Fish skeletal anomalies from the 1991--1993 Environmental Monitoring and Assessment Program (EMAP)-Louisianian Province

Measurement of skeletal deformities in fish has been proposed as a means of monitoring pollution effects in marine environments. Effects of organic and inorganic contaminants on bone integrity are similar in that vertebral anomalies are produced, although they may develop through different modes of action. Fishes (3,800) sampled during the 1991--1993 Louisianian Province EMAP project were xrayed and skeletal anomalies were classified according to Bengtsson and Bengtsson (1983). In general, deformities were found only at sites with contaminated sediments and appeared to be related to areas having industrial contamination or low dissolved oxygen. The incidence ranged from 0 to 23%. A significant longitudinal gradient was observed with western Sites of the Gulf of Mexico having a frequency of deformities that was 2x greater than those observed in the eastern part.