Atlantic Wolffish: Characteristics, habitat, related species and more….

The Atlantic Wolffish is one of the many fish  that take their name from other animals that keep a certain resemblance with them or share common characteristics. Let’s know everything about this species today.

This species is also known as seawolf, Atlantic catfish, ocean catfish, devil fish and  wolfeel.  Its scientific name is Anarhichas lupus  and it’s a species belonging to the Anarhichadidae family.


Kingdom: Animals Phylum: Chordata Class: Actinopterygii (ray-finned fishes) Order: Perciforms Family: Anarhichadidae Genus: Anarhichas Species: A. lupus


The Anarhichadidae are a family of marine fish included in the order Perciformes. They are distributed throughout the North Atlantic and Arctic Ocean.

Their bodies are extremely elongated and their dorsal fin, (with soft rays), runs almost the entire Atlantic Woffish : Different Wolffish Speciesback, but is separated from the caudal fin.

Most species have strong canine and molar teeth, specialized in crushing the shells of mollusks and shellfish shells from which they  feed.

Because of their sedentary habits, they have openings between the gills that are very separate and have no swim bladder.

The Atlantic Wolffish’ Main Characteristics

The Atlantic wolfish has a unique and special appearance since it has teeth that resemble a wolf’ jaw. Both the lower and upper jaws are armed with four to six fang-like, strong, conical teeth. Behind the conical teeth in the upper jaw, there are three rows of crushing teeth.

The central row has four pairs of molars and the outer rows house blunted conical teeth. In addition, the lower jaw has two rows of molars behind the primary conical teeth. The wolffish’s throat is also scattered with serrated teeth.

As for its body, it has an elongated and sub cylindrical shape in the front, with a smooth and slippery texture.

Its scales are rudimentary and are embedded and hide almost all of its skin.

The largest recorded specimen measured 1.5 meters long with almost 18 kilograms in weight.

Its body color ranges between purple and brown, opaque olive green and a bluish gray.

Anarhichas lupus has a uniform dorsal fin that extends throughout the back and a fin that starts from its breathing area to the caudal fin.  In addition, It has large rounded pecs and no pelvic fins. Its body is similar to that of an eel and, therefore, it swims very slowly.

Other interesting facts about Atlantic Wolffish

Fish belonging to this family have always been in charge of controlling the populations of green crabs and sea urchin. This makes the value of this species high, since it helps us control certain species that are more harmful to the habitat if left unattended. In addition, the Atlantic wolfish is an indicator of the good state of the seabed, since if it were contaminated, it could not survive.

In addition to their unique appearance, wolves are distinguished by the natural antifreeze they produce to keep their blood flowing fluidly in their very cold habitat, the participation of both male and female in breeding, and the large size of their eggs.

Let’s watch them

Where do Atlantic Wolffish Inhabit?

This fish can be found on the west and east coasts of the Atlantic Ocean. It can also be found in the Davis Strait, near the Canadian area of ​​Nunavut.

Since Atlantic wolfish aren’t skilled swimmers, they tend to be stationary fish. They usually stay near their houses built on the rocks in the benthic zone of the ocean (seabed) in small caves and corners that make-up the rocks.

The depth of their habitat ranges between 20 and 500 meters. Atlantic wolffish love cold water, as long as it maintains a temperature between -1 and 11 ºC.

To survive these temperatures so low they keep their blood in continuous movement thanks to the natural antifreeze they have inside.

What Do Atlantic Wolffish Feed On?

This species uses its jaws to eat mollusks, crustaceans and echinoderms. It’s very rare to see them eating any other species ( such as cockles and some large clams, )which only occurs in extreme circumstances.

It’s important to point out that Anarhichas lupus has great hunting skills which helps them to control populations of sea urchins and green crabs.

How Atlantic Wolffish Reproduce?

The way how this species  fertilize its eggs is very different from other fish. Atlantic wolffish fertilize their eggs internally and the male remains in the nest, protecting them during about four months. When the young are large and strong enough to be independent, the male withdraws from its nest.

The eggs measure between 5.5 and 6 mm in diameter which makes of them the biggest of any species.  . Their color is opaque yellow and they are placed at the bottom of the ocean near the shoal waters. That is, the natural submerged ridges that are covered with sand.

You can also find eggs stuck in loose beds surrounded by seaweed and stones. It’s important to point out that this species needs to spend more than six years before reaching maturity.

The Atlantic Wolffish Conservation Satuts

According to scientific data, the population of Atlantic wolves has declined dramatically due to overfishing and bycatch. Morevoer, bottom trawlers also interrupt the underwater rocky habitat of this species when large nets are dragged across the ocean floor.

The networks catch different species (among them the wolffish) and are harmful to the benthic terrain and its inhabitants. Sometimes they use another type of heavy material that can also be harmful. Recreational fishing has also threatened the survival of the Atlantic wolffish.

