Development of Ecopath Models for Florida Lakes We are currently analyzing a wide range of historical fish and plant community samples from Florida lakes. Our goal is to develop Ecopath models that could be used to predict how habitat manipulations (herbicide use, drawdowns and muck removals) would influence lake fish communities. This project is led by Dr. Mark Rogers with Allen as a Co-Principal Investigator, and funding is provided by the Florida Fish and Wildlife Conservation Commission. A Largemouth Bass Model for the Kissimmee Chain of Lakes (KCOL) This project seeks to use historical fisheries data from the KCOL to evaluate how changes in water level regimes and aquatic plant abundance and species composition would influence largemouth bass fisheries. The model includes a wide range of FWC and UF sampling efforts at the KCOL, and should provide resource managers with a tool that can be used to address policy options at this important Florida ecosystem. Patrick O'Rouke is an MS student working on this project, which is funded by the South Florida Water Management District. Assessing Effects of Gizzard Shad Removal on Nutrient Cycling and Gizzard Shad Population Dynamics Reversing the effects of eutrophication can be challenging and requires the reduction of external nutrient sources and internal nutrient loading. Omnivorous gizzard shad Dorosoma cepedianum can facilitate nutrient loading from the sediments as a consequence of their foraging activity at the sediment-water interface and subsequent excretion of nutrients in the water column. This feeding activity may contribute considerably to the release of nutrients from the sediments in eutrophic Florida lakes. Biomanipulation via removal of gizzard shad has been proposed as a management strategy for improving water clarity by reducing internal nutrient loading from the sediments. Preliminary studies at Lake Denham, Florida, suggested that strong biomass reductions of gizzard shad using haul seines may reduce phytoplankton biomass. Recently, biomanipulations have been attempted on several lakes of the Harris Chain of Lakes, Florida using gill nets, but the results of these efforts have yet to be experimentally evaluated. Understanding how fish life history metrics respond to density reductions is critical to understanding the potential impact of biomanipulation on lake food webs. We used a whole-lake gizzard shad reduction experiment (i.e., a biomanipulation) to 1) assess impacts of a commercial gizzard shad removal on their population dynamics (i.e., recruitment, growth, mortality), 2) measure diet contents of gizzard shad to indicate mode of feeding, 3) explore the potential for gizzard shad removal to influence lake water quality, and 4) evaluate the potential for bycatch impacts on black crappie Pomoxis nigromaculatus fisheries. Matt Catalano is the Ph.D. candidate in charge of this project, which is funded by the SJRWMD, FWC, and SFWMD. |
Size Selectivity of an Otter Trawl for Black Crappie at Five Florida Lakes |
Fish Community Composition in Tussock Forming Aquatic Macrophytes at Two South Florida Lakes |
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