| Resource management agencies and researchers have struggled to assess how changes in habitat composition and abundance will influence fish communities and fisheries. This research need pertains to both freshwater (lakes and rivers) and marine environments, and has been an increasingly important focus of fisheries management agencies over the last decade. Regarding freshwater systems, there is a need to identify plant types and abundances that foster high diversity and provide valuable habitat to sport fish. Ecosystem models offer the potential to explore how restoration projects that alter habitat quality and quantity will influence fish communities and fisheries.
The Florida Fish and Wildlife Conservation Commission (FWC) has conducted some of the largest lake habitat restoration projects in the world over the past two decades. In an effort to mediate effects of channelization and stabilized water levels on large lakes, and for aquatic plant management purposes, the FWC has used lake drawdowns and muck removals to improve littoral habitat. Drawdown and muck removal projects open areas to access by anglers and homeowners, but the benefits to fisheries have varied (e.g., Moyer et al. 2005; Allen et al. 2002) and impacts to lake-wide fish communities have not been measured. A key need for lake habitat restoration projects is the ability to set realistic objectives and measure the system’s responses relative to those objectives.
The goal of this project was to develop a spatially explicit ecosystem model for a generalized large Florida lake and use the model to explore how changes in habitat composition could influence fish community and sport fish abundance. Our objectives were to:
1) to analyze existing databases in Florida and evaluate the precision of estimates of fish biomass, density, community composition (e.g., total richness, density, and biomass of species groups) and 6 evaluate how they vary with aquatic plant species composition and abundance,
2) to develop an Ecopath model using input parameters from the historical data and other Florida studies, and
3) use the model to explore how changes in aquatic plant coverage and composition were predicted to influence fish community composition and abundance. |
