How to maintain scallop fisheries in face of toxic algal blooms?
The MaSCoET project, is coordinated by Ifremer’s Research Unit DYNECO and strongly involves our Laboratory. It aims to better understand the harmful algal blooms of Pseudo-nitzschia and their consequences on the scallop fisheries.
The scallop is the third species sold at French fish auctions. It is exploited from the north of France to the Pertuis Charentais. Since the 2000s, professionals all along the coast have been forced to close down fishing grounds due to the blooms of the microalgae Pseudo-nitzschia, which can produce amnesiating toxins that make shellfish unsafe for human consumption. These closures may result in a shift of fishing to another species, the black scallop.
Several aspects of these contaminations are still being questioned by scientists. How do blooms develop from one site to another? Why does scallop decontaminate slowly compared to black scallops? Is the black scallop resource sufficient to compensate for scallop closures? The MaSCoET project (Maintenance of the shellfish stock in the context of toxic blooms) aims to answer these questions and make recommendations to fisheries managers to enable the development of management tools in conjunction with the fishermen.
Ongoing measurements following a first efflorescence of Pseudo-nitzschia
Monitoring of blooms has already begun since early March, with regular water sampling by scientific teams to follow a first episode of Pseudo-nitzschia detected by REPHY (Réseau d’observation et de surveillance du phytoplancton et des phycotoxines) at the Finistère peak.
A workshop site in the bay of Brest will be more particularly monitored for shellfish contamination and scallop population monitoring. Fine analyses on shellfish at different stages of contamination will be carried out at the Tinduff hatchery (29) and in the laboratory. The black scallop population will be assessed through a campaign of fishing, with measures of abundance. This scientific field work will be complemented by the development of numerical calculation tools. The project will thus make it possible to better understand the phenomena studied, test hypotheses or scenarios with the objective of ultimately leading to management proposals and/or scenarios.
The MaSCoET project is mainly financed by FFP (France Filière Pêche) but also by Brest Métropole, for a period of 5 years. It is led at the scientific level by DYNECO (coordinator) and LEMAR, in partnership with several fisheries committees (CDPMEM29, CDPMEM22, CRPMEM Bretagne, CDPMEM17, CRPMEM Normandie, CDPMEM56 and COREPEM) and with the support of the Tinduff hatchery.
Photo Credit: Ifremer – Xavier Caisey