The use of low-grade heat in cold climates for aquaculture: a perspective in the western hemisphere and Japan

The present demonstrable use of heated effluents from thermal generating stations for the culture of finfish, shellfish and seaweeds is reviewed in the United States and Japan. Studies in Canada are summarized. An examination of the relationship between the species selected for study and the operating regimes of the plants, in terms of optimum growing temperatures and discharge temperatures, indicates that maximum utilization of available heat will not be achieved. A strategy to improve heat utilization is presented involving the use of exotic species during warm seasons as part of a multicrop system to more fully exploit discharge temperatures. The following criteria for species selection are proposed: (1) all stages of its life history must be absolutely controllable; (2) potential diseases and parasites must be known and be treatable; (3) a market opportunity must be identified; (4) realizable return must justify investment. A list of some 10 suitable species is presented. Site criteria are also given, as follows: (1) plant must be multi-unit; (2) plant must be a system base-load operation. The future of aquaculture in Canada is examined. (author)