Is the Response of Estuarine Nekton to Freshwater Flow in the San Francisco Estuary Explained by Variation in Habitat Volume?
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Abundance of estuarine biota can vary with freshwater inflow through several mechanisms. One proposed mechanism is that the extent of physical habitat for an estuarine species increases with flow. We estimated the contribution of variation in habitat volume to the responses of eight species of estuarine nekton to changes in freshwater flow in the San Francisco Estuary. Resource selection functions for salinity and depth were developed for each species (and for five additional species) using five monitoring data sets. The TRIM3D hydrodynamic model was run for five steady flow scenarios to determine volume by salinity and depth, and resource selection functions were used as a weighting factor to calculate an index of total habitat for each species at each flow. The slopes of these habitat indices vs. flow were consistent with slopes of abundance vs. flow for only two of the species examined. Therefore, other mechanisms must underlie responses of abundance to flow for most species.
KeywordsFish Habitat Freshwater flow Resource selection function San Francisco Estuary
Funding for this study was provided by CALFED Bay-Delta Program Contract ERP-02-P19. We thank W. Bennett for helpful discussions. F. Feyrer and M. Weaver provided helpful comments on the manuscript.
- Bennett, W.A. 2005. Critical assessment of the delta smelt population in the San Francisco Estuary, California. San Francisco Estuary and Watershed Science 3(2): Art. 1. (Online Serial) http://repositories.cdlib.org/jmie/sfews/vol3/iss2/art1.
- Cloern, J.E. 1991. Annual variations in river flow and primary production in the South San Francisco Bay estuary (USA). In Estuaries and coasts: Spatial and temporal intercomparisons, eds. M. Elliott, and J.-P. Ducrotoy, 91–96. Fredensborg: Olsen and Olsen.Google Scholar
- Cloern, J.E., and F.H. Nichols. 1985. Temporal dynamics of an estuary: San Francisco Bay. Hydrobiologia. Dordrecht: Junk.Google Scholar
- Conomos, T.J. 1979. San Francisco Bay: The urbanized estuary. San Francisco: Pacific Division, American Association for the Advancement of Science.Google Scholar
- Dege, M., and L.R. Brown. 2004. Effect of outflow on spring and summertime distribution and abundance of larval and juvenile fishes in the upper San Francisco Estuary. In Early life history of fishes in the San Francisco Estuary and Watershed, eds. F. Feyrer, L.R. Brown, R.L. Brown and J.J. Orsi, 49–65. American Fisheries Society Symposium Vol. 39. Bethesda MD: American Fisheries Society.Google Scholar
- Emmett, R.L., S.L. Stone, S.A. Hinton, and M.E. Monaco. 1991. Distribution and abundance of fishes and invertebrates in west coast estuaries, volume II: Species life history summaries. NOAA/NOS Strategic Environmental Assessments Division.Google Scholar
- Gross, E.S., M.L. MacWilliams, and W. Kimmerer. 2006. Simulating periodic stratification in San Francisco Bay. Proceedings of the Ninth Estuarine and Coastal Modeling Conference, ASCE, pp. 155–175.Google Scholar
- Hollibaugh, J.T. 1996. San Francisco Bay: the ecosystem. Further investigations into the natural history of San Francisco Bay and delta with reference to the influence of man. San Francisco: American Association for the Advancement of Science.Google Scholar
- Kimmerer, W.J. 2004. Open water processes of the San Francisco Estuary: from physical forcing to biological responses. San Francisco Estuary and Watershed Science (Online Serial) 2: Issue 1, Article 1. http://repositories.cdlib.org/jmie/sfews/vol2/iss1/art1.
- Kimmerer, W.J., J.H. Cowan Jr., L.W. Miller, and K.A. Rose. 2000. Analysis of an estuarine striped bass population: Influence of density-dependent mortality between metamorphosis and recruitment. Canadian Journal of Fisheries and Aquatic Sciences 57: 478–486. doi: 10.1139/cjfas-57-2-478.CrossRefGoogle Scholar
- Manly, B.F.J., L.L. McDonald, D.L. Thomas, T.L. Mcdonald, and W.P. Erickson. 2002. Resource selection by animals: Statistical design and analysis for field studies. 2Dordrecht: Kluwer.Google Scholar
- Nixon, S.W., C.A. Oviatt, J. Frithsen, and B. Sullivan. 1986. Nutrients and the productivity of estuarine and coastal marine systems. Journal of the Limnological Society of South Africa 12: 43–71.Google Scholar
- Nobriga, M., T. Sommer, F. Feyrer, and K. Fleming. 2008. Long-term trends in summertime habitat suitability for delta smelt, Hypomesus transpacificus. San Francisco Estuary and Watershed Science 6: Issue 1 Article 1.Google Scholar
- Riley, G.A. 1937. The significance of the Mississippi River drainage for biological conditions in the northern Gulf of Mexico. Journal of Marine Research 1: 60–74.Google Scholar
- Skreslet, S. 1986. The role of freshwater outflow in coastal marine ecosystems, NATO ASI Series G ed. Berlin: Springer.Google Scholar
- Turner, J.L., and H.K. Chadwick. 1972. Distribution and abundance of young-of-the-year striped bass, Morone saxatilis, in relation to river flow in the Sacramento–San Joaquin estuary. Transactions of the American Fisheries Society 101: 442–452. doi: 10.1577/1548-8659(1972)101<442:DAAOYS>2.0.CO;2.CrossRefGoogle Scholar
- Venables, W.N., and B.N. Ripley. 2002. Modern applied statistics with S. 4New York: Springer.Google Scholar
- Wilber, D.H. 1994. The influence of Apalachicola River flows on blue crab, Callinectes sapidus, in north Florida. Fishery Bulletin 92: 180–188.Google Scholar