Toxic phytoplankton on the Canadian east coast: Implications for aquaculture

The east coast of Canada is impacted by harmful algal blooms (HAB)-forming phytoplankton that are an impediment to aquaculture and shellfish harvesting in general. Toxic phytoplankton include: 1) paralytic shellfish poison(PSP)-producing Alexandrium fundyense in the Bay of Fundy, and A. tamarense and A. ostenfeldii in the Gulf of St. Lawrence and in Newfoundland; 2) amnesic shellfish poison (ASP; domoic acid)-producing Pseudo-nitzschia multiseries in eastern and northern Prince Edward Island, P. pseudodelicatissima in the Bay of Fundy, and unknown source(s) on the south shore of Nova Scotia, Georges/Browns Banks, and in Newfoundland; and 3) diarrhetic shellfish poison (DSP)-producing Prorocentrum lima, as well as other possible unidentified sources, in southern Nova Scotia, the Bay of Fundy, southern Gulf of St. Lawrence, and eastern Newfoundland. Inexplicably, and fortunately for the shellfish aquaculture industry, all east coast Dinophysis spp. have thus far been found without accompanying DSP toxicity. As a result of research and monitoring efforts aquaculturists have been able to cope, for the most part, with the presence of HABs. The idustry must guard against complacency during the years that HABs appear to be on the decline, because there are long-term cycles in bloom activity and severity. Decreases in federal monitoring of toxic phytoplankton have been offset in part by provincial and industry-funded programs. An increase in partnering is required among federal and provincial agencies, and private industry in order to enhance toxic phytoplankton monitoring and research programs in Canada.