Guidelines for the Culture of Fish Stocks for Resource Management

Abstract

Examples of desired genetic changes produced in fish by selective breeding are contrasted with those of unintentional and often harmful genetic changes resulting from artificial propagation over prolonged periods, e.g. reduced longevity and reduced temperature tolerance. Evidence for undesired effects caused by the hatchery environment on captive fish stocks is also presented, e.g. precocity, inappropriate feeding behavior, and the risks posed by artificial rearing techniques are discussed. Methods for identifying both genetic and environmentally induced changes are outlined along with experimental designs for distinguishing between them. Some practical recommendations are offered for establishing, developing, and maintaining brood stocks in hatcheries and for managing wild fish populations in ways that maximize genetic variability while avoiding the occurrence of undesirable changes. Adherence to the recommended procedures will improve progress in fisheries rehabilitation efforts.Key words: fish culture, genetics, environmental effects, brood stocks, resource management