Spearfishing Stats

Taxonomy

Rarity

Pacific bluefin tuna are the largest and most valuable fish a California diver can legally hunt, and 15 years ago the species looked like it might not survive the century. Heavy fishing through the late 1990s and 2000s drove the spawning population down to about 2 percent of what it would be with no fishing at all, a low it sat at from 2009 through 2012. NOAA Fisheries declared the stock overfished in 2013. In 2016 a petition asked for it to be listed under the Endangered Species Act, and the status review that followed found the population large enough to avoid extinction but did not make anyone comfortable.

What happened next is the rarest kind of fisheries story, which is one that worked. International catch limits came in through 2 tuna commissions starting in 2011 and 2012. The rebuilding goal was to get the spawning population back to at least 20 percent of its unfished level by 2034. It passed that mark in 2021, roughly a decade early, and by 2022 the spawning population stood at 23.2 percent, the first time it had ever been above the level associated with the maximum sustainable catch. The 2024 stock assessment found the species neither overfished nor subject to overfishing. The IUCN moved it from Vulnerable to Near Threatened in 2021 on the strength of that data. Near Threatened is still not a comfortable status, and the assessment rests on catch limits holding, but a fish that was at 2 percent in 2012 is now above its target.

For a diver in southern California, the practical result is that bluefin have become findable. From roughly April through December, waves of them move through the water between south of San Diego and north of San Clemente Island, and fish of 200 to 300 pounds are ordinary in that run, with some over 400.

Regulations

CDFW rules verified 2026-09-06

Seasonality

Edibility

Location

Pacific bluefin live in the North Pacific and cross it. The eastern side of the range runs from the Gulf of Alaska down through southern California and Baja California; the western side runs from Sakhalin Island south to the northern Philippines. Only 4 records exist from south of the equator. The species is oceanic, holding anywhere from the surface to about 1,800 feet, and it schools by size, so the fish in a given group tend to be similar to each other. Along the North American coast the population pushes north between June and September.

Off southern California the fish concentrate where the water changes. Divers and boat crews look for temperature breaks and current edges, the lines where 2 bodies of water meet and bait piles up along the seam, in water between 60 and 68 degrees. Diving birds, surface boils and patches of foaming white water mark a school feeding at the top. Below the surface the school is invisible without electronics, which is why sonar is standard equipment on a boat hunting them.

Adults reach maturity at about 5 years. Where the eastern Pacific fish spawn, and when, is not something the published record settles clearly, so it is left unstated here rather than guessed at. Growth and lifespan are better documented. A typical adult is close to 5 feet and 130 pounds, the largest ever recorded was about 9 feet 10 inches and 990 pounds, and NOAA Fisheries puts the maximum age at 26 years with an average near 15.

Spearfishing Brief

Bluefin sit at the top of the difficulty scale, and they get there on the shot rather than the search. Overall difficulty is 5.

Finding them rates a 4. The fish are offshore, they cover ground fast, and a diver realistically needs a boat, sonar, and someone aboard who knows the current season. Birds, boils and foam give away a feeding school at the surface, and the schools stack along temperature breaks and current edges, but none of that is available from a beach. Divers report the best encounters at first light or in the last hour or 2 before sunset, and prefer the new moon, when weaker tides move the bait more slowly. The reason this is not a 5 is that when the run is on off San Diego and the islands, people who know the water find fish repeatedly.

The shot rates a 5, the top of the scale, and belongs alongside white seabass and California halibut as one of the site's hardest. It is a different kind of 5 from either of those. The approach is an intercept, not a stalk. The boat gets ahead of the direction the school is traveling, divers slide in quietly and wait in the path, and the fish either come through or they do not. Everything happens in seconds, which is why divers describe the time between spotting fish and getting bodies in the water as the thing that decides the day. The shot itself is taken behind the pectoral fin into the body cavity, or into the spine from above, and it is led, meaning it goes ahead of the fish rather than at it. Then the diver gets out of the way, because the fish runs immediately and hard. The floats are watched from the surface until the fish tires, and only then does anyone close for a second shot.

