North Pacific Anadromous Fish Commission

Technical Report 23

Table of Contents

Production Trend of Hokkaido Chum Salmon Estimated by Multivariable Models Incorporating Environmental Factors and Biological Interactions in the North Pacific Ocean

Authors:
Masahide Kaeriyama, Irene D. Alabia, and Shigehiko Urawa

Abstract Excerpt:
Global warming continues unabated. The global annual mean of sea surface temperature (SST) is increasing at a rate of 0.6ºC per century, and was the highest on record in 2023. SST in the North Pacific Ocean has warmed by about 1ºC over the past 120 years. Pacific salmon (Oncorhynchus spp.) play an important role as a keystone species and provider of ecosystem services in North Pacific ecosystems. Their total catch has shown an increasing trend since the late 1970s. However, in this century, the abundance of Pacific salmon has decreased in southern areas and increased in northern areas due to the effects of global warming. In particular, the abundance of Hokkaido chum salmon (O. keta) has decreased since the 2000s (Kaeriyama 2023). On the other hand, in the Bering Sea, the marked increase in pink salmon abundance has negatively impacted trophic cascades through the top-down effect by reducing herbivorous zooplankton abundance sufficiently to increase phytoplankton densities (Ruggerone et al. 2023) and low growth of sockeye salmon (O. nerka) (Rand and Ruggerone 2024). Japanese chum salmon are a southernmost population, and they migrate widely, inhabiting different ecosystems in the North Pacific and adjacent seas, depending on their life stage and season (Urawa et al. 2018). This complicated life history makes it difficult to understand the mechanisms of their population dynamics. The objective of this study is to discuss how the marine life history of Hokkaido chum salmon is affected by marine environmental factors such as inter- and intraspecific interactions among Pacific salmon, SST, and zooplankton biomass using various models, and to predict their future production trends.

*This is the first paragraph of an extended abstract. Download the full abstract below.

DOI:
https://doi.org/10.23849/npafctr23/4bb8ty

Citation

Kaeriyama, M., I.D. Alabia, and S. Urawa.  2024. Production trend of Hokkaido chum salmon estimated by multivariable models incorporating environmental factors and biological interactions in the North Pacific Ocean.  N. Pac. Anadr. Fish Comm. Tech. Rep. 23: 34–39.  https://doi.org/10.23849/npafctr23/4bb8ty