Structural and functional characterization of the elasmobranch community of the Channel and North Atlantic in the context of global change

The objective of my thesis is to test the structural and functional responses of the elasmobranch community in the Channel and North Atlantic to global change over the last 70 years. Skates and sharks are particularly sensitive species and many of them have a degraded conservation status. The first axis aims at characterizing the structural fluctuations of the community which will be confronted with the observed temperature variations. We will use available data (Data Collection Framework (DCF), fisheries surveys, climatic data). The recent data will be compared to an analysis of the eDNA of the waters in the study area. On this basis, a second axis will test the links between fluctuations in abundance and the life traits of the species (e.g. age at maturity, sex ratio, physical condition, trophic level) and to define the levels of interaction and the real sympatry between some of these species (niche partition). Finally, the third axis will aim at the experimental analysis of the functional responses to temperature and pH variations in juveniles of 3 sympatric species: the curly ray and the brown skate, the former being more northern than the latter, and the dogfish which is not at the limit of its range.