Smelt’s habitat in river, delta focus of environmental suit

A tiny silver fish few people in the Bay Area have heard of could be a new symbol of the state’s continuing battle over water resources.

San Francisco Baykeeper sued the Biden administration Thursday to list the local population of longfin smelt as an endangered species. The environmental group’s legal action comes nine years after the federal government first declared that the fish warranted that status.

Once an important source of food for marine mammals, birds and chinook salmon, the local population of the longfin smelt has dropped by 99.9% since the 1980s. Scientists and environmentalists say that reduction is a direct result of too much water from the Sacramento-San Joaquin river system being diverted to farms and other water users rather than flowing through the bay to the Pacific. If the fish were to be protected

as an endangered species, that would likely have to change.

“The longfin smelt is an avatar of sorts for a big range of sensitive species like salmon, delta smelt and sturgeon, and a lot of other species that are really on the brink of extinction themselves,” Ben Eichenberg, staff attorney for San Francisco Baykeeper. “The federal government and the state of California both have a responsibility for the extinction of the species that’s happening in the bay right now.”

The U.S. Fish and Wildlife Service, which is responsible for protecting endangered species, declined to comment because of the pending litigation.

Listing the longfin smelt, the lessfamous cousin of the delta smelt, as an endangered species would require the federal government to issue what’s called a biological opinion that could include water requirements for its habitat. That’s a politically thorny proposition, especially at the beginning of another drought, when water allotments to farms have already been cut.

Fish and farmers are often pitted against each other for the state’s water resources. At a Bakersfield news conference last year, former President Donald Trump blamed protections of “certain little tiny fish” — referring to the endangered delta smelt — for the state’s water problems.

He went on to announce that he would allow more water from the SacramentoSan Joaquin river system to go to farms.

Longfin smelt (Spirinchus thaleichthys), a 3to 4inch silvery fish named for its largerthanaverage pectoral fin, has a range from San Francisco Bay to Alaska, but it’s the local population that the state listed as threatened back in 2009.

While there are five other species native to San Francisco Bay that already have federal endangered species status — delta smelt, springand winterrun chinook salmon, steelhead trout and green sturgeon — longfin smelt has the most direct relationship to the bay’s water flow, said Jon Rosenfield, lead scientist at San Francisco Baykeeper.

“The volume of flow that makes it out of the delta from December to May or June is very strongly correlated over decades and decades with longfin smelt abundance,” Rosenfield said.

The fish requires freshwater when it spawns in winter and early spring in the delta or local rivers, said researcher Levi Lewis of UC Davis, who studies the species, and during years when less water comes through, the population drops.

Lewis and his colleagues have collected them for study in the brackish waters of Alviso Marsh in the southern part of the bay.

The California Department of Fish and Wildlife monitors the bay’s population of longfin smelt by sending a boat to 100 locations from September to December and pulling a net to see how many it catches. After getting a monthly average, it creates an index value that it can compare to previous years.

Historically, the department would find hundreds of longfin smelt in a single tow of their sampling net, whereas today it may take more than 100 trawls of the same net to catch a single longfin, Rosenfield said. The index numbers were in the tens of thousands in the early 1980s, dropping to the single digits in 2014, during the most recent drought, and have since gone back to double digits.

Rosenfield and San Francisco Baykeeper, among other organizations, have been petitioning the federal government to give endangered status to the San Francisco Baydelta population of longfin smelt since 1992. The U.S. Fish & Wildlife Service agreed that it warranted being listed as endangered in 2012, but it said it was “precluded,” meaning it had to wait in line behind other species. That message has repeated each year since.

While the longfin smelt may not be well known among locals, losing it would mean losing part of what makes the estuary special, Lewis said.

“We’re systematically eliminating elements of California’s natural heritage that made it unique,” he said. “The loss of these species is really the loss of California.”

James Ervin / UC Davis San Francisco Baykeeper wants longfin smelt listed as an endangered species.

James Ervin / UC Davis These longfin smelt were collected for study at Alviso Marsh in the South Bay. The smelt’s numbers in Northern California have plummeted since the 1980s.