Improvement of juvenile Pacific salmon production in a regional ecosystem after the 1998 climatic regime shift

• Main Authors: R. J. Beamish, R. M. Sweeting, C. M. Neville
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2004
• Subjects: Fraser River; Pacific; Sockeye; Pink salmon
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.576.7520; http://www.pac.dfo-mpo.gc.ca/science/people-gens/beamish/pdf_files/11.pdf

Abstract.—Beginning in 2000, juvenile Pacific salmon Oncorhynchus spp. in the Strait of Georgia, British Columbia, fed more frequently, contained greater volumes of prey in their stomachs com-pared with the previous 3 years, and increased in size. Abundances in July also increased in 2000 and 2001. Marine survival increased, as indicated by the early marine survival of coho salmon O. kisutch in 2000 and 2001, which improved to more than twice the annual survival estimates for 1997–1999. Other indicators of improved marine survival included exceptional returns of pink salmon O. gorbuscha to the Fraser River in 2001 and sockeye salmon O. nerka in 2002. The change to a more productive regime for juvenile Pacific salmon was a lagged response to an abrupt change in climate in 1998, as shown by regional, basin-scale, and planetary indices. The fishery for Pacific salmon Oncorhynchus spp. in the Pacific Northwest was in the midst of a crisis in the 1990s, as stock abundances declined to such low levels that some stocks were listed as endangered (McElhany et al. 2000). Fisheries were closed or diminished, resulting in devastating eco-