Patterns of Intoxication of Shellfish in the Gulf of Maine Coastal Waters

Abstract
There is considerable variability of intoxication in Mytilus edulis leading to Paralytic Shellfish Poisoning (PSP) along the Gulf of Maine coast. When samples from the same sampling location are collected and analyzed on a sufficiently frequent basis, patterns are evident. The patterns are (1) There are areas of high and low probability of shellfish toxin on the Maine coast. (2) Within the high probability areas, the timing at different stations is similar although there is intraannual variability. (3) Toxin rise can occur any time during vernal warning, the most probable timing being spring or late summer. (4) Toxin levels at offshore stations (e.g. Monhegan Island) are frequently much higher than toxin levels at nearshore and inshore stations. These patterns are useful as tracers of bloom dynamics.Key words: Paralytic Shellfish Poisoning, PSP; shellfish toxins, dinoflagellates, bloom dynamics, red tide, Gonyaulax tamarensis var. excavata, Mytilus edulis