Fish diversity in the Upper Paraguay River Basin: implications for fish conservation and fishing sustainability

Abstract

This study addresses the current gaps in understanding fish richness and composition patterns within the Upper Paraguay River Basin (UPRB) and explores the primary drivers influencing these patterns. Additionally, it conducts a comprehensive review of fishing activities in the basin, particularly focusing on the Pantanal wetland. The findings highlight the role of area in shaping freshwater fish richness at the sub-basin scale due to the environmental heterogeneity. Along the altitudinal gradient, fish richness decreases. Regarding the composition, the UPRB displays high β diversity, primarily driven by species turnover. The Paraguay River serves as a crucial connector among sub-basins, while upland areas contribute significantly to the overall diversity of fish species. There are high negative impact projects implemented and planned to be installed in the Upper Paraguay river basin that put at risk one of the greatest fish diversities in the world and are ignored by decision makers in fisheries management in the region. Therefore, to safeguard fish diversity and ensure fisheries sustainability in the UPRB, we recommend based on the results obtained: (i) increased representation of Conservation Units focused on aquatic ecosystems in upland areas; (ii) providing greater incentives for ichthyological research, given the substantial ecological and economic value of fish to the region, alongside studies aimed at comprehending fisheries and socio-ecological dynamics; and (iii) the integration of scientific insights and active involvement of fishers in fisheries management processes.