Conservation status and spatiotemporal distribution of fish with socioeconomic importance in the Amazonia-Cerrado transition zone

ABSTRACT On the southern edge of Brazilian Amazonia, within the Araguaia-Tocantins Basin, the Araguaia River and its main tributary, the Mortes River, are of high ecological, geopolitical and socioeconomic importance. Understanding the effect of climate on fish distribution is vital for sustainable resource management. We aimed to apply spatiotemporal distribution models for a past (Last Glacial Maximum, LGM), current and future climate scenario for the most fished and commercially relevant fish species in the Mortes River Basin. The species with the highest fishing frequencies were Pseudoplatystoma fasciatum (90%), Brycon falcatus (74%), Myloplus torquatus (68%) and Leporinus friderici (39%). The environmental variables that best explained the spatial distribution of these species were altitude, temperature, and precipitation. Our projections revealed that all species had extensive areas of continuous and connected environmental suitability niches (ESNs) during the LGM. The current geographic distribution of the species is determined by environmental conditions, however, the predicted ESNs overlap with areas under intense agricultural exploitation. In a pessimistic future scenario, with increase in temperatures, B. falcatus and P. fasciatum could disappear, while M. torquatus and L. friderici could adapt by modifying their ESNs. Currently, the protected areas in the studied basin do not adequately represent the habitats with higher environmental suitability for the occurrence of these species. More effective initiatives to protect and manage fishery resources are needed in the Araguaia-Tocantins and Mortes basins to allow for sustainable conservation policies.