The French king scallop (Pecten maximus ) is commonly harvested in Northern Brittany near coastal areas where summer blooms of the toxic dinoflagellate Alexandrium minutum usually occur. An experimental recirculating flume was used to study PSP contamination and detoxification patterns in scallops fed A. minutum and then non-toxic flagellates. Experiments were performed simultaneously with a set of five isolated individuals compared to a control (classical evaluation of ecophysiological parameters) and with two groups of 30 animals placed in a 100-L raceway (biodeposits method).At the individual level, the linear relationship between particulate organic matter (POM) and measurement of mean STX eq. per cell allowed comparison of real and calculated toxin absorption rates. Observations of the feeding physiology of scallop groups were subsequently analyzed using a general linear method describing the effects of the shift in food supply as well as the trend in the parameter studied when the diet was changed. Isolated scallops showed considerable interindividual variation in FTA values despite identical feeding conditions. Yet, regardless of the feeding activity of each individual, toxin uptake in tissues was always less than release in feces. Toxin absorption rates varied with time from one individual to another, but were always distributed in tissues in the following order: digestive gland > kidneys > other tissues. Mean bioaccumulation efficiency (Be) in tissues reached 17% for an absorption efficiency (Ae) of 43%. For both groups, feeding behavior at the time of the shift to a non-toxic diet changed drastically depending on the algal species used to detoxify the scallops. A diet based on Tetraselmis suecica appeared to stimulate biodeposition, clearance and filtration, whereas one based on Isochrysis galbana had the opposite effect. During detoxification periods following initial toxicity of either 150 or 350 µg STX.eq./100 g of meat, an average of more than two weeks was needed for toxin levels in scallops to reach the quarantine threshold. Toxin analysis in tissues also showed obvious STX neoformation in kidneys.