According to data collected by the National Maritime Fisheries Service, since 1983, bycatch of wolffish by US fishing vessels has fallen by 95%..

In 1950 they were collected some data, where it was observed that 1,098 tons of this fish were landed, worth $ 137,008.

In 1970 the figure was 271.2 tons, in 1983 1,207 tons, in 1990 400 metric tons, and in 2002 it was 154 tons.

The latest data available from the NMFS (National Marine Fisheries Service) were in 2007 that indicated that the accidental capture of the wolffish was 64.7 metric tons, with a total value of $ 100,341.

Currently, the Atlantic wolffish is classified as a Low Concern Species by the NMFS. Low Concern Species are those species for which the National Oceanic and Atmospheric Administration of the United States together with the National Marine Fisheries Service have some concerns regarding status and threats, but for which there is insufficient information available to indicate the need for special protection laws.

On October 1, 2008, the Conservation Law Foundation (CLF), along with Dr. Erica Fuller and Dr. Les Watling, asked the NMFS of the United States for protection for the Atlantic wolffish under the species law.

The petition included protection for both the habitat and the animal as a species in the waters of the northwestern Atlantic of the USA.

They recommended that a habitat rating be established as critical for closing commercial and recreational fishing in those areas .. the development of catch and release protocols was also requested in addition to educational programs for Fishermen in the Gulf of Maine area and bans on possession.

On January 1, 2009, the NMFS announced a very positive resolution of 90 days, indicating that the petition was justified, which led to the initiation of a situation review that would lead to a decision on the list of species under the THAT.

In 2014, HELCOM (Convention for the Protection of the Marine Environment of the Baltic Sea Area) classified the population of Atlantic wolves in the Baltic Sea as endangered on the scale of the IUCN Red List

Enjoy nature responsible since it’s our responsability to preserve our  marine species…

Other Wolffish Species

Let’s meet other members of this family

Spotted Wolffish (Anarhichas minor)

The spotted wolffish (Anarhichas minor) is a marine fish belonging to the Anarhichadidae family. It can be found in the North Atlantic Ocean from the coasts of Russia and the Scandinavian Peninsula to Nova Scotia in Canada.

The population of this species declined approximately 90% between 1970 and 1990, particularly in the northern part of its range.

General description

Spotted wolffish have prominent canine teeth in front of both jaws; a heavy head with a rounded snout; Small eyes and a long body without pelvic fins.

It should be noted that this species also has a long dorsal fin; flexible spines; a small caudal fin; rounded pectoral fins; firm musculature; variable from pale green to deep brown with darker upper parts. Its maximum length is 1.8 m and its weight, 23 kg.

State of conservation

This species has been identified as «threatened» by the Committee on the Status of Endangered Fauna and Flora of Canada (COSEWIC). According to the 2001 assessment of COSEWIC, it has not been cataloged internationally with a certain degree of protection. So it’s not on the IUCN Red List.


Atlantic Wolffish: Artic oceanThe spotted wolffish lives in the Arctic Ocean and on both sides of the northern Atlantic Ocean from Labrador to the Barents Sea.

Its northern limit in Canada is Baffin Bay, although its presence is rare there. On the eastern side of the North Atlantic, it can be found in Greenland, Iceland and the Scandinavian coast.

Habitat and life history

This species lives on the high seas, in cold, deep waters, usually below 5 ° C and between 50  –800 m. They prefer coarse sand with stony areas nearby to build their nest-shelters. Egg laying occurs from summer to fall. Some 54,600 large eggs (up to 6 mm) are laid in the deep water in groups on the sea floor, and it’s stored mainly by males.  Anarhichas minor can live up to 21 years.


Its diet consists mainly of shell invertebrates found in the bottom, such as crustaceans and mollusks.


Overfishing and trawls are its biggest threat.

Let’s learn about this striking ocean

(Anarhichas denticulatus),  Northern wolffish or Rock turbot,

This is a fish that some consider charmingly ugly. They are distributed throughout the North Atlantic Ocean, north of Russia and in Scotland.

How is it?

It’s thick and heavy, with a large head and teeth on the front of the jaw that are smaller and sharper than those of the other two species of wolffish.

The shape of Anarhichas denticulatus and the size of its mouth and teeth allow it to capture mobile prey.

It can grow up to 145 cm in length and almost 20 kg in weight and stands out for having a more uniform body color than other wolf species, which ranges from gray to dark chocolate, sometimes with a light violet glow.

In the Canadian Arctic, the northern wolffish is found mainly in the Davis Strait, with its northernmost boundary in Baffin Bay. a few records report populations in the western Arctic, including as far west as Prince Patrick Island, NWT,

What does the northern wolfish eat?

They are demersal fish, that is, they feed on the seabed, whose sharp teeth and powerful jaws allow them to catch moving pelagic fish, starfish , sea urchins and crabs and other benthic creatures.

How do they live?

They are found on the high seas in cold waters below 5 ° C at depths ranging between the surface and 1200 meters.

