Influência da precipitação e escoamentos dos rios na abundância do camarão na baía de Maputo

Abstract

Maputo Bay is an estuarine area where the existence of mangroves and high amounts of nutrients is conducive to the development of fishing resources such as shrimp. However, this resource presents seasonal and interannual fluctuations that have been associated with the influence of environmental factors, namely rainfall and runoff. In the present work, the time series of the environmental conditions of shrimp catches, fishing effort and shrimp abundance index were statistically analyzed and then linear relationships between the average annual abundance index of shrimp captured by the semi-industrial fleet of Maputo Bay were tested. and precipitation and runoff from the Maputo and Incomati rivers. The results show that the catches of the shrimp of the species Fenneropenaeus indicus follow a seasonal regime, with a negative exponential trend; linear regression tests showed statistically significant relationships between the total shrimp yield and the total rainfall in the previous year, as well as between the total yield and the runoff index of the Maputo and Incomati rivers. However, the same analyzes applied to F. indicus did not show significant linear relationships between yields and environmental conditions. The models only explain a part of the fluctuations in shrimp yield, so it is concluded that the abundance of shrimp in Maputo Bay does not depend only on rainfall and runoff, but probably also on other biotic, abiotic and effort factors. fishing. The results obtained are important, because they allow us to affirm that the precipitation and runoff of the rivers influence the shrimp abundance, which may lead, after more in-depth studies, using multiple regression models to achieve the prediction of catches based on fluctuations of that environmental factor, allowing to improve the management, not only of this type of fisheries, but also of the hydrographic basins that flow into these ecosystems.