DISTRIBUIÇÃO DO ICTIOPLÂNCTON NA BACIA DO RIO BACANGA E SUA RELAÇÃO COM AS ALTERAÇÕES DA PAISAGEM: SUBSÍDIOS PARA A CONSERVAÇÃO DA PESCA NA AMAZÔNIA COSTEIRA

Abstract

The Amazon region of Maranhão is suffering from fragmentation of vegetation in its river basins. The Brazilian Amazon coast, rich in mangroves, is home to a vast and complex network of rivers and estuaries. The Amazon region in Maranhão has lost more than 75% of its originais forest cover due to illegal deforestation and disorderly urbanization, leading to the occupation of sensitive areas, socio-environmental impacts, poor sanitation, and the compromise of water bodies and public health. This study investigated the relationship between landscape changes in the Bacanga River basin and the abundance/distribution of fish eggs and larvae, considering land use and occupation. The objective was to analyze the interference in the sustainability of local fishing, using a qualitative-quantitative approach, focusing on the interaction with fishermen in the region. The Bacanga basin, strategic for São Luís, is socio-environmentally important for its culture, conservation unit, archaeological sites, water network, biodiversity and fishing. However, anthropogenic pressures threaten artisanal fishing, which is essential for the subsistence of families in the Itaqui-Bacanga region. This study, due to its interdisciplinary importance, presents two chapters. The first, "Seasonal and spatial patterns of ichthyoplankton in the Bacanga River estuary, Brazil: environmental controls and conservation challenges", investigates the distribution of fish eggs and larvae in the basin. The results indicate that the abundance and composition of ichthyoplankton are influenced by seasonality and spatiality, with higher concentration downstream and in transition periods. Anthropogenic impacts were observed, such as pigmented eggs and larvae, due to anthropic influences, and the presence of exotic species. The species Anchoa sp. and Atherinella brasiliensis were dominant in the Bacanga basin. The second chapter, "Anthropogenic interference and conservation of spawning grounds in the Bacanga River basin: a study on the sustainability of local fishing", carried out the collection of ichthyoplankton in four seasonal campaigns (2023-2024). Additionally, questionnaires were administered to fishermen to investigate their perceptions about fishing and the environmental impacts on the basin. The analysis of land use and occupation over three decades demonstrated urban expansion and reduction of natural vegetation, especially mangroves. The CCA revealed the influence of these changes on the spatial distribution of fish eggs and larvae, with specific species associated with less anthropized environments. Interviews with fishermen indicated a decline in traditional species and the emergence of uncommon ones, suggesting changes in the ichthyological composition. The fishermen's perception of the impacts of local pollution on fishing and the importance of integrating scientific knowledge and traditional knowledge to support conservation strategies in spawning grounds, promoting the sustainability of regional fishing through socio-environmental approaches, became evident.