Once the most abundant fish population in the San Francisco Bay-Delta, the state says the 4-to-6-inch estuarine fish are at a record low for the first time in 40 years, and the species is headed toward extinction. As a result, officials have declared it a candidate for the Endangered Species Act.
Although this move will not impose any new restrictions, state law still makes permits mandatory for anyone taking the fish. The fish is joining another 200-plus species across the country that have been deemed in danger, but are in line behind other priority listings.
Reduced freshwater outflow and ammonium contamination are preventing reproduction, according to the FWS. An increased population of the non-native overbite clam is a new competitor for the longfin smelt's plankton diet, the agency concluded.
The Bay-Delta distinct population segment (DPS) is one of at least 20 populations of longfin smelt found in estuaries, rivers, and lakes from Alaska to California. The Bay-Delta DPS is found in the San Francisco Bay-Delta, which includes Suisun Marsh and San Pablo Bay. The longfin smelt lives in open water, and can be distinguished from other smelts mainly by its long pectoral fin.