Acipenser Transmontanus (White Sturgeon): Size, Rules

Acipenser transmontanus is the white sturgeon, a Pacific coast species that lives at sea and runs up big rivers to spawn (FishBase). Wikipedia gives a maximum length of 6.1 m (20 ft) and a heaviest authenticated weight of 630 kg (1,390 lb); FishBase lists a maximum published weight of 816 kg and a reported age of 104 years, which Wikipedia treats as unconfirmed. A recent California fish measured 2.8 m and 210 kg (Wikipedia).

How to recognise one (Wikipedia):

• No scales, but rows of bony plates (scutes), with two rows of 4 to 8 plates between the vent and the anal fin
• Barbels in front of the mouth, closer to the tip of the snout than to the mouth
• Colour: grey to brownish above, paler below
• About 45 rays in the dorsal fin

Not sure it is a sturgeon? Scan it with the FishLens app, or compare it with another river giant on our arapaima page.

White sturgeon live along the Pacific coast from the Gulf of Alaska to Monterey, California, with reports from northern Baja California (Wikipedia; FishBase). In practice that means Alaska, Washington, Oregon and California on the coast, and Idaho and Montana inland: FishBase lists a landlocked population in the Columbia drainage in Montana, and the US Fish and Wildlife Service describes the Kootenai River population in Idaho, Montana and British Columbia. Wikipedia also lists landlocked fish in the Fraser, Columbia and Snake rivers and possibly Lake Shasta. The Kootenai population is one of 18 landlocked populations in western North America (US FWS).

Still widespread, but declining and slow to recover. The IUCN rates the species Vulnerable (assessed 15 September 2020, via FishBase), and the American Fisheries Society lists it as Endangered (Wikipedia). The clearest warning is the Kootenai River population, listed as Endangered in 1994: the US Fish and Wildlife Service says it fell from about 7,000 fish in the late 1970s to 760 in 2000, that in 14 years of monitoring only one hatching embryo was found, and that fewer than 50 adults may remain by 2030.

Slow breeding is why. Females mature at about 9 years in the Sacramento-San Joaquin system and spawn only every 2 to 4 years (Wikipedia); FishBase gives intervals of 4 years in younger females up to 10 to 11 years in older ones.

It depends on the species and the state. For Atlantic, shortnose and Gulf sturgeon on the East and Gulf coasts, NOAA Fisheries is clear: it is illegal to fish for, catch or keep them, and one caught by accident must be released with care. White sturgeon are different: some fishing is allowed under state rules.

• California: the California Department of Fish and Wildlife runs a sturgeon report card, and its page says the white sturgeon season closed on 30 June and reopens on 1 October (checked 25 September 2026). Wikipedia notes that selling wild sturgeon is illegal in California; legal caviar there comes from farms.
• Columbia River Basin: catch-and-release fishing is allowed (Wikipedia)
• Kootenai River: the population is federally Endangered (US FWS)

Rules change often, so read the current regulations for the exact water before you fish, and release any sturgeon you are not sure you may keep.

Not towards people. None of the sources on this page describe white sturgeon attacking anyone. They are bottom feeders: young fish under about 48 cm eat midge larvae and crustaceans, and larger fish mainly eat other fish (FishBase), including herring, salmon, smelt and anchovy along with bottom invertebrates (Wikipedia). The risk is to the fish: a 2 to 3 m sturgeon is easily injured if it is dragged onto a bank or lifted by the tail, so follow catch-and-release guidance and keep big fish in the water.