DYNAMIC MODELING OF PHYCOTOXIN KINETICS IN THE BLUE MUSSEL, MYTILUS-EDULIS, WITH IMPLICATIONS FOR OTHER MARINE-INVERTEBRATES

Modelling the uptake and detoxification kinetics of phycotoxins in mar ine filter-feeding bivalve molluscs is discussed and illustrated by a case study involving blue mussels (Mytilus edulis) in the lower St. La wrence estuary in eastern Canada. A dynamic model was fit to empirical data acquired on differential responses of mussels transplanted from sites characterized by differing history of exposure to toxigenic bloo ms responsible for paralytic shellfish poisoning (PSP). Although it is difficult to collect sufficient data to calibrate complicated models, it appears that one- and two-compartment models are fully adequate fo r this type of modelling. Measuring phycotoxin levels in shellfish can be a useful and cost-effective adjunct to direct monitoring of phytop lankton toxicity in the water column, because ongoing filtration by sh ellfish provides an integrated estimate of the toxin to which they are exposed.