The nation’s largest freshwater fish could be added to California’s endangered species list

The largest freshwater fish in North America, once abundant in the major rivers of California and San Francisco Bay, has declined in numbers to a point where government officials will consider whether to protect the fish as a threatened species among the Endangered State Species Act.

The white sturgeon can grow to more than 10 feet in length and spends much of its life in San Francisco Bay, swimming upstream in rivers to spawn. It is believed that some white sturgeon can live up to a century.

Recent population estimates indicate that the fish are struggling to survive despite many pressures.

The California Fish and Game Commission voted last week to accept a petition calling for the white sturgeon to be placed on the state’s endangered species list. The commission’s decision that protections may be warranted sets off an investigation by state fisheries experts, who are expected to present a report in about a year. The committee will then decide whether the white sturgeon will be declared an endangered species.

Supporters of imposing protections say the fish are threatened by water diversions that reduce river flows, harmful algal blooms that can cause fish kills, and overfishing by recreational fishermen. They say the fish are particularly vulnerable because they rarely spawn – only in wet years with high river flows.

Due to their gigantic size, white sturgeon species are an exception among fish species in the Sacramento-San Joaquin River Delta estuary.

“They’re even bigger than a mountain lion,” Jon Rosenfield, scientific director of the San Francisco Baykeeper group, said in a speech to the committee. “This is an ancient lineage. The white sturgeon split from other sturgeon species and paddlefish about 46 million years ago. In that time, they have weathered everything Mother Nature threw at them, which makes it even more poignant that they are struggling to keep up with us. to survive.”

San Francisco Baykeeper and other groups, including California Sportfishing Protection Alliance and Restore the Delta, filed a petition last year calling for the species to be listed as endangered.

If the state ultimately declares the white sturgeon an endangered species, the protections could further complicate debates over water management and ecological protection in the delta, the central hub of the state’s water system, where pumps fill aqueducts that feed farms and towns across Supplying California.

Advocates for protecting the fish argue that the state’s plans for infrastructure projects such as the Sites Reservoir and a proposed water tunnel in the delta would further endanger the species.

“Their population is declining and there is an imminent threat of further degrading their habitat by diverting high river flows,” Rosenfield told the committee.

He and other conservationists said stresses on the species are likely to worsen due to climate change.

“They’re in bad shape. They’ve been deteriorating for a while,” Rosenfield said. “So they need protection under the Endangered Species Act.”

Representatives of water agencies urged the commission not to accept the petition. Jennifer Pierre, general manager of the State Water Contractors, and Federico Barajas of the San Luis & Delta-Mendota Water Authority said in a letter to the commission that the petition is flawed and incomplete, lacks evidence and is “not based on the best available science.”

They also said the petition ignores regulations already in place that provide protections for the white sturgeon.

Pierre and Barajas, who together represent agencies that provide water to approximately 29 million people and 1.9 million acres of farmland, argued that claims that the species would be harmed by the Delta Conveyance Project and the Sites Reservoir are unfounded, and that water diversions for those projects would be subject to state and federal permitting and environmental restrictions.

“The current regulatory framework is protective,” Pierre and Barajas wrote, adding that available data show that population size has remained stable over the past fourteen years.

Others who spoke against the petition run recreational fishing boat businesses.

The commission’s decision means white sturgeon will be temporarily protected while the state considers the petition. Fishing for sturgeon was until recently allowed based on fish size and other restrictions, but fishing will now be prohibited while the state review is underway.

Other fish species currently listed by the state or federal government as threatened or endangered in the Bay-Delta River Basin include longfin smelt, delta smelt, spring Chinook salmon, winter Chinook salmon, brown trout and the separate population of green sturgeon.

Environmental regulations intended to protect fish species sometimes lead to restrictions on pumping at the state and federal facilities that draw water from the delta.

Sturgeons are distinguished by their shark-like, torpedo-shaped bodies and rows of bony plates called scales in their skin. They are called living fossils because their ancestors swam in rivers and estuaries 200 million years ago, and they survived the mass extinction that wiped out the dinosaurs 66 million years ago.

Because of their long lives, the giant fish are also called “the redwoods of the bay.”

In the late 19th century, California had a commercial fishery for white sturgeon, but the population quickly collapsed and the fishery was closed in the early 20th century.

In 1954, the state opened a recreational fishery for white sturgeon.

Boaters have continued to catch the fish legally under state regulations, which until recently allowed a limited catch of fish 40 to 60 inches long.

Others have turned to illegal fishing for the prized sturgeon roe, selling the caviar for profit. In recent years, some poaching investigations by state officials have led to arrests.

According to state estimates, the white sturgeon population of a size that can be legally caught has declined from between 150,000 and 200,000 in the 1980s to the most recent five-year average of 33,000 fish.

However, that estimate does not take into account losses during an algae bloom in San Francisco Bay in 2022, when white sturgeon were among the large numbers of fish that died.

California Department of Fish and Wildlife biologists will assess the status of the species. The process gives officials one year, but they can request a six-month extension to complete their analysis.

The state’s population estimates were calculated using the standard method of catching fish, which involves attaching dime-sized metal plates to the base of their dorsal fin and then releasing them. In recent years, those who catch the fish have turned in the tags for cash rewards, allowing biologists to make estimates of how many fish are in the estuary.

“There is a continued long-term decline,” said John Kelly, the statewide sturgeon coordinator for the Department of Fish and Wildlife. “They face a number of challenges.”

The evaluation will involve analyzing available data from agencies, academic researchers and other sources, Kelly said, and will also undergo a peer-review process.

White sturgeon can venture into the ocean from San Francisco Bay, but they are believed to spend most of their lives in the estuary. There are other populations of the species in the Pacific Northwest, including in the Columbia River and the Fraser River in British Columbia.

Rosenfield said one way to help California’s white sturgeon would be to allow only catch-and-release fishing, which is popular on the Fraser River.

“It’s been very, very successful. The fish are much bigger than our fish because they live longer,” he said.

“People can still enjoy fishing for these fish,” he said. “They can enjoy them without killing them.”