Genetics in fisheries management

Genetic analyses have much to offer fisheries managers, especially in the provision of tools enabling unequivocal specimen identification and assessment of stock structure. The three commonly-used genetic tools - allozymes, mitochondrial DNA and microsatellites - differ in their properties. These differences must be born in mind, especially when interpreting gene frequency data collected for stock structure research. Examples where genetic approaches have been used to identify specimens are given, with special attention being given to compliance and labelling issues. Treatment of stock structure focuses on Atlantic cod and on yellowfin, bigeye and albacore tunas. The different resolving powers of the various techniques are discussed. Marine fish typically show low levels of population genetic differentiation, and in such species the use of large sample sizes and, preferably, multiple types of markers are desirable to resolve stock structure issues.