Cartilaginous fish · Squaliformes · Squalidae

Spurdog

Squalus acanthias

Vulnerable

It faces a high risk of extinction in the wild over the medium term. See full glossary

The spurdog is a small shark of temperate waters with two venomous spines in front of the dorsal fins. For decades it was one of the most heavily fished sharks in the world, and its biology left it unable to withstand that: it lives more than seventy years, does not breed until it is past fifteen and its gestation lasts almost two years.

Weight

3 kg – 10 kg

Size

70 cm – 1.6 m

Lifespan

75 years

Diet

Carnivore

Feeds mainly on other animals.

Activity

Irregular activity

Active at irregular times, by day or night depending on circumstances.

Social structure

School

Gathers in coordinated schools, typical of fish.

Sighting difficulty

Moderate

Fun facts

  • reproducciónIt can have one of the longest gestations known in any vertebrate, running to almost two years in some populations.
  • Its gestation lasts close to two years, one of the longest of any vertebrate, and it does not breed until it is past fifteen: a biology incompatible with the industrial fishery that decimated it.
  • It was one of the most heavily fished sharks in the world: for decades it was the main ingredient of British fish and chips and of European shark meat, with catches of hundreds of thousands of tonnes.
  • Its dorsal spines are coated in an irritant secretion, and it forms enormous shoals segregated by sex and size that travel thousands of kilometres.

Life cycle & biology

Skeleton type
Vertebrate - cartilaginous skeleton (fish)
Habitat & environment
Temperate coastal and shelf waters of every ocean, including the Bay of Biscay and the Mediterranean
Birth weight
22 - 33 cm at birth
Size at birth
22-33 cm at birth; its gestation, of 18 to 24 months, is among the longest of any vertebrate
Sexual maturity
21 years
Gestation / incubation
22 months of gestation
Litter / clutch size
8

Sources consulted: https://www.iucnredlist.org/ | https://animaldiversity.org/ | https://es.wikipedia.org/

Related species

Other species in the catalogue with the most in common with Spurdog — same habitat, park, country, tags or family.

How to help

The spurdog is classified as vulnerable. Organizations such as UICN, WWF y Wildlife Conservation Society work specifically on its conservation and that of its habitat; looking into their programs is a good starting point if you want to get involved.

It's documented in 18 real protected areas — part of why protecting these places matters for its conservation.

Keep exploring

Based on what we already know about spurdog.

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