Fish
Spurdog
Squalus acanthias · also called spiny dogfish, piked dogfish
Over a sandy bank in the North Sea, a pack of spurdogs sweeps through a shoal of herring, each slim grey shark carrying a sharp spine in front of its fins.
Overview
The spurdog, Squalus acanthias, is a Vulnerable small shark of cool temperate waters, sold for years as rock salmon in fish and chips. Its venomous spines, packs, and very long pregnancy made it vulnerable to the heavy fishing that devastated north-eastern Atlantic stocks.
A shark with a very slow life
With a pregnancy lasting nearly two years and late maturity, the spurdog can take decades to recover from overfishing, and protection has been essential.
Status
Vulnerable, with severe declines in the north-eastern Atlantic.
Spurdog: common questions
Is the spurdog venomous?
It has a sharp, mildly venomous spine in front of each of its two dorsal fins, which it uses to defend itself.
How long is a spurdog pregnant?
It carries its young for around two years before giving birth to live pups, one of the longest pregnancies of any vertebrate.
Why is the spurdog threatened?
It was heavily fished, and because it matures late and has few young, stocks cannot recover quickly.
Where is the spurdog found?
It lives in cool temperate waters of the North Atlantic, the North Pacific, and the Southern Hemisphere.