800px-Hypomesus_transpacificus.jpgThe U.S. Fish and Wildlife Service announced today that biological evidence proves that delta smelt warrants being upgraded from a “threatened” to an “endangered” species.

However, the agency is not going to begin the process of listing the species as endangered because upgrading it would not increase the protections that are already in place, U.S. Fish and Wildlife Service spokesman Steve Martarano said.

Because delta smelt is listed as a threatened species, agencies already need a permit from the Fish and Wildlife Service for any activities that will result in the take of any delta smelt, Martarano said.

Delta smelt are only found in the San Francisco Bay and Sacramento-San Joaquin Delta Estuary in Contra Costa, Sacramento, San Joaquin, Solano and Yolo counties.

They were once one of the most common fish in the Delta, but their population has decreased drastically, and in 2003, they were listed as a threatened species under the Endangered Species Act.

Critical habitat was designated for the species in 2004. However, the most recent estimate of the delta smelt population is the lowest ever recorded – almost one tenth of the population in 2003.

A 2005 population viability analysis calculated that there was a 50 percent likelihood that the species could become extinct within the next 20 years, according to the Fish and Wildlife Service.

The primary threats to the species include getting caught in the pumps of state and federal water export facilities, summer and fall increases in salinity and clarity, and competition with introduced species, according to the agency.

Delta smelt are also considered an indicator species because as its population has declined, so has the population of all other species living in the Delta, Martarano said.

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