North Pacific Anadromous Fish Commission

Technical Report 17

Table of Contents

Effective Hatchery Releases to Increase Adult Returns of Chum Salmon in the Ishikari River, Hokkaido, Japan

Authors: 
Toshihiko Saito, Kyuji Watanabe, Kentaro Honda, and Tomoki Sato

Abstract Excerpt:
Hatchery practices have a marked effect on the size at, and timing of, ocean entry of hatchery-reared Pacific salmon (Oncorhynchus spp.) (Weitkamp et al. 2015). Because both of these factors play such a crucial role in the early survival and growth of hatchery-reared and wild salmon juveniles during the period of coastal residency (Quinn 2005), hatchery practices have a direct effect on the growth and survival of hatchery-reared fish. The relationship between juvenile releases and adult returns for salmon with otolith thermal marks is expected to provide insights into the causal effects of hatchery practices on differences in salmon survival. To test this hypothesis, the effects of release parameters (e.g., release numbers, release date, and size at release) and the water temperature of the release river (near the release point; hereafter, river water temperature (RWT) and at sea (near the river mouth; hereafter sea surface temperature (SST) on adult returns to the Ishikari River were investigated in chum salmon released with thermal otolith marks.

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DOI:
https://doi.org/10.23849/npafctr17/138.139.

Citation

Saito, T., K. Watanabe, K. Honda, and T. Sato.  2021.  Effective hatchery releases to increase adult returns of chum salmon in the Ishikari River, Hokkaido, Japan.  N. Pac. Anadr. Fish Comm. Tech. Rep. 17: 138–139.  https://doi.org/10.23849/npafctr17/138.139.