Pacific Salmon Hatcheries in British Columbia

—Of the many technologies used by the Canadian Salmonid Enhancement Program (SEP, established in 1979), hatcheries have been a major tool used to increase the freshwater survival of selected wild, native stocks of coho salmon Oncorhynchus kisutch, Chinook salmon O. tshawytscha, and chum salmon O. keta, both to address conservation concerns and to provide fishing opportunities. Salmonid Enhancement Program hatcheries have contributed substantially to the fisheries for coho and chum salmon, and less so to the fisheries for Chinook salmon. Although hatcheries have successfully provided high survival environments in freshwater, once released, artificially propagated fish are subject to the same environmental constraints and high mortality rates as are naturally propagated fish. Wild fish from both these components of coho and Chinook salmon stocks encountered substantially lower marine survival in the 1990s compared to the 1980s. Salmonid Enhancement Program tag studies show that marine survivals of hatchery salmon stocks have also been extremely variable, in spite of fairly consistent smolt release strategies. The approach taken by SEP to fully integrate hatchery and naturally produced components of endemic wild stocks of Pacific salmon, in conjunction with improvements in habitat and harvest management, should maximize long-term stock viability in Canada. 1 E-mail: mackinlayd@pac.dfo-mpo.gc. ca Background British Columbia has a large landmass (950,000 km) with a small human population (~4 million) that is concentrated in a few urban centers (85% urban), partly because the province is extremely mountainous (75% is more than 1,000 m in elevation; Cannings and Cannings 1996). The tiny amount of flat, arable land (98.5% of the land area has moderate or severe restrictions for agriculture; McGillivray 2000) makes renewable natural resource extraction, including fisheries, especially important for economic activity in the province. There are almost 10,000 spawning populations that have been identified as stocks of Pacific salmon in British Columbia, with stock sizes ranging from a few fish to several million (Slaney et al. 1996). Because the province’s topography is dominated by a mountainous landscape with narrow valleys, almost all human activities have major effects on salmon freshwater habitat. These impacts can only increase as the population of the region increases in the future (Lackey 2003). Fish culture has a long history in the management of Pacific salmon stocks in Canada. Early hatchery programs (1894–1938) concentrated on sockeye salmon Oncorhynchus nerka and involved collecting and hatching hundreds of millions of eggs to make up for the combination of destruction of freshwater spawning habitat brought on by gold mining and logging, and high exploitation rates in the commercial fishery. The large hatchery programs of the early 1900s involved planting eyed sockeye eggs or sac-fry into lakes and resulted in only minor demonstrable improvements to natural production (Foerster 1968). This fairly ineffective technique could not make up for the resource extraction of the industrial fishery, and under funding pressure during the Great Depression of the 1930s, all Canadian Pacific salmon hatcheries were shut down by 1938 (Roos 1991). In 1974, Peter Larkin, one of the deans of Canadian fisheries science, wrote an essay that reaffirmed the biological, economic and social justification of improving the freshwater survival of salmon through a variety of “enhancement” measures and recommended the formation of an agency with “the single responsibility of salmon enhancement” (Larkin 1974). Larkin assumed that the high historical abundance of salmon