Another wildcard — this time in the form of the Bay-Delta smelt related to the Delta smelt — has been tossed into the high stakes California water game involving the water flowing through the Delta.
The United States Fish & Wildlife Service has officially listed the longfin smelt as endangered.
The longfin smelt is a fish ranging from 3.5 to 4.3 inches in length, with a lifespan of about 2 to 3 years.
It inhabits bays and estuaries along the Pacific Coast from Northern California to Alaska.
In the San Francisco Bay-Delta region, the species is restricted to the San Francisco Bay estuary and adjacent areas of the Pacific Ocean.
The endangered Delta smelt — listed so a number of years ago by the state — is a 3-inch fish found only in the Sacramento-San Joaquin Delta.
It is considered especially sensitive because it lives just one year, has a limited diet and exists primarily in brackish waters — a mix of river-fed fresh and salty ocean water that is typically found in coastal estuaries).
The Delta Smelt’s tendency to swim near the pumps at Clifton Court Forebay northwest of Tracy that lifts water into the California Aqueduct and Delta-Mendota Canal has often forced water managers to curtail the amount of water flowing south.
It is one of the reasons why large southwest San Joaquin Valley agricultural interest and urban water users in Southern California are pushing for the $20 billion Tunnel project
It is unclear if the latest listing under the federal Endangered Species Act of the longfin Bay-Delta Smelt will impact the tunnel project that would divert water out of the Sacramento River before it reaches the Delta.
That said, the water diversion — coupled with this week’s federal order — could ultimately impact how water is managed to protect the Bay-Delta smelt in addition to what is already in place for the Delta smelt.
If that happens and the tunnel takes a large amount of water out of the equation of what is now flowing into the San Francios Bay estuary via the Delta and makes it less conducive for the Bay-Delta smelt, it could trigger demands for replacement water.
“While we disagree with the conclusions supporting this particular listing decision, it is clear that the longfin smelt, like many species inhabiting the Delta, are under significant duress and are in need of active management,” said Federico Barajas, Executive Director of the San Luis & Delta-Mendota Water Authority.
“The listing of the longfin smelt under the federal ESA, closely following a candidate listing of white sturgeon under the California ESA, continues to point to a degraded ecosystem resulting from a number of stressors, including invasive species, habitat degradation, predation, and a changing climate, that without significant changes is likely to lead to further species being listed.”
The water authority relies on Central Valley Project water that enters the Delta from the Sacramento River to support farming on the Westside of the San Joaquin Valley in the general area centered around Los Banos.
“The last 30 years has demonstrated that a species-by-species approach that is primarily reliant on managing water project operations is unlikely to restore the Delta ecosystem to one that provides the necessary biological functions to support species recovery,” Barajas noted.
“We must move towards an ecosystem-based approach to improve the underlying conditions that enable food production, restore habitat function — including functional flows, and reduce the impacts of predators and invasive species. Any other pathway simply doubles down on failed policies that have not resulted in significant species recovery but have caused tremendous harm to communities, farms, and other species in the San Joaquin Valley.”
Longfin smelt were once abundant in the San Francisco Bay estuary, but populations have declined more than 99% from 1980s levels according to Baykeeper, an Oakland-based nonprofit dedicated to defending the health of San Francisco Bay. The group attributes the fish’s decline to diversion of Central Valley tributary rivers that slash annual freshwater flow into the bay.
This overuse of freshwater resources, which are mostly diverted for large-scale agricultural purposes, causes perpetual drought-like conditions for longfin smelt and other native fish in the bay.
The ruling is a response to a 2007 petition and years of legal action by environmental organizations, including a 2024 lawsuit filed by Baykeeper.
The listing means there are now six fish species native to San Francsico Bay that are considered endangered.