These fish inhabit a wide range of bottom types, including sediments, rocks, coarse sand among others and use large rocks for shelter and nest building.

The adults make limited movements and are not migratory.

In addition, its life expectancy is 12 years, and when they are juveniles northern wolfish inhabit the depths of the ocean.

Sexual maturity comes from the age of five and the females lay around 46,500 eggs up to 8 mm in diameter that sink into the seabed, where they are kept in nests by the males until they hatch. It’s worth noting that the growth rate of this species is slow. .

Are Northern WolffishThreatened?

Its western Atlantic population declined dramatically during the 1980s, more than 90% from the late 1970s to the early 1990s.

There have been no direct studies of the factors responsible for the decreases observed in the population, but it’s believed that overfishing and habitat alteration have played a fundamental role.

This species is not the objective of the fishing industry, but mortality from accidental capture in trawls and longlines is considered a threat, and activities that alter the ocean floor such as trawling can damage their spawning habitat.

This fish is protected under the Canadian Species at Risk Act (SARA), and a recovery team for the northern wolf and also spotted wolffish is part of this study.

A recovery strategy and plan for both species has almost been completed.

The strategy provides a framework to improve the status of wolffish through a better understanding of their life history, their potential sources of damage and implementation of management measures, as well as the release of captured live specimens.

The plan also includes the Habitat management and educational activities designed to involve stakeholders and inform the public.

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Traira (Hoplias malabaricus)

Belonging to the family of the Erythrinidae, this species has a wide variety of common names depending on the locality where it’s found: guabina, traira, South American snakehead, tigerfish, tiger characin, tararura, haimara, wolf fish.

How is it?

The maximum length for this species is about 55 cm and the maximum weight is about 8 kg. The Trahira has a cylindrical body with a large mouth equipped with prominent teeth similar to that of a wolf. Its coloration is very variable, but it’s usually brown gray, with darker vertical strokes or a single horizontal strip.


The South American snakehead, is distributed throughout Central America and South America in most river systems in the following countries Argentina, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname , Trinidad and Tobago, Uruguay.

The country par excellence to find it is Argentina especially in the Paraná Delta. Las Niñas Lagoon, also in this country, is a recreational place for fishing families who come to spend the day and catch a Trahira because there are lots of them.

This species Occurs in diverse habitats from free flowing clear water streams, well up into the valleys, to slow turbid waters, water courses, irrigation and drainage ditches, and ponds on the plains.

It Rests in vegetation during the day and is active at night. Adults feed on fish while juveniles feed on crustacean and insect larvae shrimps and other small invertebrates.

The Trahira Spawns in pits located in shallow water at a temperature of about 26 ° C .

Males guard the nests even after the eggs have hatched. Live fish are difficult to handle and potentially dangerous because of their sharp teeth, strong jaws, and slippery bodies.

Fishing Trahira

This species of fish is very popular in sport fishing, the spinning and fly-fishing modality being the most used for it.   Traira is a fish with low oxygen consumption, which allows it to live in clean and very warm waters.

Due to the same reason, it hunts lurking, spending as little energy as possible. Taking advantage of its trunk-like format and its color this fish camouflages  in muddy beds or between submerged branches or roots, where it attacks its prey (insects, fish, batracios, frogs and even small birds) when they approach it without noticing its presence.

Let’s watch how they fish this species

Biodiversity and its Importance

Biodiversity is the variety of life forms on the planet (including terrestrial, marine ecosystems and the ecological complexes of which they are part), beyond the diversity within each species, between species and between ecosystems.

Biodiversity varies according to different ecological regions, and is much higher in tropical areas than in temperate climates.

Biodiversity is responsible for ensuring the balance of ecosystems around the world, and the human species depends on it to survive.

Ironically, the main threat to biodiversity is human action, which manifests itself through deforestation, forest fires and changes in the climate and the ecosystem.

The damage caused to biodiversity affects not only the species that inhabit a particular place, but also damages the network of relationships between the species and the environment in which they live.

Due to deforestation and fires, many species have become extinct before they could be studied, or before any action was taken to try to preserve them.

Biodiversity is not static, it’s dynamic; It’s a system in constant evolution, both in each species and in each individual organism.

The importance of biodiversity can be synthesized in two essential features. On the one hand, it’s the fruit of nature’s millions of years of work, so its value is incalculable and irreplaceable.

On the other, it’s a guarantee for the correct functioning of the system that forms living beings, together with the environment in which they live and to which they contribute for their survival.

In this way, we can affirm that biodiversity is not only significant for human beings, but that it’s essential for the life of the planet, so we must try to preserve it.

The biodiversity of the species provides us with necessary goods such as food or oxygen, provides us with raw materials that favor economic development, produces energy that we use as fuel, is the origin of some medicines and, finally, but no less important , we are filled with the retina of beautiful landscapes that we can enjoy.

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