Adaptation of oyster-farming ecosystems to global change – GIGASSAT

Since the 1970s, disease epidemics, mass mortalities, harmful algal blooms and other population explosions have been occurring in marine environments at a historically unprecedented rate due to climate change. Shellfish aquaculture is vulnerable to global warming because it increases the incidence of disease. In France, oyster farming is the most important aquaculture industry. However, this industry, which is based on the exploitation of the Pacific oyster Crassostrea gigas, is currently undergoing the most serious crisis since the introduction of the species in the 1970s. Severe mass mortalities of 1-yr-old C. gigas have been occurring along all coasts of France since 2008 and are thought to be associated with a particular genotype of the Ostreid herpesvirus and several vibrio species. These mortalities have caused considerable concern among growers, associations and public authorities about the future of French oyster production. In response to this problem, the GIGASSAT project will develop an integrated and participative research program with and on the oyster-farming industry, focusing on both environmental and socio-economic dimensions of the impact of climate change. The GIGASSAT project proposes to observe, analyse and help to manage the effect of global change on oyster-farming ecosystems considering animal health and physiology, environment and economics. To broaden the range of solutions that can guarantee sustainable oyster-farming, GIGASSAT will to improve our knowledge of the industry though an interdisciplinary and multi-stakeholder approach favouring the development of new knowledge on ecology, physiology, pathology and epidemiology, husbandry, modelling, economics and social sciences. The project is organized in four parts: (1) observing overall changes in the oyster-farming ecosystem over the past 10-20 years in relation with the recent mass mortality events, and proposing trajectories to plan the sustainable development of oyster-farming ecosystems, (2) analysing the effect of environmental parameters on disease transmission and related mortality of oysters by means of lab and field experiments, (3) forecasting disease transmission and related oyster mortality by means of models, to further test the effect of disease control measures to improve eco-efficiency of the oyster industry in the context of global change, and (4) communicating the results to growers, associations and stakeholders. This project will run for 42 months and bring together 10 partners and 6 collaborators from institutional and industrial organizations.