Spearfishing Stats

Taxonomy

Rarity

Diamond turbot are one of the most numerous fish in southern California bays and sloughs, which is the California Department of Fish and Wildlife's own description. They are very common in Los Angeles Harbor, in San Diego Bay, in Mission Bay, and in the coastal lagoons up and down the southern coast. The IUCN lists the species as Least Concern, assessed in 2021. There is no minimum size, no closed season, and no species-specific bag limit in California, so the general rule of 10 fish inside a 20-fish daily total applies. The species is also not a federally managed groundfish, which matters more than it sounds: the depth restrictions and seasonal closures that govern rockfish, lingcod and the sole family do not reach diamond turbot at all.

What keeps this from being a fish everyone knows is that it is hard to see and modest in size. A diamond turbot tops out around 18 inches and 4 pounds, and the ones a diver actually meets in a bay are 12 to 15 inches. Those are old fish. CDFW puts the maximum lifespan at about 9 years and a 12 to 15 inch fish at roughly 8 or 9 years old, which means a keeper-sized diamond turbot has been living on that mud flat for most of a decade.

Regulations

CDFW rules verified 2026-09-06

Seasonality

Edibility

Location

The species ranges from Cape Mendocino in northern California south to southern Baja California, with a separate population isolated in the Gulf of California. Within that range it wants quiet water over soft bottom. CDFW describes the habitat as coastal waters, bays and sloughs, on mud or sand, often near some kind of structure. Depth runs from about 4 to 60 feet with records below 150, and the shallow end is where the fish concentrate. In practical terms that means back-bay flats, the soft bottom off a harbor channel, the edges of an eelgrass bed, and the shallow lagoons behind the beaches.

The name describes the shape. Diamond turbot are right-eyed flatfish, meaning both eyes end up on the right side of the head, and the body is a near diamond rather than the long oval of a halibut. A fresh fish is brownish green on the eyed side with pale blue spots scattered across it, a color that goes nearly black once the fish dies. The blind side underneath is white with a yellow patch around the mouth. The reliable identifying mark is the lateral line, the row of sensory pores along the side of a fish that senses water movement. On a diamond turbot, a long branch of it runs up onto the back, which no other local flatfish does.

Feeding is a daytime activity, and the diet is buried food. Diamond turbot eat marine worms, clams, shrimp, crabs and other small crustaceans, and they take a particular thing that is worth naming: the siphons of clams. A buried clam extends a pair of tubes to the surface of the sediment to breathe and to feed, and a diamond turbot crops them off. Spawning runs from September through February and peaks between November and January. Fish mature in their second or third year.

Spearfishing Brief

Diamond turbot are the California halibut problem in miniature. Overall difficulty is 4, and every bit of it is in the search.

Finding one rates a 4. This is a flat brownish-green fish lying on brownish-green mud in bay water that is rarely clear, and it is spotted rather than solid, which breaks up the outline further. A diver can pass directly over one and see nothing. What keeps it a rung below halibut, which this Ichthyopedia rates a find-driven 5, is that diamond turbot are far more numerous and live in shallower, more confined water. The odds of having several under a diver on a given bay flat are good. Seeing them is the problem. The search is the same one that works on halibut: stop scanning for a fish and start scanning for the wrong shape, an outline in the sediment, a raised eye, the edge of a body where the bottom should be flat.

The shot rates a 1, the floor of the scale. A flatfish on the bottom holds position until a diver is right on top of it, which is exactly why the search is the whole hunt. A pole spear or a short speargun covers the range, because there is no range. No spearfishing account for this species turned up anywhere, so the weapon note is reasoned from the habitat rather than taken from a published one.

There is a legal complication specific to this fish, and it is not the state rules. Diamond turbot live in bays and harbors, and city and harbor authorities set their own rules inside those waters that are separate from state fishing regulations. Spearfishing is prohibited outright in some California harbors. A diver planning to hunt this species in a named bay has to check the local ordinance, not just the state booklet.

On the table, CDFW calls diamond turbot excellent eating, and then names the catch in the same breath: the fish is small and the skin is tough, which makes preparation harder than it should be. Both halves are true. The meat is clean white flatfish, and a 12 to 15 inch fish yields 4 small fillets that most people would rather not fight the skin for, so cooking the fish whole is the common answer. Anglers take them on small hooks and light tackle with clam or ghost shrimp, mostly in Mission, Newport and San Francisco bays.

Deep Dive

A flatfish starts life the right way up. A newly hatched diamond turbot is a normal larval fish, upright, with an eye on each side, swimming in open water. Then it changes. One eye migrates across the top of the skull to join the other, the skull itself twists, the body flattens, and the fish settles onto the bottom and lies down on its now-blind side for the rest of its life. Diamond turbot are righteye flounders, so both eyes end up on the right side, and the pigment follows, dark on top and white underneath. That consistency is worth contrasting with the California halibut, which is about as likely to finish left-eyed as right-eyed, an oddity in the group. A diamond turbot is never in doubt.

The clam siphon habit is worth pausing on. A siphon is the tube a buried clam pushes up through the sediment to draw in water for oxygen and food, and it is the only part of the animal a predator can reach without digging. Cropping siphons is a way of eating a clam without ever getting the clam. It is not fatal to the clam, which regrows the tissue, so the same bed can feed the same flatfish repeatedly. That kind of feeding only works for an animal that lies flat on the bottom and can wait, which is what the entire body plan of a flatfish is for.

The scientific name of this species is currently in dispute, and a reader who looks it up will notice. FishBase and the Smithsonian's eastern Pacific fish database now place it in the same genus as the other turbots, which is the name in the frontmatter above. CDFW, the U.S. Fish and Wildlife Service, and the U.S. Geological Survey all still publish it in a genus of its own, under the older name. This entry uses the name FishBase accepts, because that is the rule this Ichthyopedia follows, but nearly every California-facing page a reader finds will use the other one. Nothing about the fish changed. Only the judgment about how closely it is related to its neighbors did.

The last thing worth knowing is the age. A diamond turbot lives about 9 years, matures at 2 or 3, and the fish a diver considers worth taking, at 12 to 15 inches, is 8 or 9 years old. California sets no minimum size on the species, so nothing in the regulations reflects that. It is the same arithmetic that shows up on black croaker, a species that takes 20 years to reach 14 inches with no size limit either. A bay full of numerous small fish can still be a bay full of old ones.

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.