Avaliação dos efeitos das mudanças climáticas globais sobre estoques pesqueiros com diferentes estratégias de vida

Abstract

The effects of the increase in temperature due to global climate changes are directly related to fish survival and, therefore, with their natural mortality (M). This parameter is one of the most important in the fish stocks assement and considering the uncertainties in the estimates of M is fundamental for the success of the management of these stocks. In addition, the patterns found in the uncertainties of M can be used in more holistic approaches, based on groupings of species with different characteristics of life history. To mathematically model these uncertainties, the Fuzzy Set Theory was used to evaluate the effects of the temperature increase on M and, consequently, on the Recruit Yield (Y / R) of fish with different life strategies, considering the scenarios of the IPCC (Intergovernmental Panel on Climate Change). The generated models confirmed that the increase in temperature causes an increase in M and a decrease in Y / R for all species, mainly comparing the current scenario and the most pessimistic scenario of the IPCC. In addition, species with opportunistic life history characteristics were those with the greatest increase in M, decrease in Y / R and highest uncertainties in M and Y / R. Intervals with maximum sustainable yield possibilities (MSY) and their respective fishing mortality (FMSY) were also estimated, providing biological reference points (PRB) for fisheries management. Species with opportunistic life history characteristics showed greater variation in decreasing MSY. As these species are more prone to risk, due to their greater uncertainty, more conservative scenarios are recommended when choosing PRBs for these species. Therefore, the present study contributed to fisheries management by addressing the uncertainties inherent in the effects of global climate change and in stock management based on groupings of species with different characteristics of life history.