Projecting future climate change impacts on the distribution of pelagic squid in the Southern Ocean

Climate change is modifying the biogeography of many marine species. Squid (Cephalopoda) are important species of the Antarctic pelagic ecosystem, one of the areas most affected by climate change at the global level. The scarce knowledge on potential species distribution shifts in the Southern Ocean and the importance of squids in its pelagic ecosystem highlight the need to characterize how climate change may affect the distribution of these cephalopods in the future. Here, we project future trends for the distribution of 15 squid species from the Southern Ocean, using species distribution models (for the years 2050 and 2100) across 2 scenarios based on the Intergovernmental Panel for Climate Change (IPCC) Shared Socioeconomic Pathways (SSP1-2.6 and SSP5-8.5). A decline in habitat suitability at lower latitudes was observed for most squids, with no concurrent habitat increase at higher latitudes, mainly due to increases in temperature and sea ice retreat. Nevertheless, while Antarctic and subantarctic squid are projected to experience decreases in habitat suitability, subtropical and cosmopolitan squid may experience increases. The squids Histioteuthis atlantica , Teuthowenia pellucida , Todarodes filippovae and Bathyteuthis abyssicola are candidate winners, while Onykia ingens , O. robsoni , Martialia hyadesi , Gonatus antarcticus , H. eltaninae , Slosarczykovia circumantarctica , Mesonychoteuthis hamiltoni , Alluroteuthis antarcticus , Galiteuthis glacialis , Psychroteuthis glacialis and (specially) Moroteuthopsis longimana could lose to climate change. These changes may entail substantial implications for the trophic ecology of the Southern Ocean. Furthermore, squid movement into new ecosystems may increase top-down pressure over lower trophic levels, adding to the abiotic pressures implicit in climate change.