Salmonid biomass and habitat relationships for small lakes

Lake morphometry and water chemistry were analyzed as predictors of brook trout and total salmonid biomass (brook trout, Atlantic salmon and Arctic char) in water bodies of Newfoundland. Lake morphometric variables included surface area, depth, perimeter and catchment area while water chemistry variables included conductivity/TDS and total Phosphorus. The broadly used Morpho-Edaphic Index was also assessed. Fish biomass/ha varied by an order of magnitude in the study lakes, despite similar water chemistry. Interactive stepwise multiple regression analysis suggested that Basin Permanence Index best explains brook trout biomass while surface area best explains the variance of total salmonid biomass in the relatively small, unproductive water bodies of Insular Newfoundland. In contrast, the Morphoedaphic Index performed poorly. The results suggest that biomass relationships with easily measured habitat variables such as surface area provide useful information, especially in management of water bodies under similar climate and nutrient regimes.