Thèse de doctorat en Halieutique
Sous la direction de Jean-François Shumway et de Sandra E. Samain.
Soutenue en 2007
à Rennes, ENSA .
Hurmful algal blooms (HABs) are increasingly recognized as having profound effects upon economics of fisheries and aquaculture. Further, HABs are included in a list of concerns about changes in marine ecosystems that increase impacts of diseases and parasites on important resource species and the food webs that support them. This research assessed the interactions between HABs and bivalve molluscs. A number of specific HAB-bivalve interactions were studied, measuring fundamental physiological processes such as clearance and filtration rates of bivalves when exposed to pure cultures of HAB species or mixed benign and HAB cultures. Results indicate that clearance and filtration rates, as well as biodeposit production, were species specific. Further studies demonstrated the presence of intact HAB cells in the biodeposits with the ability to recover, suggesting potential risks for bivalves to be vectors of introduction of HABs into new environments. A simple method for mitigating this risk was demonstrated : keeping shellfish out of mater for 24 hr, or depurating at least 24 hr in quarantined seawater renders cells non-viable. Physiological responses of bivalve molluscs to HABs varied according to the algal/mollusc combination. This study further investigated whether these physiological