The white sturgeon, once one of the most numerous, popular and tasty gamefish in the Delta, has seen its numbers drop so precipitously that it may need to be listed as a threatened species, a new report says.
Until the 1990s, the population of legally harvestable white sturgeon in the rivers of the Sacramento-San Joaquin Delta was estimated at about 150,000, according to the report from the California Department of Fish and Wildlife. A 2020-21 survey showed their numbers had shrunk to 30,000 for fish in the 40- to 60-inch size range. Then came an algae bloom that is believed to have killed thousands more white sturgeon.
The official estimate is now 6,447 of the larger fish. When a wider range of sizes is included – sturgeon measuring 10 to 87 inches – there are about 19,000 in the Delta, researchers said.
Last June, the California Fish and Game Commission determined that listing the white sturgeon as threatened under the state’s Endangered Species Act “may be warranted.”
In February, four Bay Area environmental groups sued the Trump administration, alleging the U.S. Fish and Wildlife Service and the Secretary of the U.S. Department of the Interior failed to deliver a legally required initial determination as to whether the white sturgeon should be listed as a threatened species.
The white sturgeon is native to Central Valley rivers and Bay Area estuaries, equally at home in either fresh or salt water. It can grow up to 20 feet long, with a life span of more than 100 years. It doesn’t spawn until it’s 14 to 19 years old, and its offspring need the spring river outflows to survive.
White sturgeon are prized for their firm white flesh, but because of their shrinking numbers, they are no longer candidates for the dinner plate. They’ve been a recreational catch-and-release fish since August 2024, but even that designation may come to an end. The California Fish and Game Commission is scheduled to take up the issue at a meeting next month.
The algae bloom from the summer of 2022 is the latest catastrophe to strike the white sturgeon. The CDFW report also blames the shrinking population of the fish on poaching, past sportfishing harvests and the poor condition of the rivers in the Delta. One of the most prominent, the San Joaquin River, flows through Stockton and the San Joaquin Valley.
The Fish and Wildlife Department said it is using a new protocol for its sturgeon count. The latest survey establishes a new baseline, and multiple years of study will be needed to confirm the findings.
Surveys take place in the spring and fall along the Sacramento River from San Pablo Bay to Rio Vista.
Using a survey method based on one used in Oregon and Washington, workers unspool fishing lines with multiple baited hooks. White sturgeon caught on the hooks are then measured, tagged and set free. Months later, the number of fish caught with tags is compared to the number that is untagged in order to estimate the overall population size.
While the 2024 season represents the most rigorous survey of white sturgeon in California in many years, CDFW researchers say the numbers in the latest study are preliminary and based on the first year of a pilot study. The department secured funding through 2026 to implement
and refine the surveys, however, additional funding will be needed for a long-term monitoring program, officials say.
Want more? Sign up to get Stocktonia delivered to your inbox three days a week.