The Pacific spiny dogfish is a common species of the Squalidae family of sharks and are among the most abundant species of sharks in the world. This species is closely related to Squalus acanthias and for many years they were treated as a single species. Recent research, using meristic, morphological and molecular data led to the resurrection of Pacific Spiny Dogfish as a separate species. The American Fisheries Society recommends the common name "Pacific Spiny Dogfish" for Squalus suckleyi over alternatives such as "Spotted Spiny Dogfish" and "North Pacific Spiny Dogfish" and "Spiny Dogfish" for Squalus acanthias.
The maximum length of a Pacific dogfish can be 130 centimetres (51 in), and they can live up to 100 years. Squalus suckleyi has a slower growth rate, larger maximum size, and later maturity compared to Squalus acanthias species. The slower growth rate and time of maturity could be related to the colder temperatures these sharks face. Pacific spiny dogfish prefer to be in temperatures ranging from 7 to 15 °C (45 to 59 °F). Dogfish are found all over the world, but the Pacific spiny dogfish are found mostly in the North Pacific Ocean. These areas range from Korea to Japan and Russia, as well as the gulf of Alaska down to Baja, California. They are known to be piscivores, eating other fish. Additionally, they are known to consume octopus, squid, and crustaceans.
Squalus suckleyi have a slow reproduction rate compared to other sharks, with their gestation period being roughly around two years. This makes the Pacific dogfish more vulnerable to threats since they take longer to reproduce.