
  20. ^ (Holmes et al., 2011)
  21. ^ (Clark & Summers, 2007)
  22. ^ (Zintzen et al., 2011)
  23. ^ (Lim et al., 2006)
  24. ^ (Beulig & Martini, 2013)
  25. ^ (Zintzen et al.,2013)
  26. ^ (Zintzen et al., 2011)
  27. ^ (Winegard et al., 2014)
  28. ^ (Zintzen et al., 2011)
  29. ^ (Beulig & Martini, 2013)
  30. ^ (Powell et al., 2005)
  31. ^ (Rothschild, A., 2013)
  • "Eptatretus cirrhatus". Integrated Taxonomic Information System. Retrieved 18 April 2006.
  • Froese, Rainer and Pauly, Daniel, eds. (2006). "Eptatretus cirrhatus" in FishBase. January 2006 version.
  • Tony Ayling & Geoffrey Cox, Collins Guide to the Sea Fishes of New Zealand, (William Collins Publishers Ltd., Auckland, New Zealand 1982) ISBN 0-00-216987-8
  • Ministry of Fisheries, "New Zealand Fishes. A field guide to common species caught by bottom and midwater fishin",. (Ministry of Fisheries., 1(68), 34., 2011) ISSN 1176-9440
  • Encyclopedia of Britannica. (24 May 2011). Hagfish. Retrieved from https://www.britannica.com/animal/hagfish
  • Zintzen, V., Roberts, C. D., Shepherd, L., Stewart, A. L., Struthers, C. D., Anderson, M. J., McVeagh, M., Noren, M., & Fernholm, B. (2015) Review and phylogeny of the New Zealand hagfishes (Myxiniformes: Myxinidae), with a description of three new species. Zoological Journal of the Linnean Society. 174 (2), 363–393. doi:10.1111/zoj.12239
  • Bray, D. (n.d.) Eptatretus cirrhatus. Retrieved from http://fishesofaustralia.net.au/home/species/1999#summary
  • Powell, M.L., Kavanaugh, S.I. & Sower, S.A. (2005) Current Knowledge of Hagfish Reproduction: Implications for Fisheries Management. Integrative and Comparative Biology. 45(1), 158–165. doi:10.1093/icb/45.1.158
  • Ministry for Primary Industries. (2014). Proposed Introduction of the Common Hagfish (Eptatretus cirrhatus) into the Quota Management System on 1 October 2014. Retrieved 2017, from file:///C:/Users/Emma/Downloads/7789044-2014-21-Final-Advice-Proposed-Introduction-of-common-hagfish-into-the-QMS.pdf
  • Martini, F.H., & Beulig, A. (2013). Morphometics and Gonadal Development of the Hagfish Eptatretus cirrhatus in New Zealand. PLoS ONE. 8(11). doi:10.1371/journal.pone.0078740
  • Reyes, R. B. (n.d.). Eptatretus cirrhatus summary page. Retrieved 2017, from http://www.fishbase.org/summary/Eptatretus-cirrhatus.html
  • Knight, K., (2014). Adhesive constrains hagfish thread skeins. Journal of Experimental Biology. 217, 1199–1200. doi:10.1242/jeb.105841
  • IUCN. (2011, July). Depletion of body snatchers: bad news for marine environment. Retrieved from http://www.iucnredlist.org/news/hagfishpaper
  • Holmes, W. M., Cotton, R., Xuan, V. B., Rygg, A. D., Craven, B. A., Abel, R. L., Slack, R. & Cox, J. P.L. (2011), Three-Dimensional Structure of the Nasal Passageway of a Hagfish and its Implications for Olfaction. The anatomical Record, 294(6), 1045–1056. doi:10.1002/ar.21382
  • Clark, A. J. & Summers, A. P. (2007). Morphology and kinematics of feeding in hagfish: possible functional advantages of jaws. The Journal of Experimental Biology. (210), 3897–3909. doi:10.1242/jeb.006940
  • Lim, J., Fudge, D. S., Levy, N., & Gosline, J. M. (2006). Hagfish slime ecomechanics: testing the gill-clogging hypothesis. Journal of Experimental Biology. 209, 702–710. doi:10.1242/jeb.02067
  • Zintzen, V., Rogers, K.M., Roberts, C.D, Stewart, A.L. & Anderson, M.J. (2013) Hagfish feeding habits along a depth gradient inferred from stable isotopes. Mar Ecol Prog Ser 485:223–234. doi:10.3354/meps10341

(Lots of relevant information and references)

External links[edit]