Spearfishing Stats

Taxonomy

Rarity

The blue shark is probably the most widely distributed cartilaginous fish on the planet. It lives in temperate and tropical water in every ocean, and in the eastern Pacific it runs from the Gulf of Alaska to Chile. Anyone who has taken an offshore trip out of southern California and seen a shark has most likely seen this one.

Being everywhere has not protected it. The International Union for Conservation of Nature assessed the species in 2018 and lists it as Near Threatened, and it sits on Appendix II of the international wildlife trade treaty. The criteria behind that listing point at a measured drop in abundance driven by how heavily the species is caught, rather than at habitat loss or any other cause.

California allows 2 per person per day, year-round, with no size limit, under the same rule that covers shortfin mako and thresher.

Regulations

CDFW rules verified 2026-09-08

Seasonality

Edibility

Location

Blue sharks are an open-ocean animal that comes close to land where the land runs out quickly. FishBase describes them as oceanic but findable close inshore where the continental shelf is narrow, which is a fair description of the southern California coast, and they have even been recorded inside estuaries. They usually hold in the top 720 feet and have been recorded to roughly 3,550 feet.

Temperature sets the boundary. Blue sharks live between about 45 and 70 degrees Fahrenheit, which is a cooler band than the shortfin mako's, and it is why the 2 species do not overlap as neatly as their shared bag limit suggests.

They travel absurd distances. One blue shark tagged in New Zealand was recaptured 1,200 kilometers off the coast of Chile, which is roughly 750 miles, and that was only the distance between 2 known points rather than the route it swam.

The diet is broad and includes some things that say a lot about the animal. Blue sharks eat herring, hakes, cod, haddock, pollock, mackerel, butterfish, sea raven and flounders, along with small sharks, squid and pelagic red crabs, the swarming crustaceans that wash onto southern California beaches in warm years. They also eat dead whale and dolphin, the occasional seabird, and garbage. That last item is in the scientific record, not an editorial comment.

Spearfishing Brief

The blue shark is legal in California at 2 a day with no size limit, and it is the shark a spearfisher is most likely to meet offshore.

Finding one rates a 4. Blue sharks are common on offshore trips out of southern California, particularly where chum is in the water, and they are curious enough to come and look. What keeps this off a lower number is that it is still an offshore encounter requiring a boat and blue water. No shore diver meets a blue shark.

The shot rates a 4, and here the difference from the shortfin mako matters. FishBase classifies both as traumatogenic, meaning documented to cause injury to people, but the language differs: the mako is recorded as responsible for unprovoked attacks on swimmers and boats, while the blue shark is described only as potentially dangerous. Blue sharks are also slower and lighter, topping out at 13.1 feet and 454 pounds against the mako's 1,115. A big gun with a detachable point and a breakaway float line is the rig, and the animal deserves respect rather than fear.

The number worth weighing is the bag limit against the assessment. A species can be abundant, widely distributed, and declining at the same time, and the blue shark is the clearest case of that in this Ichthyopedia.

On the table, the honest answer is that nobody consulted for this entry says. The scientific record notes that blue shark is marketed fresh, dried, salted and frozen, that the meat is eaten, the hide goes to leather and the fins to soup. No source read here rates the eating quality, so this entry does not either.

Deep Dive

The blue shark is built for covering ground on very little fuel, and every part of it shows that.

Start with the shape. This is a slim, long-snouted shark with unusually large eyes and pectoral fins that are long and narrow rather than broad. Where the shortfin mako is a thick muscular cylinder, the blue shark is long and slim. The upper teeth are curved triangles with saw edges, and there is no ridge of skin running between the 2 dorsal fins, which is the quickest way to separate this species from several similar requiem sharks.

The color is the name and it is unusual among fish. Most open-ocean animals are some version of gray or steel. A blue shark is dark blue across the back, bright blue along the sides, and white underneath, with dusky tips on the pectoral and anal fins.

Reproduction is where the species diverges sharply from the mackerel sharks. A mako or a white shark grows its pups inside the mother with no placenta, feeding them on unfertilized eggs. A blue shark builds a placenta and feeds the pups directly, the way a mammal does. The payoff is numbers. Gestation runs 9 to 12 months and a usual litter is 15 to 30 pups, each 14 to 17 inches long at birth. Recorded maximum litters run far higher, and the published figures disagree with each other at the top end, with counts of 63, 80 and 135 all appearing in the literature. Even the low end of that spread is an order of magnitude past what a mako produces in a cycle 3 times as long.

Producing that many pups is what separates this species from the mackerel sharks on paper, and it is worth holding alongside the Near Threatened listing rather than instead of it. A shark can be both highly productive and in measured decline, and this one is.

One measured oddity has no explanation attached to it in the record, and it is worth stating carefully for that reason. Female blue sharks have a thicker skin layer than males of the same size. The observation is published and repeatable. The source consulted here reports the difference and does not say what causes it, so neither does this entry.

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.