Prehistoric giant living in San Francisco Bay sees sharp decline

Yahoo

12-07-2025

SAN FRANCISCO (KRON) — A prehistoric fish that can grow up to 20 feet in length and is still found in the San Francisco Bay is seeing a steep decline in population across California, according to a new report released this week from the California Department of Fish and Wildlife.
The number of white sturgeons, the largest freshwater fish in the United States, has been monitored in California since 1954. Wildlife officials said population estimates from the 1990s and earlier reached approximately 150,000 or more that were within the legal size to harvest. A five-year survey average between 2016-2021 showed an estimated population of 30,000.
Preliminary results from the new 2024 survey released Wednesday estimated that only 6,447 white sturgeons of harvest size, currently 40 to 60 inches in length, remain in the California population.
White sturgeons can live for more than 100 years and spawn for the first time after reaching 14 to 19 years old. Following the first spawn, the sturgeons continue to spawn every two to five years.
A number of factors have impacted white sturgeon numbers in California, including loss of habitat due to dams, degraded river flows from a highly altered water system, historical sport fishing harvests, poaching and mortality due to toxic algal blooms. A Harmful Algal Bloom event in the summer of 2022 is believed to have killed thousands of sturgeons, according to CDFW.
The 2024 survey was conducted in the spring and fall between San Pablo Bay and Rio Vista. Wildlife officials said the study design was peer-reviewed and is 'the most robust and comprehensive white sturgeon population monitoring survey ever conducted in California.'
In June 2024, white sturgeons were added to a list of candidate species for protection under the California Endangered Species Act (CESA). During the review process, white sturgeon receive full CESA protection from harm.
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