The Effect of Temperature on Paralytic Shellfish Toxin Uptake By Blue Mussels (Mytilus Edulis) and Sea Scallops (Placopecten Magellanicus)

Increasing amounts of paralytic shellfish toxins (PSTs) threaten human health, the economy, and marine ecosystems because of paralytic shellfish poisoning (PSP). Therefore, studies about shellfish toxicity can have significant public health and social impact. In this study, the effect of water temperature on PST uptake in blue mussels (Mytilus edulis) and sea scallops (Placopecten magellanicus) was tested. Mytilus edulis and P. magellanicus were acclimated to either 10°C or 15°C for two weeks before being fed with the toxic alga, Alexandrium fundyense, at a concentration of 100 cells/mL and a non-toxic algae source (Shellfish Diet) at a concentration of 2.4 X 103 cells/mL. At different time points, Alexandrium cell concentration was determined and individual shellfish were harvested and frozen. Whole mussel tissue, mussel tissue without the digestive gland, scallop tissue without the adductor muscle, and scallop adductor muscles were tested for toxicity using the Jellett Rapid Extraction method. Because the metabolic rates of M. edulis and P. magellanicus increase with temperature, PST uptake was expected to increase with temperature. The variation in uptake was high in mussels, and the mussels rapidly cleared toxic algae at both temperatures. One set of the scallops used for the experiment had been previously exposed to a harmful algal bloom. Because P. magellanicus retains toxin for a long time, the scallops were toxic prior to the experiment. Thus, the relationship between temperature and uptake could not be determined for each species. For future experiments, larger sample size and a new experimental design are recommended.