Biological and chemical responses in a temporarily open/closed estuary to variable freshwater inputs
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In coastal lagoons with occasional connection to oceans, variations in physicochemical conditions and biological responses can be pronounced. To examine the influence of variable rainfall and tidal flushing, we measured, over a 4-year period, salinity, temperature and dissolved oxygen, and fish abundances, in Devereux Slough, a coastal lagoon occasionally connected to the Pacific Ocean along the California coast. We test the hypotheses that salinity is the primary influence on fish composition, and that fish density is affected by freshwater discharge and by berm breaches. During our sampled years, annual rainfall varied from 188 to 971 mm, and the sand berm separating the Slough from the ocean breached in each year except 2007, a drought period. Average yearly salinity ranged from 7.7 to 37.1 ppt. Hypoxic conditions in the near-bottom water were common each year. The best predictor of the fish composition was salinity, and an indirect correlation with fresh water discharge was responsible for much of the temporal variation in the fish assemblage. The interaction between salinity, state of the estuary mouth (open vs. closed), and precipitation significantly predicted densities of Fundulus parvipinnis (Girard 1984).
KeywordsSalinity Coastal lagoon Physicochemical conditions Fish Resource management
This research was supported by the NSF-funded Santa Barbara Coastal Long-term Ecological Research Program (Awards OCE-9982105 and OCE-0620276), the Coastal Fund, the UC Natural Reserve System and volunteer service. We thank Kevin Lafferty and Cristina Sandoval of Coal Oil Point Reserve for logistical support and advice, Tara Longwell, Darryl Yin, Michael Massoud, Alex Hurst and Kevin Le for field assistance, and Blair Goodridge and Scott Coombs with hydrological data.
- Barnes, R. S. K., 1980. Coastal Lagoons: The Natural History of a Neglected Habitat. Cambridge University Press, Cambridge, U.K.Google Scholar
- Brooks, A. J., 1999. Factors influencing the structure of an estuarine fish community: the role of interspecific competition. Ph.D. Thesis. University of California, Santa Barbara.Google Scholar
- Clarke, K. R. & R. M. Warwick, 1994. Change in Marine Communities: An Approach to Statistical Analysis and Interpretation. Natural Environment Research Council, Plymouth Marine Laboratory, Plymouth.Google Scholar
- Collins, J. N., E. D. Stein, M. Sutula, R. Clark, A. E. Fetscher, L. Grenier, C. Grosso & A. Wiskind, 2008. California Rapid Assessment Method (CRAM) for Wetlands and Riparian Areas. www.cramwetlands.org.
- Davis, F. W., D. Theobald, R. Harrington & A. Parikh, 1990. Campus Wetlands Management Plan, Part 2, Technical Report on Hydrology, Water Quality and Sedimentation of West and Storke Campus Wetlands. University of California, Santa Barbara.Google Scholar
- Day, J. H., 1981. Summaries of current knowledge on 43 estuaries. Estuarine Ecology with Particular Reference to Southern Africa. A.A. Balkema, Cape Town: 259–341.Google Scholar
- Everett, J. D., M. Baird, & I. Suthers, 2007. Nutrient and plankton dynamics in an intermittently closed/open lagoon, Smiths Lake, south-eastern Australia: an ecological model. Estuarine, Coastal and Shelf Science 72: 690–702.Google Scholar
- Ferren, W. R., Jr., D. Capralis & D. Hickson, 1987. Campus wetlands management plan, Part I, Technical report on the botanical resources of West and Storke Campuses. Herbarium Report No. 12, University of California, Santa Barbara.Google Scholar
- Goodman, D., 2008. Effective estuarine management: a case study of a California estuary and its ecological and political characteristics. Ph.D. Thesis. University of California, Santa Barbara. 358 pp.Google Scholar
- Kuris, A. M., R. F. Hechinger, J. C. Shaw1, K. L. Whitney, L. Aguirre-Macedo, C. A. Boch, A. P. Dobson, E. J. Dunham4, B. L. Fredensborg, T. C. Huspeni6, J. Lorda, L. Mababa, F. T. Mancini, A. B. Mora, M. Pickering, N. L. Talhouk, M. E. Torchin & K. D. Lafferty, 2008. Ecosystem energetic implications of parasite and free-living biomass in three estuaries. Nature 454: 515–518.Google Scholar
- Kjerfve, B. (ed.), 1994. Coastal Lagoon Processes. Elsevier Oceanographic Series 60. Elsevier, Amsterdam. 577 pp.Google Scholar
- Lafferty, K. D., 2008. Camp Pendleton Tidewater Goby monitoring project report (2008 update). U.S. Geological Survey Open File Report.Google Scholar
- Magurran, A. E., 2006. Measuring Biological Diversity. Blackwell Science, Malden, MA.Google Scholar
- McGinnis, S. M. & D. Alcorn, 2006. Field Guide to Freshwater Fishes of California. University of California Press.Google Scholar
- Middaugh, D. P., 1988. Salinity tolerance of young topsmelt, Atherinops affinis, cultured in the laboratory. California Fish and Game 74: 232–235.Google Scholar
- Swift, C. C., J. L. Nelson, C. Maslow & T. Stein, 1989. Biology and distribution of the tidewater goby, Eucyclogobius newberryi (Pisces: Gobiidae) of California. Natural History Museum of Los Angeles, Scientific Contribution 404: 1–19.Google Scholar
- USACE, 2002. HEC-RAS river analysis system, user’s manual, US Army Corps of Engineers, Hydrologic Engineering Center, Davis.Google Scholar
- United States Fish and Wildlife Service, 2006. Draft Recovery Plan for the Endangered (Eucyclogobius newberryi). Ventura, CA.Google Scholar
- Whitfield, A. K., A. W. Paterson, A. H. Bok & H. M. Kok, 1994. A comparison of the ichthyofaunas in two permanently open eastern Cape estuaries. South African Journal of Zoology 29:175-1855-185.Google Scholar