Assessment of fish yield in Patagonian lakes (Argentina):: Development and application of empirical models

The relationship between fish yield and basic homological information is important to developing sustainable management policies for lake fisheries, particularly when fish data are lacking. Most Patagonian lake fisheries lack the basic statistical information provided by bycatch and effort data. We present a simple first-order model of fish yield based on the relationship between fish biomass derived from hydroacoustic and gill-net surveys developed for 18 small Patagonian lakes. Such a model can be used to develop sound management guidelines that can be applied to the many unsampled small lakes of Patagonia for which basic limnological data are available. We also evaluated the value of well-known models developed from North American data sets. These models consistently underestimated fish yields in the Patagonian lakes, particularly as trophic level increased, illustrating the importance of using region-specific data to develop fish management guidelines. The poor predictive performance of the North American models could be related to climatic, limnological, and fish community differences between North American and Patagonian lakes.