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ASSESSING FISH TISSUE CONTAMINATION ON A REGIONAL SCALE
Citation:
Lazorchak, J M., F H. McCormick, A. T. Herlihy, T R. Henry, S P. Bradbury, AND R. B. Yeardley Jr. ASSESSING FISH TISSUE CONTAMINATION ON A REGIONAL SCALE. Presented at International Congress on Ecosystem Health: Managing for Ecosystem Health, Sacramento, CA, August 15-20, 1999.
Description:
The selection of target fish species for assessing the extent of fish tissue contaminants is a critical consideration in regional stream surveys such as the Environmental Monitoring and Assessment Program (EMAP). The ideal species would be widely distributed and common, bioaccumulate chemicals of concern, and be consumed by piscivorous wildlife. In first- to third- order streams, small, short-lived forage fish, i.e., minnows (F. Cyprinidae), darters (F. Percidae), and sculpins (F. Cottidae), are more widely distributed and found in greater numbers than species whose adults grow to large size, i.e., suckers (F. Catostomidae), trout (F. Salmonidae), bass and sunfish (F. Centrachidae) and carp (F. Cyprinidae). The small forage fish are less mobile, often occur in larger numbers, and generally have smaller home ranges than the bigger fish. Thus, small forage fish usually provide a sufficient sample for chemical analysis and may represent an approximation of the "site average" of accumulated tissue contaminants. Analysis of fish collections from the 1993-94 Mid-Atlantic Highlands Assessment (MAHA) showed that small forage fish were more widely distributed than larger species. Regional assessments of fish tissue contaminants were made for Chlordane, DDT and Metabolites (DDT), Dieldrin, Endrin, Hexachlorobenzene, Mercury, and Polychlorinated Biphenyls (PCBs). Using the percent of stream miles exceeding the wildlife effects thresholds as a basis for comparison, regional assessments based on small, forage fish were not significantly different from regional assessments using large fish. Small, short-lived fish may, therefore, be an excellent choice as target species for conducting regional fish tissue studies and wildlife problem formulations.