Climatic and Morphoedaphic Indices of Fish Yields from Natural Lakes

Abstract

Fish production and yields from natural lakes are related to morphoedaphic factors and regional differences in climate. To quantify the relationships on a global scale, climatic data and estimates of fish yield, total dissolved solids, and mean depth were compiled for natural lakes located between 62°N and 15°S latitude. Stepwise regression analyses showed that for intensively fished lakes (N = 43), the climatic index “mean annual air temperature” accounts for 74% of the variability of maximum sustainable yield (MSY). The morphoedaphic index (MEI), expressed as total dissolved solids divided by mean depth, accounts for an additional 7-9% of the MSY variability. This contrasts with regional studies in which the MEI usually accounts for a greater percentage of yield variability than do climatic variables. Equations presented in this study can be used to predict approximate potential yields from lakes that are currently experiencing little or no fishing pressure.