The Mediterranean Sea is now recognized as a hotspot of global change, ranking among the fastest warming ocean regions. In order to project future plausible scenarios of marine biodiversity at the scale of the whole Mediterranean basin, the current challenge is to develop an explicit representation of the multispecies spatial dynamics under the combined influence of fishing pressure and climate change.

This study used an integrated modelling chain including a high-resolution regional climate model, a regional biogeochemistry model and a food web model to project the potential effects of climate change on biomass and catches for a wide array of species in the Mediterranean Sea.

The results show that projected climate change would have large consequences for marine biodiversity by the end of the 21st century under a business-as-usual scenario.

The study found that that total biomass of high trophic level species (fish and macroinvertebrates), as well as total catch, are projected to increase. However, these global increases masked strong spatial and inter-species contrasts. The bulk of increase in catch and biomass would be located in the southeastern part of the basin while total catch would decrease in the western part. Additionally, it is highlighted that winner species would mainly belong to the pelagic group, being thermophilic and/or exotic, of smaller size and of low trophic level, while loser species are generally large-sized, some of them of commercial interest.

It is concluded that given the already poor conditions of exploited resources, the obtained results suggest the need for fisheries management to adapt to future changes and to incorporate climate change impacts in future management strategy evaluation.

Moullec et al. (2019) An end-to-end model reveals losers and winners in a warming Mediterranean Sea. Frontiers in Marine Science 6:345.