ENSO impacts on marine ecosystems and fisheries in the tropical and South Atlantic

Tropical and South Atlantic marine ecosystems support fisheries that have vital environmental and socioeconomic importance. In this Review, we outline how the El Niño–Southern Oscillation — a Pacific mode of sea surface temperature variability — influences Atlantic fisheries via teleconnections and cascading linkages between physical, biogeochemical and ecological systems. Connections are driven by tropical pathways (involving changes in atmospheric stability associated with the Walker circulation and tropospheric warming) and extratropical pathways (involving the Pacific–South American and Pacific–North American teleconnection patterns). Depending on the location, these pathways modify rainfall and river discharge, winds and upwelling, or a combination of both, impacting salinity, nutrient availability, primary production and, thus, fish recruitment, biomass and catch. Fishery responses are strongly species dependent, reflecting variations in behaviour between species to environmental factors (such as temperature, oxygen, salinity, habitat and food availability). This regional variability and species dependency, coupled with strong non-stationarity, highlights the complexity of El Niño–Southern Oscillation impacts on Atlantic marine ecosystems. This historical signal is projected to weaken in the future. Enhanced observational systems and refined ecosystem models are urgently needed to enhance predictive capabilities, reduce societal impacts and improve sustainable management in these regions.