Spearfishing Stats

Taxonomy

Rarity

The Pacific spiny dogfish is abundant across a very large range and almost absent from a southern California diver's life, and the reason is temperature.

The species runs from Korea and Japan north through Russia and the Bering Sea, and down the American side from the Gulf of Alaska through British Columbia and Washington to southern Baja California. On paper that covers this entire site. In practice the animal prefers water between 45 and 59 degrees Fahrenheit and actively moves along the coast and up and down in the water column to stay in that band. Southern California is warmer than that near the surface, so the dogfish here are deep. This is a Pacific Northwest shark that happens to have a southern edge.

The International Union for Conservation of Nature assessed it in 2016 and lists it as Least Concern. California treats it as a federal groundfish: 10 fish inside the general 20-fish daily limit, no size limit, open year-round at any depth, with one hard exception. Inside the Groundfish Exclusion Areas the species may not be taken or possessed at any time.

Regulations

CDFW rules verified 2026-09-08

Seasonality

Edibility

Location

Adults live on or near the bottom between about 49 and 4,080 feet, and are usually between 164 and 656 feet. Juveniles do something different: they hold in open water in the top 82 feet and only settle to the bottom as they mature. Dogfish may be alone or in groups.

The diet is opportunistic with no particular target. Larger animals eat mostly fish, and the rest of the menu is squid, octopus, jellyfish, comb jellies, shrimps, krill, small shrimp-like crustaceans called amphipods, and bristle worms. That is the list of a predator that eats whatever is in front of it.

The name comes from the equipment. A spiny dogfish carries a spine in front of each of its 2 dorsal fins, and the first one is described as moderate in size and narrow at the base. FishBase lists the species as harmless to people. Popular accounts often describe these spines as venomous; that was not verified for this entry, so what is said here is simply that the spines are there and are worth handling carefully.

Spearfishing Brief

This is a legal species that a southern California breath-hold diver will almost certainly never see, and the entry says so rather than inventing an approach.

Finding one rates a 5, and the reason is entirely depth and temperature. The water this shark wants sits below the range a diver on one breath can reach off southern California. Further north, where cold water comes to the surface, the picture changes completely, and this is a species the site's Pacific Northwest spots have a genuine claim on.

The shot rates a 2 if the encounter happens at all. This is a slender 4 foot shark with no speed and no aggression, and a short speargun is more gear than the job needs. The one thing to handle deliberately is the pair of dorsal spines.

The regulation to know is not the bag limit but the closure. Spiny dogfish are open in all depths year-round, except inside the Groundfish Exclusion Areas, where they may not be taken or possessed at any time. That is a place-based rule rather than a number, and it is the kind that gets people cited.

On the table, sources are blunt: edible, but not appreciated. There is also a specific health caveat attached to this species that does not apply to most sharks in this Ichthyopedia. Because large individuals accumulate mercury, published guidance is to eat only fish under about 24 inches. On top of that is the handling rule that applies to every shark: they hold urea in their tissue and blood, it turns to ammonia after death, and the fix is to bleed the animal at once, wash it in seawater and ice it.

Deep Dive

The number that defines this species is 35.5, and it is a number about patience.

Male Pacific spiny dogfish reach breeding size at a median age of 18.5 years. Females reach it at a median age of 35.5 years. A female dogfish spends 3 and a half decades growing before she produces a single pup, and then rests a year or more between pregnancies for the rest of her life. There is no fish in this Ichthyopedia that takes longer to start. A market squid, at the other extreme, completes its entire existence in 9 months.

This is what fisheries scientists mean by low productivity. A species that cannot replace a removed adult for 35 years does not respond to good management on a human timescale, whatever the current conservation listing says.

There is a naming problem attached to this shark that is worth knowing about, because it will trip up anyone reading older material. Until recently, the spiny dogfish of the North Pacific was treated as the same species as the Atlantic one. In 2010 a study by Ebert and colleagues resurrected an older name, and the North Pacific animal became its own species again. Every California source written before that calls this fish by the Atlantic name. The practical consequence is that a great deal of the famous dogfish biology in circulation, including the often-quoted claim that they live to about 100 years and carry their young for 2 years, belongs to the Atlantic species and has not been established for this one. FishBase carries no maximum age for the Pacific animal at all.

The last note is a small piece of industrial history. Dogfish liver is rich in oil, and around Nanaimo in British Columbia that oil once served as fuel for mine lamps. A fish nobody wanted to eat was still worth catching, and a shark that takes 35 years to breed was being rendered for lamp oil long before anyone had measured how long it took to replace one.

Where to Find Them

Beaches whose habitats match this species

Matched by habitat: a beach is listed when its biome tags overlap this species' biomes.