Climate warming vs ecological competition for marine tropical biodiversity and fisheries

Marine ecosystems, biodiversity and fisheries are under pressure worldwide because of global changes including climate warming and demographic pressure. In that regard, many scientists and stakeholders advocate the use of an ecosystem approach for fisheries integrating the numerous ecological and economic complexities at play, instead of focusing on the management of isolated target species. However, the way to operationalize such an ecosystem approach remains challenging, especially from the bioeconomic viewpoint. To achieve this, here we propose a model of intermediate complexity (MICE) relying on multi-species and multi-fleets dynamics. The model also takes into account climate change through a model of envelope for the biological growth of the fish species depending on the sea surface temperature. The model is calibrated for the small-scale fishery in French Guiana using time series of fishing landings and efforts from 2006 to 2018. From the calibrated model, we consider the business as usual (BAU) fishing intensity projection along with RCP climate scenarios derived from IPCC at the horizon 2100 in order to explore the impact of climate change on the ecosystem dynamics and on the fishery production. The results point out the detrimental impact in the long run of both climate change and ecological competition on fish biodiversity. The situation is particularly catastrophic in the pessimistic climate scenario as the results suggest the collapse of both biodiversity and fishing activities by 2100.