Understanding the response of the Western Mediterranean cephalopods to environment and fishing in a context of alleged winners of change.

Increasing impacts of both fisheries and climate change have resulted in shifts in the structure and functioning of marine communities. One recurrent observation is the rise of cephalopods as fish recede. This is generally attributed to the removal of main predators and competitors by fishing, while mechanistic evidence is still lacking. In addition, climate change may influence cephalopods due to their high environmental sensitivity. We aim to unveil the effects of different anthropogenic and environmental drivers at different scales focusing on the cephalopod community of the Western Mediterranean Sea. We investigate several ecological indicators offering a wide range of information about their ecology, and statistically relating them with environmental, biotic and fisheries drivers. Our results highlight non-linear changes of indicators along with spatial differences in their responses. Overall, the environment drivers have greater effects than biotic and local human impacts with contrasting effects of temperature across the geographic gradient. We conclude that cephalopods may be impacted by climate change in the future while not necessary through positive warming influence, which should make us cautious when referring to them as generalized winners of current changes. • Effects of environmental, biotic and human drivers were investigated for ecological indicators of cephalopods. • Dynamics of this taxon are mainly influenced by sea temperature, explaining geographical gradients in several metrics. • Relationships with biotic variables could hint at the decrease of high trophic fishes. • Fishing has little effect on cephalopods with β-diversity being the only indicator influenced by this variable. • Potential negative effects of warming on indicators challenge the idea of cephalopods as a climate change winners. [ABSTRACT FROM AUTHOR]