SYSTEMATICS OF ECONOMICALLY IMPORTANT MARINE-ALGAE - A CANADIAN PERSPECTIVE

Marine algae of economic importance encompass species of positive valu e, such as seaweeds harvested for food or hydrocolloid extractives, an d species with negative effect. such as toxic phytoplankton or nuisanc e macrophytes. Only a small part of the global algal resource is obtai ned in Canada, and the overall benefit to the nation's economy is rela tively minor, but there exists the potential for further development o f useful species. On the other hand, the negative effects of toxic mic roalgae are increasing, in the form of losses to the shellfish fishery and aquaculture industry and the cost of providing toxicity-testing a nd phytoplankton-monitoring services. It is obvious that effective uti lization of valuable algae, or defense against undesirable ones, must be attended by sound taxonomy to ensure that algae of interest are cor rectly identified and recognizable. However, the algae present particu lar problems to systematists, a major one being the variety of life hi stories, which may involve independent and conspicuous dissimilar phas es. In addition, many algae are phenotypically highly variable in resp onse to environment, which is often insufficiently appreciated. The co nverse situation also exists, in that morphologically similar species are sometimes regarded as a single entity. Algal taxonomists should st rive to determine which variations are genetic and therefore taxonomic ally significant. To illustrate these points, we review recent taxonom ic studies on some algal genera of present or potential economic impor tance in Canada.