Wolf eel

The wolf eel (Anarrhichthys ocellatus) is a species of marine ray-finned fish belonging to the family Anarhichadidae, the wolf fishes. It is found in the North Pacific Ocean.[2] Despite its common name and resemblance, it is not a true eel. It is the only species in the monotypic genus Anarrhichthys.

For the green wolf eel of the Indo-Pacific, see Congrogadus subducens.

Wolf eel
Wolf eel in Puget Sound
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Scorpaeniformes
Family: Anarhichadidae
Genus: Anarrhichthys
Ayres, 1855
Species:
A. ocellatus
Binomial name
Anarrhichthys ocellatus
Ayres, 1855
Synonyms[2]
  • Anarhichas ocellatus (Ayres, 1855)
  • Anarrhichas felis Girard, 1854
  • Anarrhichthys felis Girard, 1858

Taxonomy

The wolf eel was first formally described in 1855 by the American physician and ichthyologist William Orville Ayres with the type locality given as San Francisco Bay in California.[3] It is the only species in the monotypic genus Anarrichthys, which was also described by Ayres in 1855.[4] This is one of two genera in the family Anarhichadidae, the other being Anarhichas.[5]

Etymology

The Wolf eel’s genus name Anarrhichthys combines the wolffish genus Anarhichas, as this taxon has a similar head shape to the wolffishes, and ichthys, which means “fish”. The specific name ocellatus means “ocellated”, a reference to the eye like spots, or ocelli, on the dorsal fin and body.[6]

Wolf eel at the Dallas Children's Aquarium

Description

A. ocellatus differs from true eels, as they have paired gill slits and pectoral fins. The animal can grow up to 2.4 m (7 ft 10 in) in length and 18.4 kg (41 lb) in weight.[2]

Younger wolf eels are orange with big dark spots in the posterior part of the body. Once older they turn grey, brown greyish or dark olive.[7][8]

They possess powerful jaws with which they crush their prey: canine teeth in the front and molars in the posterior portion of the mouth. In the anal fin, it has no rays and 233 radials. It only has one dorsal fin, that extends from the head to the end of the body, with 228 to 250 flexible fishbones without soft radius. The caudal fin is small. It has no pelvic fins, nor a lateral line.[9]

Males have large lips and a protuberance on the superior part of the head. The lifespan of this species is about 20 years.[10]

Reproduction

Wolf eels have a monogamous relationship and tend to mate for life and live in the same cave. They reproduce from October until the end of winter, beginning when they are around seven years old. The male places his head against the female's abdomen and wraps around her, while she extrudes the eggs, up to 10,000 at a time, which he then fertilizes. She coils around the eggs, using her body to shape the eggs into a neat sphere, roughly the size of a grapefruit. The male then coils around her. Together they protect the eggs, and only one leaves the cave at a time, to feed.[2] The eggs hatch after 91 to 112 days, and during this period, in order to ensure their oxygenation, the female circulates water around the eggs and periodically massages and rotates the eggs as they develop.[7][11][12]

Ecology

Distribution

A. ocellatus is found in caves, crevices and rocky reefs from shallow waters to a depth of 226 m (741 ft), ranging from the Sea of Japan and the Bering Sea to Northern California.[2]

Behavior
A small juvenile wolf eel
A pair of wolf eel with eggs (pale yellowish)

Large wolf eels are curious[13] and are rarely aggressive, but are capable of inflicting painful bites on humans.[2] The male and female may pair for life and inhabit a cave together; the two watch their eggs together and one always stays behind when the other leaves to feed.[2][8]

Diet

This eel-like fish feeds on invertebrates with hard shells (crustaceans, sea urchins, mussels, clams) and some fishes, crushing them with its strong jaws.[11][12] It has been observed in captivity that when they are fed soft food such as squid, they tend to prefer it over hard food, which can damage the back teeth.[7]

Predators

The adult's predators are sharks, big fish and harbor seals.[14][15] The eggs and juveniles can be threatened by more species. The juveniles are vulnerable as they are not very large and do not have powerful jaws. Fish such as rockfish and kelp greenling will prey on the juveniles.[7]

As food

The wolf eel has edible, sweet and savory white flesh. In some coastal northwest Native American tribes, the wolf eel was referred to as the sacred "doctorfish". Only the tribal healers were allowed to eat this fish, as it was supposed to enhance their healing powers.[8]

References
  1. Orr, W. & Workman, G. (2021). "Anarrhichthys ocellatus". IUCN Red List of Threatened Species. 2021: e.T159099689A159100591. doi:10.2305/IUCN.UK.2021-1.RLTS.T159099689A159100591.en. Retrieved 27 July 2022.
  2. Froese, Rainer; Pauly, Daniel (eds.) (2022). "Anarrhichthys ocellatus" in FishBase. February 2022 version.
  3. Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Anarrichthys". Catalog of Fishes. California Academy of Sciences. Retrieved 27 July 2022.
  4. Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Genera in the family Anarhichadidae". Catalog of Fishes. California Academy of Sciences. Retrieved 27 July 2022.
  5. Froese, Rainer, and Daniel Pauly, eds. (2016). "Anarhichadidae" in FishBase. November 2016 version.
  6. Christopher Scharpf & Kenneth J. Lazara, eds. (4 July 2021). "Order Perciformes: Suborder Cottoidea: Infraorder Zoarcales: Families: Anarhichadidae, Neozoarcidae, Eulophias, Stichaeidae, Lumpenidae, Ophistocentridae, Pholidae, Ptilichthyidae, Zaproridae, Cryptacanthodidae, Cebidichthyidae, Scytalinidae and Bathymasteridae". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Retrieved 27 July 2022.
  7. "Wolf-eel, Reefs & Pilings, Fishes, Anarrhichthys ocellatus at the Monterey Bay Aquarium". Montereybayaquarium.org. Retrieved 2019-11-26.
  8. Sempier, S. (2003). "Wolf Eel". Archived from the original on July 20, 2011. Retrieved July 13, 2009. Marine Species with Aquaculture Potential.
  9. "Wolf-eel • Anarrhichthys ocellatus". Centralcoastbiodiversity.org. Retrieved 21 July 2022.
  10. Beamish, RJ; McFarlane, GA; Benson, A (2006). "Longevity overfishing". Progress in Oceanography. 68 (2–4): 289–302. Bibcode:2006PrOce..68..289B. doi:10.1016/j.pocean.2006.02.005. Retrieved 2022-07-16.
  11. Coleman, R. M. (1999). Parental care in intertidal fishes. USA: Academic Press. pp. 165–180. ISBN 9780123560407.
  12. Love, M. (1996). Probably More Than You Want to Know About the Fishes of the Pacific Coast. California, USA: Really big press. ISBN 0962872555.
  13. "Archived copy". Archived from the original on 2010-12-16. Retrieved 2011-01-28.{{cite web}}: CS1 maint: archived copy as title (link)
  14. "National Aquarium | Wolf Eel". National Aquarium. Retrieved 2019-11-26.
  15. "Wolf-eel". Alaska Sealife Center. Retrieved 2019-11-27.
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