Fish Assemblage and Diet Composition Across a Vegetation Gradient in a Restoring Tidal Freshwater Wetland

The Sacramento-San Joaquin Delta of the San Francisco Estuary is a highly manipulated ecosystem with structural impacts including levees and water diversions that have occurred over the last century. Several restoration efforts are underway, including at Liberty Island, a breached levee island once used for agriculture thought to provide good habitat for fish, particularly species of concern (i.e. Delta smelt and Chinook salmon). We are investigating the relationship between fish assemblages, life histories and diet across the vegetation colonization gradient. Sampling occurred at six sites on Liberty Island from March 28 – April 2, 2010. We caught 17 species using gill nets, fyke nets and purse seines across vegetation gradients. Only five of the 17 species caught were native to California. Notably, ten Delta smelt were caught, which is a federally listed endangered species. The most abundant species caught were the non-native inland silversides. Results indicate that inland silversides and Delta smelt exhibit 12.24% diet similarity, but not statistically significant. Catfish and Carp were the primary demersal feeding species caught and had 11.68% diet similarity. Understanding fish habitat use and food resources will allow researchers to gain insight about ecosystem dynamics and assess the habitat quality within this restoring wetland.