Swimming toward extinction: Longfin smelt could be added to endangered species list

The U.S. Fish and Wildlife Service has proposed listing San Francisco Bay’s longfin smelt as an endangered species, the latest sign that drought and climate change are having an impact on the Bay-Delta ecosystem.

The proposal to give additional protection to the Bay-Delta longfin smelt was made on Oct. 7 and opens a public comment period that will close on Dec. 6, according to the Federal Register.

Three lawsuits were filed by Bay Area conservation groups including San Francisco Baykeeper and the Center for Biological Diversity, seeking a listing under the Endangered Species Act.

“Our local longfin smelt population is particularly sensitive to changes in the volume of fresh water flowing into San Francisco Bay,” said Jon Rosenfield, Ph.D., senior scientist for San Francisco Baykeeper. “The longfin smelt’s catastrophic decline is yet another sign that water diversions from the rivers that feed the Bay are unsustainable.”

The recommendation to include the smelt under the Endangered Species Act follows a finding in 2012 that determined the local fish were a distinct population. The wildlife service said additional genetic evidence has since supported that finding, making the fish a so-called “distinct population segment.”

“The longfin smelt’s catastrophic decline is yet another sign that water diversions from the rivers that feed the Bay are unsustainable.”

Jon Rosenfield, Ph.D., San Francisco Baykeeper

“Because of its limited swimming capabilities and because of the great distances between the San Francisco Bay-Delta and known breeding populations to the north, we conclude that the San Francisco Bay-Delta population is markedly separated from other longfin smelt populations,” the wildlife service wrote in its assessment.

The recommendation also noted, “designation of critical habitat for the Bay-Delta longfin smelt is not determinable at this time,” so it is unclear how the rule could affect future projects.

Comments may be submitted online. By mail, send comments to Public Comments Processing, Attn: FWS-R8-ES-2022-0082, U.S. Fish and Wildlife Service, MS: PRB/3W, 5275 Leesburg Pike, Falls Church, VA 22041-3803.