Lake Panasoffkee SWIM Plan - Southwest Florida Water ...

Management for Maintenance of Aquatic Plant Coverage
Lake Panasoffkee is a plant dominated lake, rather than a phytoplankton dominated lake.
This coupled with groundwater as a major source of inflow to the lake gives Lake Panasoffkee
its good water quality, especially in terms of clarity. Submersed vegetation in the lake has
historically been dominated by eelgrass (Vallisneria arnericana), with smaller areas of coontail
(Ceratophyllurn dernersurn), southern naiad (Najas guadalupensis), parrot feather
(Myriophyllurn aquaticurn) and pondweed (Potamogeton illnoensis).
Workers at the University of Florida have demonstrated that lakes with 50-60 percent
coverages of aquatic plants tend to be clear lakes. Reducing aquatic plant coverage below
this threshold may shift the lake to a phytoplankton dominated system. Therefore, especially
during the dredging of the lake, it is imperative that vegetation maps are available to monitor
plant coverages throughout the lake. This information can also be used to evaluate increases
or decreases in areal coverage of undesirable aquatic plants such as hydrilla.
Management of Existing Water Quality
Water quality in Lake Panasoffkee is considered good due primarily to a large groundwater
contribution, dense stands of aquatic plants and the predominantly rural character of the
watershed. However, groundwater in the region is vulnerable to the transmission of
contaminants due to the lack of confinement of the aquifer and surface water systems can
collect and convey non-point source pollutants. Fortunately, the District's recent purchase
of more than 9,000 acres on the eastern shore of Lake Panasoffkee protects 25 percent of the
basin from development which will also protect water quality. To ensure that water quality is
protected, routine monitoring should be implemented to provide an early warning of
deteriorating water quality conditions.
Management of Fisheries and Evaluation of Restoration on Fish Populations
Fish Food Survey: Macroinvertebrate Diversity, Abundance and Distribution -The Council's
Advisory Group noted what appears to be a scarcity of macroinvertebrates (a group of animals
without backbones that includes snails, clams and aquatic insects and worms) in lake
sediments and on much of the submersed vegetation. It is possible that macroinvertebrate
abundance should be low given the generally inorganic nature of the sediments and the fact
that submersed vegetation is typically encrusted or covered with precipitated calcium
carbonate. However, the lake is known or was known to produce a quality redear sunfish
fishery. Redear sunfish are specially adapted to feeding on snails and mussels. It is also
known that extensive deposits of unbroken snail shells can be found in certain areas of the
lake and, in fact, serve as bedding areas for these sunfish. The occurrence of these snail
shell deposits and the fact that these shells are unbroken are evidence that snail production
was high in Lake Panasoffkee. Only cursory examinations have been made of the lake's
macroinvertebrates; there is a need to quantify the abundance, diversity and distribution of
macroinvertebrates in the lake since macroinvertebrates are a significant source of food for
fish.