Evaluating short-term effects of omnivorous fish removal on water quality and zooplankton at a subtropical lake
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We evaluated a biomanipulation program to test for short-term changes in water quality (chlorophyll a, Secchi depth, total phosphorus) and macrozooplankton biomass following partial removal of omnivorous gizzard shad Dorosoma cepedianum. The removal occurred at a eutrophic subtropical lake, and responses were compared to an unmanipulated control lake using a before-after-control-impact paired series analysis. The removal reduced the biomass of large (>300 mm) gizzard shad by 75% over 2 years via a subsidized commercial gill net fishery. However, the total population biomass of gizzard shad was reduced by approximately 32% from an average pre-manipulation biomass of 224 kg ha−1 due to the size selectivity of the gear, which did not effectively capture small fish (<300 mm). No significant short-term changes in chlorophyll a concentration, Secchi depth, total phosphorus concentration or macrozooplankton biomass were detected following biomanipulation. The partial removal may have fallen short of the biomass reduction required to cause ecosystem responses. Our results suggest that moderate omnivore removals (i.e., <40% biomass reduction) will have little short-term benefits to these lakes, and future manipulations should use a less size-selective gear to achieve a larger total biomass reduction.
KeywordsGizzard shad Nutrient cycling Omnivory BACI analysis Water quality Subtropical lakes
Many thanks to B. Baker, C. Barrientos, G. Binion, A. Bunch, M. Bunch, J. Dotson, P. Hall, G. Kaufman, E. Thompson, and A. Watts for assistance with sample collection and taxonomic identification of zooplankton. Walt Godwin and Brian Sparks of the SJRWMD were helpful with planning logistics for field work and providing portions of the data set presented here. The authors are grateful to the SJRWMD staff and two anonymous reviewers for helpful comments on drafts of the manuscript. M. Catalano was supported by a University of Florida Alumni Doctoral Fellowship. The research presented here was funded in part by the St. John’s River Water Management District, Palatka, Florida.
- Allen, M. S., M. V. Hoyer & D. E. Canfield Jr., 2000. Factors related to gizzard shad and threadfin shad occurrence and abundance in Florida lakes. Journal of Fish Biology 57: 291–302.Google Scholar
- Benndorf, J., 1997. Possibilities and limits for controlling eutrophication by biomanipulation. International Review of Hydrobiology 80: 519–534.Google Scholar
- Catalano, M. J. & M. J. Allen, 2009. Assessing Effects of Gizzard Shad Removal on Gizzard Shad Population Dynamics in Florida Lakes. Final Report to the St. Johns River Water Management District: Contract #SI40613. University of Florida, Gainesville, FL.Google Scholar
- Cohen, J., 1988. Statistical Power Analysis for the Behavioral Sciences. Erlbaum Associates, Hillsdale, NJ.Google Scholar
- Drenner, R. W. & K. D. Hambright, 1999. Review: biomanipulation of fish assemblages as a lake restoration technique. Archiv für Hydrobiologie 146: 129–165.Google Scholar
- Elmore, J. L., B. C. Cowell & D. S. Vodopich, 1984. Biological communities of three subtropical Florida lakes of different trophic character. Archiv für Hydrobiologie 100: 455–478.Google Scholar
- FDEP, 2004. Standard Operating Procedures for Laboratory Activities. DEP-SOP-002/01, Tallahassee, FL.Google Scholar
- Hansson, L.-A., H. Annadotter, E. Bergman, S. F. Hamrin, E. Jeppesen, T. Kairesalo, E. Luokkanen, P.-A. Nilsson, M. Søndergaard & J. Strand, 1998. Biomanipulation as an application of food-chain theory: constraints, synthesis, and recommendations for temperate lakes. Ecosystems 1: 558–574.CrossRefGoogle Scholar
- Jeppesen, E., M. Sondergaard, N. Mazzeo, M. Meerhoff, C. C. Branco, V. Huszar & F. Scasso, 2005. Lake restoration and biomanipulation in temperate lakes: relevance for subtropical and tropical lakes. In Reddy, M. V. (ed.), Tropical Eutrophic Lakes: Their Restoration and Management. Science Publishers, Enfield, New Hampshire: 331–349.Google Scholar
- McCauley, E., 1984. The estimation of abundance and biomass of zooplankton in samples. In Downing, J. A. & F. H. Rigler (eds), A Manual on Methods for the Assessment of Secondary Productivity in Fresh Waters. Blackwell Scientific, Oxford: 228–265.Google Scholar
- Schaus, M. H., 2007. Effects of Biomanipulation on Nutrient Cycles in Central Florida Lakes via Nutrient Excretion and Bioturbation by Gizzard Shad. Project #SK933AA, Final Report. St. Johns River Water Management District, Palatka, FL.Google Scholar
- Schaus, M. H., W. W. Morris & A. Ford, 2010a. Quantifying the Role of an Omnivorous Fish in Central Florida Lakes: Diet Analyses and Simulation Modeling. Project #25244, Final Report. St. Johns River Water Management District, Palatka, FL.Google Scholar
- Schaus, M. H., W. Godwin, L. Battoe, M. Coveney, E. Lowe, R. Roth, C. Selecky, M. Vindigni, C. Weinberg & A. Zimmerman, 2010b. Impact of the removal of Gizzard Shad (Dorosoma cepedianum) on nutrient cycles in Lake Apopka, Florida. Freshwater Biology. doi: 10.1111/j.1365-2427.2010.02440.x.
- Shapiro, J., V. Lamarra & M. Lynch, 1975. Biomanipulation: an ecosystem approach to lake restoration. In Brezonik, P. L. & J. L. Fox (eds), Proceedings of a Symposium on Water Quality Management through Biological Control. University of Florida, Gainesville, FL: 85–86.Google Scholar
- Tugend, K. I. & M. S. Allen, 2000. Temporal dynamics of zooplankton community composition and mean size at Lake Wauberg, Florida. Florida Scientist 63: 142–154.Google Scholar
- Van Den Avyle, M. J. & R. S. Hayward, 1999. Dynamics of exploited fish populations. In Kohler, C. C. & W. A. Hubert (eds), Inland Fisheries Management in North America. American Fisheries Society, Bethesda, MD: 127–166.Google Scholar
- Vanni, M. J., 1995. Nutrient transport and recycling by consumers in lake food webs: implications for algal communities. In Polis, G. A. & K. O. Winemiller (eds), Food Webs: Integration of Patterns and Dynamics. Chapman and Hall, New York: 81–95.Google Scholar