Efeitos dos eventos climáticos locais no recurso pesqueiro do tambaqui da Amazônia Central

Abstract

Climate change is the greatest threat to biodiversity and its effects already threaten freshwater ecosystems. There is abundant evidence that the Earth's climate is changing more rapidly now than in earlier periods with potential effects on the Amazon basin and its organisms. This study evaluated the climatic impacts on tambaqui fish stocks (Colossoma macropomum), their sustainability and created a model that describes the levels of these impacts as well as an inference system that aggregates the subjective information of fishing experts and environmental variables to the parameters that are determined for the recruitment in the fishing activity on these stocks. A survey of information on the status of tambaqui production and changes in fishing dynamics of this species was carried out from the main port of Manacapuru in the period from 2014 to 2016, including interviews with fishermen from Manacapuru. Fishermen's perception of extreme flood and drought events was studied in the city of Manacapuru and, finally, a new methodological approach was used that uses fuzzy mathematics and multi-criteria decision makers to create scenarios and inference systems. We characterize the environmental variables and define the linguistic variables incorporating the subjective information of the experts and create the criteria giving weights according to their degree of influence on the impact, adding also the effects of the fishing. We defined pertinence functions that indicated the degrees of expected impacts according to the variation found or estimated in the environment. The results show the scenarios and stock status and their sustainability according to climatic variations and fishing pressure. A conceptual model has been developed for impact assessments in the Amazon Basin that can be applied to other species of the basin, helping future studies that aim to compare the local impacts of extreme events.