Managing fisheries using genetic data: case studies from four species of Pacific salmon

Pacific salmon exhibit complex patterns of population subdivision and under go substantial marine migrations that result in stock intermixing. Stock as sessment, fishery management, and conservation of salmon are all complicate d by stock multiplicity and intermingling in fishing areas. Genetic data ha ve been successfully used by several agencies in the Pacific Northwest for over a decade to address assessment, management, and conservation needs. Fo ur case studies are described to document the design, implementation, resul ts, and benefits of genetic analysis. These consist of: (1) the chinook sal mon winter gill-net fishery in the lower Columbia River (allozymes), (2) co mmercial pink salmon fisheries in British Columbia (allozymes), (3) chum sa lmon fisheries in Alaska (allozymes, mtDNA, and microsatellites) and, (4) t he recreational coho salmon fishery off Vancouver Island (microsatellite an d MHC genes). Estimates of stock group and/or individual stock contribution s to harvests are obtained using maximum likelihood methods. Simulations in dicate that estimates are often within 5-10% of the true contributions and are quite precise (+/-2-10%) with sample sizes of 100-400. Genetic results have been used both in-season and post-season to determine fishery openings and closures to provide harvest benefits or meet conservation needs, to ad dress catch allocation and equity issues among user groups and between coun tries, to provide data for in-season run-size updates, and to investigate m igration patterns and timing. (C) 1999 Elsevier Science B.V. All rights res erved.