Spurdog
Squalus acanthias
Also known as: Spiny Dogfish, Piked Dogfish, Picked Dogfish, Picky Dog, Dogfish
About This Species
This small, slender shark forms large schools in cold temperate coastal and continental shelf waters across the North Atlantic, North Pacific and parts of the Southern Hemisphere, often moving inshore seasonally to feed on small fish and invertebrates. It can sometimes be seen from boats or in clear shallow water where schools come close to shore, particularly during seasonal inshore migrations, and divers occasionally encounter loose aggregations over rocky or sandy bottoms. Look for its slim grey-brown body, white spots along the back, and the sharp spine in front of each dorsal fin that gives it its common name.
Ethical Viewing Guidelines
- Give this species a wide, passive berth of at least several metres and avoid touching or restraining individuals, since it is listed as globally Vulnerable and has suffered steep population declines from historic overfishing in many regions.
- Catch limits, protected status and handling rules for this species vary significantly by country and fishery, ranging from strict no-take protections to regulated commercial quotas, so anyone encountering it, whether diving, boating or fishing, should check local regulations rather than assume a single rule applies.
- Where it is caught incidentally, minimising handling time and returning it to the water quickly gives the best chance of survival given its slow growth and low reproductive rate.
Seasonal Activity
210,305 sightings · 2000–2026
Citizen science records via GBIF
Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Elasmobranchii
- Order
- Squaliformes
- Family
- Squalidae
Photo
(c) Malcolm Francis, some rights reserved (CC BY-NC), uploaded by Malcolm Francis
CC-BY-NC-4.0
Occurrence data from GBIF.