Skip to main content

Spiny Dogfish

Squalus acanthias

Distinguishing Characteristics

Illustration of a spiny dogfish shark showing important characteristics
  • Blueish-gray back, white spots on sides and a white belly
  • Slender body with a long, narrow and pointed snout
  • One spine in front of each of the two dorsal fins
  • First dorsal fin starts just behind pectoral fin
  • Large spiracles present
  • No anal fin
  • Pale caudal fin with white edge and black blotch on upper lobe
  • No interdorsal ridge

Similar Species: Cuban dogfish, S. cubensis (both dorsal fins with long spines, dorsal origin anterior to pectoral free tips and lateral keels on caudal peduncle); Roughskin dogfish, Cirrhigaleus asper (both dorsal fins with very long spines, large spiracles and short caudal fin);  Shortspine dogfish, S. mitsukurii (longer snout and rarely has spots throughout body); Smooth dogfish, M. canis (has anal fin and lacks dorsal spines)


Maximum size about 3.5-4 feet in length. Females reach maturity at approximately 12 years and males mature around 6 years of age (around 2 feet for both sexes) and is estimated to live 54+ years.


A highly migratory species, they are known to travel to Greenland waters during summer months and spend the fall/winter in sub-tropical areas near Georgia.  Although rarely found in Florida waters, they could be found offshore or in coastal areas, usually near the bottom, but known to congregate in large schools and can tolerate brackish water.


Feeds on a variety of small schooling fishes including herrings, menhaden, and mackerels. Also consumes flatfish, squids, shrimps, crabs, and octopus.


Thought to have the longest gestation period of all vertebrates (up to 24 months). Live young are born head first with cartilaginous sheaths covering the spines to protect the mother. Broods contain 6-15 pups. Size at birth 8-13 inches.

Additional Information

Prohibited from commercial or recreational harvest in Florida. Commercially targeted for meat and liver oil in U.S. North Atlantic waters. This species poses little threat to humans; however, caution should be used while handling due to their sharp dorsal spines.

Recreational Regulations


Image Credit: © Diane Rome Peebles