Twelfth International Conference on Climate Change: Impacts & Responses

Abstract

The spatial distribution of marine resources along the Colombian pacific coast is expected to shift due to global climate change, which is an important regional issue. Understanding the most likely future locations of the yellowfin tuna (YFT) species will help sustainable harvest and management. We estimated potential current and future distribution using the maximum entropy model (MaxEnt) based on species presence data and environmental variables (temperature, salinity, chlorophyll, dissolved oxygen, SSH, nitrates, phosphates, and currents). Future distributions of YFT in the 2020s, 2050s, and 2080s were modeled using temperature, salinity and currents projected under the Representative Concentration Pathway (RCP) 2.6, 4.5, and 8.5 scenarios for four ensembled global circulation models (GCM) (HadGEM2-ES, MPI-ESM-LR, MPI-ESM-MR, CNRM-CM5) obtained from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Pixel-wise change was calculated to identify areas of contraction and expansion, and the distribution core shift was determined to estimate the spatial movements. The results suggest that in the future, the YFT distribution area expansion at the depths between 0 and 27m and distribution contraction at deeper water indicating a vertical upward movement. The centroid of the current distribution is located between 5 °N and 78.5 °W. The distribution core shift for the short, medium, and long-term in the three RCP scenarios showed a northwestern shift indicating that the YFT could move away from the Colombian Pacific coast. A shift in the spatial and temporal distribution of this species may require a socioeconomic adjustment in the fishing industry.