Spotted wolffish

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Onglets

Description

Distinguishing features

The spotted wolffish gets its name from the fact that it has enormous teeth and numerous brown spots on its body. Its long, eel-like body is brownish-grey and sometimes yellowish, and it may have olive-green undersides.

Its head is rather large, so as to hold its very strong jaw, designed to break the shells of its prey. It has bulbous eyes and also a large mouth, with wide, fleshy lips.

The spotted wolffish has no pelvic fins. To swim, it undulates its body and its long dorsal fin, which runs from its head to its tail.

Reproduction

These fish reach sexual maturity around the age of 7 to 10 years, females being more precocious than males. Mating occurs between July and January, peaking in October.

Fertilization is internal and the female produces 8,000 to 50,000 eggs annually. The male forms the eggs into a cluster, which he protects and fans to keep them well oxygenated.

After incubation, the eggs hatch and tiny wolffish fry that resemble the adults, emerge. They grow very quickly, twice as fast as Atlantic wolffish fry.

Diet

The spotted wolffish is a carnivore with special adaptations that allow it to feed on hard-shelled animals.

It uses its canine-like teeth to grasp its prey: sea urchins, sea stars, various molluscs and crustaceans. It also has one or two rows of large, flat, molar-like teeth on its palate that allow it to grind the shells of its prey.

Once it has ground up and spit out the bits of the shell, it can eat the flesh. However, an examination of the contents of wolffish stomachs suggests that they do in fact swallow many of the broken shells of their prey (mussels, crabs, urchins, etc.)

Predators

Wolffish tend to hide under and between rocks, where they are protected from their many predators. They are frequently attacked by cod and Greenland sharks.

Commercial fishing of spotted wolffish is now prohibited almost everywhere, but they can still sometimes be found on diners’ plates, since the flesh is highly prized. These spotted wolffish come from Iceland, as a rule, but they may also be bycatches (fish accidentally caught in nets used for catching other species).

Studies have shown that this species could well be farmed, and numerous teams in Norway, Iceland, Sweden and even here in Quebec have worked on maintaining and breeding the fish in captivity, with the goal of producing it commercially.

Habitat

Spotted wolffish frequent the waters of the North Atlantic, from the Labrador Shelf to the Scotian Shelf and the Gulf of St. Lawrence. In Quebec, these fish are found mainly in the northern part of the Gulf of St. Lawrence, between Anticosti Island and Blanc-Sablon.

These fish are not particularly demanding, and are found almost everywhere, over all types of bottoms, at depths of 25 to 750 m, provided that the water temperature is between 2 and 5 °C.

Ecology, behaviour

Spotted wolffish lack a swim bladder. This means that they must stay near the bottom, because they are heavier than water and sink as soon as they stop swimming. They are known as a demersal (bottom-dwelling) species.

These wolffish live at temperatures near freezing. To survive the cold, they can synthesize proteins with antifreeze properties – an ability that greatly interests the medical, pharmacology and food industries.

Their spotted skin may be turned into an attractive form of leather used in furniture, clothing and bookbinding.

All wolffish species (spotted, Atlantic, northern and others) are experiencing drastic population declines. Everything points to this disturbing trend being linked to current bottom-fishing techniques. Trawl nets dragged along the bottom are known to destroy the ecosystem of the ocean bottom where they are used. Wolffish need shelters on the bottom to hide in, and especially to hatch their eggs.

French name

Loup tacheté

Scientific name

Anarhichas minor

Phylum

Chordata

Class

Osteichthyes (bony fish)

Order

Perciformes

Family

Anarhichadidae

Size

150 cm

Weight

23 kg

Life span

21 years

Status

Threatened species (COSEWIC 2001)

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