Figure 2. 1988 Shellfish toxicities in mussels from stations representative of the Alexandrium. habitats. Toxicity is first reported either in southern salt ponds and embayments (e.g.Hemenway) or in the western GOM, (Lumbo's Hole in Casco Bay), followed by northern Massachusetts (Annisquam) and Massachusetts Bay (Cohasset). The rapid increase in toxicity at Cohasset suggests delivery of established populations from the WMCC, rather than in situ growth. Later in the bloom season, toxicity peaks in the EMCC region (e.g.Gleason Cove), with no subsequent toxicity observed "downstream" to the west, either in the PSP "sandwich" in Penobscot Bay (Spruce Head) or at WMCC stations. (Note scale changes on several figures). Modified from Franks (1990).