Growth of Rock Bass, Ambloplites rupestris, in Relation to the Morphoedaphic Index as an Indicator of an Environmental Stress

Abstract

Atmospheric contamination by sulfur dioxide in the Sudbury region and the associated acidification has reduced population densities of fishes in the La Cloche Mountain lakes, 33–90 km away. Surviving rock bass (Ambloplites rupestris) responded to decreased abundance with increased growth rate. Variation in abundance among surviving populations could be monitored by means of individual growth rates and mean lake depth. Our findings suggest that growth rate of fishes, in conjunction with the morphoedaphic index, may serve as an indicator of environmental stress. Key words: environmental indicator, environmental stress, lake acidification, fish growth rate, morphoedaphic index, population density, rock bass