American Oceans
up close image of an atlantic wolffish

Atlantic Wolffish

The Atlantic Wolffish – scientific name Anarhichas lupus – has many names, including devilfish, wolf eel, Atlantic catfish, seawolf, ocean catfish, sea cat, or woof.

It is one of many fish species that classify as the Anarhichadidae wolffish family. But its sharp, protruding teeth (even when the mouth is closed) make it an easily distinguishable species.

Characteristics & Appearance

atlantic wolffish

Atlantic Wolffish have a unique appearance and features that make it easily identifiable from other species of fish.

Weight & Length

The Atlantic wolffish can grow to six feet long and weigh up to 50 pounds (24 kg).

Physical Characteristics & Color

Atlantic wolffish has a long, subcylindrical body, with a compressed caudal. Rather than having rough scales, these fish are slippery and smooth. Their scales are embedded into their skin and difficult to see.

These fish can be various colors, ranging from dull olive green, purplish-brown, or blue-gray. The back’s whole length has an even dorsal fin, with a similar one extending from the caudal fin to the vent.

Wolffish do not have pelvic fins, but they do have large, rounded pectorals. Much of their body resembles an eel, which does cause them to swim slowly by moving their bodies side to side.

The most notable feature of an Atlantic wolffish is the large teeth, which makes this species easily identifiable from other wolffish relatives. Their unique tooth structure consists of multiple rows of specifically shaped teeth.

  • Front row: four to six fanged conical teeth on upper and lower jaws.
  • Upper jaw: three rows of crushing teeth; third row has four molar pairs; blunted conical teeth on the outer set.
  • Lower jaw: two sets of molars behind the front conical fangs

In addition to their deadly teeth, these fish also have serrated teeth throughout their throats. All of these teeth allow them to consume foods with hard shells.

Lifespan & Reproduction

Atlantic wolffish live up to twenty years old and have a late maturity cycle, being incapable of sexually reproducing until they are eight to ten years old.

These wolffish form breeding pairs in spring to summer and mate in the fall. Their method of fertilizing their eggs is much different from most fish species.

Females do not deposit eggs in the open ocean for the male to fertilize. Rather, the eggs are fertilized inside the female fish. One female can produce anywhere from 5,000 to 12,000 eggs in her lifetime. The size of the fish affects the number of eggs, with larger females laying more.

up close image of an atlantic wolffish

Once the female lays her eggs on the ocean floor, the male wolffish stays around to help protect them, sometimes up to four months. Wolffish eggs are the largest of any fish, with sizes of 5.5 to 6mm diameters. They have an opaque, yellowish tint and clump together.

It can take between three to nine months for the fish eggs to hatch, based on water temperature. They stay at the bottom of the ocean during the larvae stage, close to the hatch site.

It can take a few hours to one week before the larvae are ready to venture into the water column, where they’re pelagic for two weeks to two months. They become benthos once they’re ready to find a home.

Habitat

Atlantic Wolffish are a saltwater fish so they live only in the ocean. You won’t find these fish in lakes, ponds, streams, or rivers.

Where Do Atlantic Wolffish Live?

Atlantic wolffish live along the east and west coast of the northern Atlantic Ocean. They venture as far north in the western Atlantic as the Davis Strait, Nunavut territory in Canada.

Some species are seen in Nova Scotia, Greenland, and Newfoundland. They travel south as far as Cape Cod. Rare sightings have occurred in New Jersey. The largest populations occur in the Great South Channel, Georges Bank, and the Gulf of Maine.

Along the eastern Atlantic coastline, these fish extend from the Bay of Biscay, up through the British Isles and Nordic countries, and into the White Sea in Russia to Novaya Zemlya in the Arctic Ocean. You can also find them in Asian waters.

Anarhichas lupus in the ocean

Atlantic wolffish are stationary, preferring to stay near their home, and as benthic dwellers, they live along the hard, rocky ocean floor. They commonly nest in small caves or nooks.

They live at depths of 66 to 1,640 feet in cold water as low as 30°F to 52°F (-1 to 11°C). Their bodies’ makeup allows them to survive near-freezing temperatures.

Food & Diet

The Atlantic Wolffish has a unique diet of hard foods found in the ocean. They rarely eat other fish species.

What Do Atlantic Wolffish Eat?

The strong jaws and teeth structure of the Atlantic Wolffish allows them to have a diet of hardshell crustaceans, mollusks, and echinoderms. However, despite their fierce appearance, these fish do not eat other fish species.

They also enjoy meals of large hermit crabs, sea clams, cockles, large whelks, sea urchins, and green crabs, and starfish. Atlantic wolffish play a crucial role in population control of urchins and green crabs, which populate quickly and pose risks to the ecosystem’s health.

Threats & Predators

Understanding the common threats and predators of the Atlantic Wolffish is an important part of proper conservation of the species.

Human Threats

Although you cannot legally fish for Atlantic Wolffish, they are commonly caught unintentionally by commercial fishermen using nets. In 1983, over 1,200 metric tons of wolfish were accidentally captured by fishermen. By 2009, this percentage had lowered 97% to 31.6 tons.

fish in net caught as bycatch

However, another human threat besides commercial fishing is otter trawling. This process drags large nets along the ocean floor, which can cause significant damage to the wolffish’s rocky habitat and catch them in the nets during the process.

Climate Change & Global Warming

The effects of climate change and global warming can pose risks to the Atlantic wolffish. Since these fish live in cold water, the oceans’ increasing temperatures can negatively impact and limit the habitats for these wolffish. As a response, scientists see more wolffish migrate to deeper waters.

Another issue plaguing this fish species is ocean acidification. Although it may not directly harm the fish, it does affect their molluscan prey, limiting their food source.

Predators

Wolffish do not have many natural predators in their environments. The only significant predator that would feed off this species is Atlantic cod.

The wolffish larvae are at risk of being prey to Atlantic cod, Greenland sharks, gray seals, haddock, and some spotted wolffish. There are even instances where the wolffish larvae eat each other.

Other Threats

The Atlantic wolffish’s slow sexual maturity rate does put this species at risk. Due to overfishing, once the population drops, it can take a long time to restock since it can take almost a decade for this species to be ready to reproduce.

Conservation Status

The Atlantic Wolffish species has rapidly declined, which resulted in being listed as a Species of Concern by the U.S. Marine Fisheries Service in 2004.

Despite the declining population, the National Marine Fisheries Service (NMFS) has not yet moved this species to an Endangered status, which would legally protect them under the Endangered Species Act.

Fun Facts About Atlantic Wolffish

  • Atlantic wolffish produce natural antifreeze that keeps their blood moving in cold waters. This unique feature allows them to survive in nearly freezing waters.
  • Since wolffish feed on hard foods, a lot of trauma occurs to their teeth. Each year after spawning, these fish lose all of their teeth and grow new ones. For a fish that lives to be twenty and sexually matures at the age of ten, that’s ten new sets of teeth in one lifecycle.
  • The internal fertilization of the wolffish is significantly different from the broadcast spawning of most other fish species. And they’re one of a few who have the male and female attend to the eggs and young after birth.
  • Another interesting fact is that female wolffish hold their eggs inside from four to nine months (the same length of time as a human baby). Water temperatures affect the exact length.
  • Once the male wolffish starts to protect the eggs, he will stop feeding and becomes extremely aggressive towards anything that comes into their territory.
  • Although the Atlantic wolffish is a sedentary fish that spends most of its time near home, it will migrate to colder waters during spawning seasons. And they may travel short distances from their home to hunt for food.

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