What's good for fish is good for fishes: Interspecific consistency of growth, condition, and abundance among glacial lakes

Abstract

ObjectiveFish abundance and growth is regulated by a combination of bottom‐up and top‐down forces but many management techniques depend more heavily on the later. Here we evaluate if inter‐system variation in nutrient loading and bottom‐up forces play more dominant roles in control of abundance and growth of species across similar lakes than intra‐ and inter‐specific compensatory effects. We aim to assess whether patterns of abundance and growth are consistent among fish species across.MethodsWe test this by evaluating pairwise comparisons of catch‐per‐unit‐effort (CPUE), condition, and length‐at‐age data for eleven common warmwater fish species from 184 meso‐ and eutrophic glacial lakes in Indiana, USA. We characterize environmental conditions of each lake using limnological measurements (e.g., chlorophyll‐a concentration and surface temperature), lake morphology descriptions (e.g., depth and size), catchment characteristics (e.g., percent agricultural landcover), and nutrient load modeling using Long‐Term Hydrologic Impact Analysis (L‐THIA). Taking a meta‐analysis approach, we use effect size calculation from pairwise correlations among lakes to identify environmental and community impacts on species abundance, condition, and length‐at‐age.ResultWe demonstrate that there are positive associations among most species comparisons (i.e., multiple species experiencing relatively fast growth in the same lake). Evaluations of environmental conditions among systems suggest that differences in estimated phosphorus input, and the limnological measurements of total phosphorus, Secchi depth, and chlorophyll‐a concentration are good predictors of length‐at‐age, and CPUE for fish.ConclusionOur results indicate that there is a strong and consistent influence of environmental conditions and bottom‐up processes in determining species abundance and growth. This suggest that bottom‐up forces and environmental conditions linked to nutrient loading likely determine the upper‐boundary of fish abundance and growth in these lakes.