Summary

Description

From February 16 to May 6, 1988, sixteen largemouth bass, fifteen bluegill, and thirteen brown bullhead, were collected from three fresh water ponds at St. Vincent National Wildlife Refuge, Franklin County, Florida. Composite whole body samples of each species were analyzed for mercury and selenium. Mercury concentrations likely to be present in the edible portion fillet of these species were estimated from the wholebody value. Largemouth bass ranged in length from 197 to 460 mm 7.718.1 in.. Bluegill were from 145 to 240 mm 5.79.4 in. in length, and brown bullhead were 302 to 363 mm 11.914.3 in. long. Mercury concentrations in all species were below 0.25 mgkg wet weight, except for bluegill 0.27 in Oyster Pond. Selenium may, in some cases, mitigate the adverse biochemical andor physiological effects of mercury. Selenium has also been found to be toxic to wildlife in large amounts. Selenium concentrations in all composite samples were 0.2 mgkg, wet weight. Neither mercury nor selenium were found to occur at levels believed to be toxic to individual fish or human consumers. However, the mercury concentrations found in the fish may constitute some risk to predators that regularly consume them.