Fish catch management strategies: Evaluating the interplay between body size and global warming

Abstract

Environmental temperature and body size influence the life cycle of the species, with consequences for population size. In addition, it has been reported that increased temperature can lead to a decrease in body size. In the context of a resource-stock, whose abundance is diminished by the action of an endothermic predator and also by small-scale fishing activity, we analysed a Schaefer-type fishery model that incorporates parametric variables associated with thermal performance, metabolic theory, and warming. We project the biomass of the resource in a thermal tolerance range with an increasing temperature trend obtained from current data. In the short term there could be an increase in biomass. However, over time the stock will decline rapidly, in association with the intensity of temperature increase and fishing effort. Recommendations for Resource Managers 1. Temperature increments towards tolerance limits will generate that fish resources will eventually collapse locally. In the meantime, latitudinal variation in the physiological sensitivity of organisms will affect the outcome of the fishing effort differentially. 2. Planning for more sustainable harvesting requires an ecophysiological understanding of both the resource and the species with which it interacts. 3. Simple models contribute to the formulation of strategies aimed to guide responsible monitoring systems, where theoretical, observational, and experimental information is highly relevant.