V. P. Williams

Effects of Lake Bottom Channelization on Invertebrate Fish Food Organisms in Lake Tohopekaliga, Florida

The relationship between the decline of macroinvertebrate standing crop and the loss of aquatic habitat due to box-cut access channel construction was assessed on Lake Tohopekaliga. Channelization of natural lake bottom had an adverse effect on benthic productivity by increasing both taxon richness and numbers of organisms routinely utilized by sportfish. For this study, channel substrate supported only 54% of the total standing crop of fish food organisms found in littoral substrate. Macroinvertebrates associated with vegetation were eliminated by the destruction of rooted macrophytes;...

A Preliminary Evaluation of Blue Tilapia Population Expansion in Lake Tohopekaliga, Florida

Blue Tilapia (Tilapia aurea) were introduced to Florida in 1961. Subsequently they have become established throughout the central part of the state. Tilapia were first collected from Lake Tohopekaliga in 1976. Since that time a considerable expansion in both numbers and biomass has been documented. The juvenile tilapia population has increased by a rate of approximately 500% per year from 1979 to 1981. Blocknet samples taken in the fall of 1981 indicated that young of the year and adults of this species conservatively comprised 0.5% by number and 16% by weight of littoral zone fish...