California Department of Fish and Wildlife

Salinity effects on native and introduced SAV of Suisun Bay and the Delta

photo comparison of Egeria densa and Stuckenia pectinata

Photo comparison of Egeria densa (left) and Stuckenia pectinata (right)
Photo by K. Boyer, San Francisco State University, Romberg Tiburon Center for Environmental Studies

Location: Sacramento–San Joaquin Delta and Suisun Bay

Total Project Cost: $412,405 (Ecosystem Restoration Program)

Partners: CDFW, San Francisco State University, Romberg Tiburon Center for Environmental Studies

Project Summary: This project evaluates the role of increased salinity on native (dominated by Stuckenia pectinata) versus introduced (Egeria densa) submerged aquatic vegetation (SAV) beds in an effort to predict how native Stuckenia pectinata beds might contribute to restoration of native communities and functions in the Sacramento-San Joaquin Delta and Suisun Bay.

This project will determine ecological characteristics of shallow water habitat likely to support native species, and test the hypothesis that manipulating salinity can help to control invasive species. Specifically the project will address the uncertainty of the effects of increased salinity in Suisun Bay and the Delta, possible through multiple mechanisms, on conservation and restoration of native SAV and associated animal assemblages. Several special status fish species identified in the Multi-Species Conservation Strategy, including Delta smelt and Chinook salmon, may benefit from the relatively open canopies and food resources of native Stuckenia beds, without being subject to predation in the dark recesses of non-native Egeria beds. This research will permit prediction of future distribution of these native Stuckenia beds under increased salinity scenarios, and thus the habitat it provides to native fishes.

The results of this project can be used to inform management decisions that will influence salinity regimes and the resultant natural aquatic habitats and associated native species. In addition, this project will address the goal statement of reducing habitat for non-native species and their negative ecological effects, by assessing salinity conditions that in the future Delta are likely support native SAV instead of invasive Egeria and its promotion of predation on native special status fish species.

The project is a companion to two recently funded projects: a survey of their distribution Stuckenia beds (funded by National Oceanic and Atmospheric Administration (NOAA)), and a study that will identify and enumerate invertebrates in Stuckenia beds (funded through the Delta Science Program).

This research is scheduled to be completed in 2015.