Fish Community Ecology in an Altered River Delta: Spatial Patterns in Species Composition, Life History Strategies, and Biomass
Estuaries Vol. 28, No. 5, p. 776–785 October 2005 Fish Community Ecology in an Altered River Delta: Spatial Patterns in Species Composition, Life History Strategies, and Biomass MATTHEW L. NOBRIGA1,*, FREDERICK FEYRER1,RANDALL D. BAXTER2, and MICHAEL CHOTKOWSKI3 1 California Department of Water Resources, Ecological Studies Branch, 3251 S Street, Sacramento, California 95816 2 California Department of Fish and Game, Central Valley Bay-Delta Branch, 4001 North Wilson Way, Stockton, California 95205 3 U.S. Bureau of Reclamation, 2800 Cottage Way, Sacramento, California 95825 ABSTRACT: We sampled nearshore fishes in the Sacramento-San Joaquin Delta, California, United States, during 2001 and 2003 with beach seines and gill nets. We addressed three questions. How and why did fish assemblages vary, and what local habitat features best explained the variation? Did spatial variation in assemblages reflect greater success of particular life history strategies? Did fish biomass vary among years or across habitats? Nonmetric multidimensional scaling showed that habitat variables had more influence on fish assemblages than temporal variables. Results from both gear types indicated fish assemblages varied between Sacramento and San Joaquin River sampling sites. Results from gill net sampling were less pronounced than those from beach seine sampling. The Sacramento and San Joaquin river sites differed most notably in terms of water clarity and abundance of submerged aquatic vegetation (SAV), suggesting a link between these habitat characteristics and
[Show full text]