THE EFFECT OF FISH HATCHERY EFFLUENT ON PERIPHYTON IN FISHING CREEK, FREDERICK COUNTY, MARYLAND

Abstract

An assessment was performed on a second order stream in Frederick County, Maryland, to determine the effect of aquaculture ponds on the periphyton community. Artificial substrate periphyton samplers were placed in the stream at locations above and below the aquaculture facilities for a 26 day period. Variables affecting periphyton growth (light intensity, stream velocity, and stream depth) were monitored for each location. Water chemistry analysis was performed to determine chemical changes caused by the aquaculture. A generic taxonomic analysis of algae was performed at sites above and below the aquaculture facilities. Published methodology for periphyton and chemical analysis were adapted and used for this study. Chlorophyll-a (mass meter­­­­­¯²) and Ash-Free Dry Weight (mass meter­­­­­¯²) were found to be statistically higher downstream of the aquaculture facilities when controlling for stream velocity. The Autotrophic Index was found not to be impacted by the aquaculture but was related to stream velocity. Problems with the extraction efficiency of chlorophyll-a may have caused an under reporting of chlorophyll-a mass and therefore an over reporting of Autotrophic Index numbers. Chemical analysis of the stream showed little impact from the aquaculture facilities. Although the aquaculture facilities appear to cause an impact on the periphyton community, the level of impact appears small.