Wolf-eels are found in the temperate North Pacific in coastal waters from the Sea of Okhotsk and the Sea of Japan to the Aleutian islands and along the western coast of North America to Baja California. (Feeney, et al., 2007; Froese, 2008)
Wolf-eels are exclusively marine, found in shallow, cold, coastal waters. They have been found in depths as low as 226 meters, but are generally found in shallow water. They are demersal in their habits, being found almost exclusively in sheltered, rocky, sub-tidal areas or near rocky structures in areas with sandy bottoms. They remain in a rock shelter unless excluded by a larger wolf-eel or octopus. Juvenile stages are pelagic for their first 2 years of life. (Froese, 2008; Sempier, 2003)
Wolf-eels are large, eel-like fish similar in appearance to morays (Muraenidae). They are up to 240 cm in total length and a maximum of 18.4 kg. They have robust heads and large pectoral fins with 18 to 24 rays. The body is long and tubular, tapering to a pointed tail. Wolf-eels have the most elongated morphology of other wolf-fishes (Anarhichadidae), which are mostly only moderately elongate. They have a single, long dorsal fin that stretches the length of their body, tapering to a point at the tail. It has 218 to 250 flexible spines. The anal fin is also long, with 180 to 233 soft rays. There are no pelvic fins. Wolf-eels have a single pair of nostrils, a moderately well-developed lateral line, and no swim bladder. These fish have very robust, caniniform teeth. (Froese, 2008)
Wolf-eel eggs are protected by both parents until they hatch at 91 to 112 days. Juveniles are pelagic, drifting in water currents until they reach 2 years old, at which point they settle in shallow, coastal areas with structures that provide denning sites. (Froese, 2008; Sempier, 2003)
Males and females form monogamous pairs at about 4 years old, or 91.4 cm in length. Some evidence suggests they mate for life. (Sempier, 2003)
Estimates of age at sexual maturity vary in the literature, some sources suggest that males and females for mated pairs at about 4 years old, or 91.4 cm in length, other sources suggest female maturity is reached at 7 years old. Females can lay up to 10,000 eggs at a time. Eggs take 91 to 112 days to hatch. Fertilization is external, but few details about mating behavior or periodicity are reported. (Sempier, 2003)
Both males and females will wrap their bodies around their egg masses to protect them until hatching. They aggressively defend egg masses in their rocky dens until they hatch. (Froese, 2008)
Wolf-eels remain in their rock crevices during the day and emerge to forage at night. They roam widely looking for fish and invertebrate prey, but have a great deal of site fidelity - returning to the daytime dens and inhabiting them for long periods of time. Vacated dens are rapidly inhabited by other wolf-eels, though, so they may patrol potential den sites regularly. They seem to be territorial, aggressively defending their den area. Wolf-eels are occasionally caught by hook and line anglers, so there may be some limited daytime activity. (Hulberg and Graber, 1980)
Home range sizes are not reported for wolf-eels
There is little information available on communication and perception in wolf-eels. It is likely that the most important modes of perception are vision and use of the lateral line to detect motion and vibrations. (Froese, 2008; Sempier, 2003)
Wolf-eels use their robust jaws and teeth to eat hard-shelled invertebrates, such as crabs up to 114 mm in width, snails, sand dollars, sea urchins, mussels, clams, and abalone, especially Haliotis kamtschatkana. In the Monterey area the dominant food items are slender crabs (Cancer gracilis) and sand dollars (Dendraster excentricus). Wolf-eels occasionally eat fish as well, although they seem best able to capture slow-moving prey. (Emmet and Jamieson, 1988; Froese, 2008; Hulberg and Graber, 1980; Sempier, 2003; Waldron, 1958)
Wolf-eel eggs are eaten by rockfish (Sebastes species) and kelp greenlings (Hexagrammos decagrammus). Wolf-eels aggressively defend their territories. When threatened, they approach the threat with the mouth held open, displaying the teeth. (Sempier, 2003)
Wolf-eels are considered good to eat and are taken for food by humans. There are small-scale commercial fisheries that take wolf-eels and they are considered a potential species useful in aquaculture. Wolf-eels are kept in zoos and aquariums, although they are difficult to keep and may be aggressive. (Froese, 2008; Sempier, 2003)
Wolf-eels have not been evaluated by the IUCN red list. Several of their close relatives, species of wolfish (Anarichas), are considered threatened or species of concern by the Canadian Species at Risk program, prompting recent genetic research on this group. In coastal California, reports suggest wolf-eel populations are large, but no systematic survey is reported. (Hulberg and Graber, 1980; Johnstone, et al., 2007)
The generic name comes from the Greek anarrhichesis, meaning to climb. (Froese, 2008)
Tanya Dewey (author), Animal Diversity Web.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
fertilization takes place outside the female's body
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
eats mollusks, members of Phylum Mollusca
Having one mate at a time.
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
an animal that mainly eats fish
mainly lives in oceans, seas, or other bodies of salt water.
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
Beamish, R., K. Leask, O. Ivanov, A. Balanov, A. Orlov, B. Sinclair. 1999. The ecology, distribution, and abundance of midwater fishes of the Subarctic Pacific gyres. Progress in Oceanography, 43: 399-422.
Emmet, B., D. Jamieson. 1988. An experimental abalone transplant project in Barkley Sound, British Columbia. Fisheries Bulletin, 87: 95-104.
Feeney, R., R. Lea, S. Dyer, S. Gietler. 2007. First Record of the Wolf-Eel, Anarrhichthys ocellatus (Pisces: Anarhichadidae), from Baja California, Mexico. California Fish and Game Scientific Journal, 93: 52-55.
Froese, R. 2008. "Anarrhichthys ocellatus (wolf-eel)" (On-line). fishbase.org. Accessed January 28, 2009 at http://www.fishbase.org/summary/speciessummary.php?id=3813.
Hulberg, L., P. Graber. 1980. Diet and behavioural aspects of the wolf-eel Anarrhichthys ocellatus, on sandy bottom in Monterey. California Fish and Game Scientific Journal, 66: 172-177.
Johnstone, K., H. Marshall, S. Carr. 2007. Biodiversity genomics for species at risk: patterns of DNA sequence variation within and among complete mitochondrial genomes of three species of wolffish (Anarhichas spp.). Canadian Journal of Zoology, 85: 151-158.
Sempier, S. 2003. "Wolf Eel" (On-line). Marine Species with Aquaculture Potential, Oregon State University. Accessed January 29, 2008 at http://hmsc.oregonstate.edu/projects/msap/PS/masterlist/fish/wolfeel.html.
Waldron, K. 1958. The fishery and biology of the Dungeness crab (Cancer magister Dana) in Oregon waters. Contributions of the Oregon Fish Commission, 24: 1-20.