Stockton Fish and Wildlife Office is involved in an ongoing project to provide preliminary field information to evaluate salvage facility efficiency at the State Water Project (SWP) and pre-screen loss at Clifton Court Forebay (CCF), a reservoir north of Tracy, Calif.  The project is led by Stockton FWO in collaboration with the U.C. Davis Fish Conservation & Culture Laboratory, Tracy, and the California Department of Fish & Game, Stockton.

Cultured delta smelt were used in 2008 to develop the calcein marking method and to obtain preliminary estimates of entrainment loss for juvenile delta smelt through the Skinner Fish Facility. In addition, two groups of juvenile delta smelt were released in Clifton Court Forebay in spring 2008. All three juvenile mark-recapture tests were successfully completed in 2008.  These results showed significant decrease in fish recaptures at the Skinner Fish Facility with increasing distance from the release site.  Control fish held at ambient temperature experienced very high mortality when daily maximum temperatures exceeded 25^oC, suggesting concomitant reduced survival for both released fish and co-occurring wild delta smelt in CCF.

The next phase of this project involves mass-marking of adult and juvenile delta smelt in winter-spring 2009