Climate-induced shifts in marine fish larval assemblages and communities of harvested species in the Southwestern Atlantic Ocean

Shelf regions in the Southwestern Atlantic Ocean support one of the six richest hot spots of marine biodiversity in the Southern Hemisphere. In contrast, this region is within the warming hotspots in the ocean. Climate change... [ view full abstract ]

Shelf regions in the Southwestern Atlantic Ocean support one of the six richest hot spots of marine biodiversity in the Southern Hemisphere. In contrast, this region is within the warming hotspots in the ocean. Climate change will modify ocean circulation in the Southwestern Atlantic Ocean, and consequently affect species distribution patterns. Since early life stages of fish and adult population are related through the life cycle, we investigated the climate-induced changes in the distribution of fish larval assemblages and communities of harvested species in the Southwestern Atlantic Ocean through a community-based modelling approach. For that, we used gradient forest models to predict the influence of two climate change scenarios (RCP 4.5 and 8.5) to answer our two main questions: could climate change affect the distribution, abundance and composition of fish larval assemblages, and will communities of harvested species follow the same trends? Community-based approaches, such as gradient forest, have the advantage of using information from all species together, rather than species distribution approaches that treat each species independently. We found that fish larval assemblages and harvested communities are likely to move southwards and show a coastal-offshore gradient towards the coast. Also, higher expected changes are projected for the RCP 8.5 and in the southern portion of the study area for both fish larval assemblages and harvested species. These results are a first-step in predicting climate change impacts in biological communities in the Southwestern Atlantic Ocean and can bring substantial contributions to conservation and fisheries management.