Evaluation of carrying capacity of pacific salmon in the North Pacific Ocean for ecosystem — Based Sustainable Conservation Management

• Main Author: Masahide Kaeriyama
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Climate change; carrying capacity; hatchery/wild interactions; Keta; Pacific; Sockeye; aleutian low; Pink salmon
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.517.2856; http://www.npafc.org/new/publications/Technical Report/TR5/page 1-4(Kaeriyama).pdf

The change in biomass of Pacific salmon (Oncorhynchus spp.) indicates a 30- or 40-year periodicity in the North Pacific Ocean coinciding with long-term climate conditions. I estimated the carrying capacity (K) of sockeye (O. nerka), chum (O. keta), and pink salmon (O. gorbuscha) in the North Pacific Ocean using the replacement level of the Ricker’s recruitment curve, and defined residual carrying capacity (RCC): RCC = (Carrying capacity – Biomass) / (Carrying capacity) x 100 A significant positive correlation between the Aleutian low pressure index (ALPI) and the carrying capacity was observed at the species level. Factors affecting carrying capacity at the population level, such as reproductive regimes (e.g. survival rate and sea surface temperature (SST) in the early marine life period and hatchery technology), differed by population in Hokkaido chum salmon. The RCC was significantly positively correlated with body size and negatively related to age at maturity in Hokkaido chum salmon populations. The biomass of chum salmon wild populations in the 1990s decreased 50 % below that of the 1930s, despite the significant increases in the biomass of hatchery populations. Biological interaction between wild and hatchery populations should be an important consideration in the sustainable management of Pacific salmon production based at the ecosystem level. In the North Pacific Ocean, the annual catch of Pacific salmon increased from the late 1970s to the early 1990s due to favorable oceanic conditions associated with long-term climate change and successful hatchery programs