ABSTRACT
Since 1966, an increasing number of studies have reported the occurrence of external fish abnormalities (e.g., deformities, fin erosion, open sores, and tumors) in a variety of aquatic habitats (streams, lakes, estuaries, and marine) and discussed possible relationships between anomalies and environmental quality. Fish with external deformities, erosion, lesions, and tumors (neoplasms) were first observed by Ohio Environmental Protection Agency (Ohio EPA) biologists in 1979 while sampling a large urban stream, the Scioto River in downtown Columbus. Although all fish captured are identified and counted during Ohio EPA stream surveys, only fish that are weighed (individually, in aggregate, or by subsample) are examined for external anomalies at most sites. Sampling was conducted during the day except in the Ohio River, where night electrofishing was used for improved catches of most species. Each sampling site consisted of a fixed distance ranging from approximately 150 to 200 meters for wading methods and 500 meters fa boat-sampled sites.
