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US Fish & Wildlife Service FieldNotes
STOCKTON FWO: Delta Smelt Pre-Screen Loss and Salvage Efficiency at the State Water Project
Region 8, February 25, 2009
Release of marked juvenile delta smelt in Clifton Court Forebay (photo: USFWS)
Release of marked juvenile delta smelt in Clifton Court Forebay (photo: USFWS) - Photo Credit: n/a

by Gonzalo Castillo, Stockton FWO

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 25oC, 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



Contact Info: Yvette Leatherman, (209) 946-6400 x301, yvette_leatherman@fws.gov