The gear reflects all of that. The gun is a bluewater model, 60 to 70 inches long, roughly 150 to 180 cm, with 4 or 5 bands driving a shaft of at least 8 mm and preferably 9 to 9.5 mm. The point is a slip tip, which detaches and turns sideways inside the fish so the shaft cannot be thrown. Nothing is attached to the gun. A breakaway rig runs 75 to 150 feet of float line through a bungee section to high-pressure inflatable floats, which take the run and wear the fish down. Divers also chum, freezing oily fish such as mackerel and sardine into blocks and hanging them over the side in a mesh bag so the melt trails oil and particles down the current. This is an advanced pursuit with real consequences, and the community treats it that way, requiring a strong breath-hold, comfort at 30 to 60 feet, and dedicated safety divers rather than a group of friends taking turns.

California allows 2 bluefin per person per day, and that limit is separate from and in addition to the general 20-finfish limit, which is unusual. There is no minimum size and no closed season. There is a rule about what happens after the fish is on the boat: any tuna filleted at sea or brought ashore as fillets south of Point Conception, Santa Barbara must be bagged individually with the species name on the bag, and cut into exactly 6 pieces with the skin left on, being the 4 loins, the collar taken off as 1 piece with both pectoral fins still attached, and the belly cut to include the vent with both pelvic fins attached. That rule exists so a warden can identify a fish that no longer has a head.

The meat is the reason all of it happens. Bluefin flesh is dark red and heavily marbled with fat, closer to a beef steak in firmness and appearance than to anything else that comes out of the ocean, and it turns off-white when cooked. The fat is what makes it the benchmark sushi and sashimi fish worldwide. It is also a good source of protein, selenium, vitamin B6 and omega-3 fatty acids, which is not why anyone shoots one.

Deep Dive

A Pacific bluefin is a warm animal in cold water. Most fish run at the temperature of the sea around them. Bluefin do not. They hold the swimming muscle, the eyes, the brain and the gut above the temperature of the water around them, by as much as 38 degrees Fahrenheit, using a heat exchanger built into the blood supply. Warm blood leaving the muscle on its way back to the heart runs alongside cold blood arriving from the gills and hands its heat across instead of losing it, and in bluefin that transfer is close to 99 percent efficient. Separate versions of the same structure sit around the brain and the eyes. Biologists call the whole arrangement regional endothermy, because the fish is not warm all over, only in the parts that matter.

The payoff is that a bluefin can chase prey into cold water without its muscles slowing down, and can hunt with warm eyes and a warm brain in water a cold-blooded fish would be sluggish in. It is what lets a bluefin cross an entire ocean. The ability shows up early. Research published in 2025 found that Pacific bluefin begin holding their own body temperature as juveniles, from a body length of about 8 inches, driven by an unusually high rate of heat production at that stage.

Every fish in this family is built on the same plan, from a 990-pound bluefin down to a 12-inch Pacific mackerel. The mackerel a diver ignores in a southern California kelp bed is the same basic animal, scaled down and left at sea temperature.

What bluefin eat is mostly what a California diver already knows. NOAA Fisheries lists squid along with sardine, anchovy, herring and mackerel, plus the occasional crustacean. That is the entire forage base of the southern California coast, which is why a bluefin run and a good bait year tend to be the same news. It is also why divers hunting them use frozen blocks of mackerel and sardine as chum. The fish are being offered exactly what they came for.

The management story behind the recovery is unusually specific for a fish this size. Pacific bluefin are managed by 2 international commissions, the Inter-American Tropical Tuna Commission on the eastern side of the ocean and the Western and Central Pacific Fisheries Commission on the other, with the scientific work done by an international committee that assesses the North Pacific tuna stocks. Domestically, NOAA Fisheries implements the regulations with the Pacific and Western Pacific Fishery Management Councils under the Magnuson-Stevens Act, the federal law that governs American fisheries. The recovery came from that structure agreeing to cut catch, particularly catch of young fish, starting in 2011 and 2012. The stock passed its 2034 rebuilding target in 2021.

California's own rule reflects how differently this fish is treated from its relatives. Bluefin gets a limit of 2 that sits on top of the general daily limit, so a bluefin does not use up 1 of the 20 fish an angler or diver may otherwise take. Albacore is treated the same way, at 10 south of Point Conception, Santa Barbara and 25 north of it. Skipjack has no limit at all. Yellowfin, bigeye and every other tuna get 10 fish that do count against the general limit. Those 4 different treatments in a single section of the regulations are a rough map of how much pressure the state thinks each species can absorb.

One last thing about the size of these animals. A 200-pound bluefin on a spear is not a fish being landed, it is a fish being followed until it stops. The entire float system exists because there is no version of this where a person holds on. That is the practical meaning of a 990-pound maximum and a body designed to swim across an ocean.

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.