Environmental variability and energetic adaptability of the king scallop, Pecten maximus, facing climate change.

The main objective of this project is to describe the energetic strategy (growth and reproduction) of P. maximus according to the variability of its environment (food resources, temperature and seasonality). Three different stations of the biogeographical area of P. maximus will be studied : two contrasted coastal environments, 1) the Bay of Brest and 2) a coastal site in Western Norway (Bjørnafjord) and 3) a deeper water site in Iroise Sea. Results should help in evaluating the impact of global change on the adaptation of metabolism of great scallop among its biogeographical area. It will also help in managing and improving sustainable aquaculture and fisheries of king scallops (seasonal bioenergetics needs, dynamics of physiological effects of temperatu re, effects of food availability on growth, etc.). High frequency in situ monitoring of environmental conditions will be conducted in coastal stations during the spring productive period. We will try to characterize the different potential trophic resourc es using a combination of several proxies : stable isotopes, fatty acids, pigments, measured in the digestive gland. Experimental study of isotopic composition will allow to understand incorporation and fractionation mechanisms. Physiological parameters ( filtration rate, assimilation rate, respiration, etc.) will be assessed through ecophysiological experiments on both French and Norwegian scallops. Common garden experiments will be carried out on these populations to assess the variability of the physiol ogical parameters. Starvation experiments will also be set up to have relevant idea of the minimum level of reserve in the organism and a measure of the energy necessary to its maintenance. Data from previous monitoring will be added to our results to set up an individual bio-energetic model for P<; maximus, based on the theory of the Dynamic Energy Budget (DEB). This model will be calibrated and then used to describe growth and reproduction in the third location.