Predicting the current and future suitable habitat distributions of the anchovy (Engraulis ringens) using the Maxent model in the coastal areas off central-northern Chile

An assessment of climate change impacts on the habitat suitability of fish species is an important tool to improve the understanding and decision-making needed to reduce potential climate change effects based on the observed relationships of biological responses and environmental conditions. In this study, we use historical (2010-2015) environmental sea surface temperature (SST), upwelling index (UI), chlorophyll-a (Chl-a) and biological (i.e., anchovy adults acoustic presence) data (i.e., Maxent) to determine anchovy habitat suitability in the coastal areas off central-northern (25 degrees S-32 degrees S) Chile. Using geographic information systems (GIS), the model was forced by changes in regionalized SST, UI and Chl-a as projected by IPCC models under the RPC (i.e., RCP2.6, RCP4.5, RCP6.0 and RCP8.5) emissions scenarios for the simulation period 2015-2050. The model simulates, for all RCP scenarios, negative responses in anchovy presence, reflecting the predicted changes in environmental variables, dominated by a future positive (warming) change in SST and UI, and a decrease in chlorophyll-a (i.e., phytoplankton biomass). The model predicts negative changes in habitat suitability in coastal areas from north of Taltal (25 degrees S) to south of Caldera (27 degrees 45 ' S) and in Coquimbo littoral zone (29 degrees-30 degrees 12 ' S). The habitat suitability models and climate change predictions identified in this study may provide a scientific basis for the development of management measures for anchovy fisheries in the coastal areas of the South American coast and other parts of the world.