Cartilaginous fish · Squaliformes · Squalidae
Spurdog
Squalus acanthias
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/
Where to find it
See its range on the interactive mapBest time: From autumn to spring in temperate and cold waters; it forms very large schools, segregated by sex and by size.
Where to watch it
Parques y spots de buceo donde se ha documentado esta especie — se muestran 20 de 153 documentados.
Related species
Other species in the catalogue with the most in common with Spurdog — same habitat, park, country, tags or family.
VulnerableSperm Whale
Physeter macrocephalus
Porbeagle
Lamna nasus
VulnerableGrayfish
Alopias vulpinus
Greenland Shark
Somniosus microcephalus
VulnerableCod
Gadus morhua
Haddock
Melanogrammus aeglefinus
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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