騒音環境で育ったサケは回帰率が低下することを実証(Quiet, please: Hatchery salmon raised amid noise are less likely to return to spawn)

2026-07-08 ワシントン州立大学(WSU)

ワシントン州立大学(WSU)の研究チームは、ふ化場で飼育されるサケが人工的な騒音にさらされると、放流後に生まれた川へ回帰して産卵する割合が低下することを明らかにした。研究では、ポンプや機械設備の稼働音を模した騒音環境と静かな環境でサケを飼育し、その後に放流して回帰率を比較した。その結果、騒音下で育ったサケは静かな環境で育った個体に比べて回帰率が有意に低く、生存や繁殖成功に悪影響を受けることが判明した。一方、成長速度や外見には大きな違いがみられず、騒音の影響は通常の飼育管理では把握しにくいことも示された。研究チームは、慢性的な騒音がストレス反応や感覚機能、回遊行動の形成に影響を与えた可能性を指摘している。この成果は、ふ化場における騒音管理がサケ資源の回復や放流事業の成功率向上に重要であることを示すものであり、水産資源管理や生態系保全に新たな改善策を提供する知見となる。

<関連情報>

孵化場で飼育されたキングサーモンの発育、行動、および回帰率に対する騒音の影響の評価 Evaluating the effect of noise on the development, behavior, and return rates in hatchery-reared Chinook Salmon

Rikeem K Sholes,Teyline McLean,Alexandra Pederson,Susannah Schloss,Olivia Molano,Jonah Piovia-Scott,Allison B Coffin
North American Journal of Fisheries Management  Published:08 June 2026
DOI:https://doi.org/10.1093/najfmt/vqag023

騒音環境で育ったサケは回帰率が低下することを実証(Quiet, please: Hatchery salmon raised amid noise are less likely to return to spawn)

Abstract

Objective
The National Fish Hatchery System’s role in supplementing declining fish populations is critical to achieve U.S. conservation objectives. However, hatchery-reared fish often exhibit lower fitness and survival compared with their wild counterparts. This difference is potentially due to environmental factors that are unique to hatchery environments. We sought to understand the relationship between hatchery-derived noise and early rearing habitat on the development, sensory physiology, swim performance, and survival of Chinook Salmon Oncorhynchus tshawytscha.

Methods
Before first feeding, juvenile Chinook Salmon were reared in two different rearing habitats (Heath trays and Redd Boxes). After feeding began, fry were transferred to enclosures with one of three noise conditions: quiet (noise abated), ambient hatchery noise, and continuous white noise treatment (150 dB [referenced to 1 μPa]). During each month (February–April), we analyzed growth metrics, brain-to-body-weight ratios, lateral line neuromast number, and inner ear cell counts. In April (prerelease), we also analyzed swimming performance and then tagged and released fish to quantify adult return rates.

Results
We observed moderate differences in fish length in April, shortly before fish were released. Neither sensory development nor swimming behavior was substantially impacted by rearing environment or noise exposure. However, we saw significant differences in return rates between noise treatment groups. We found that fry exposed to continuous white noise were significantly less likely to return to the hatchery, whereas fish in the quiet and ambient noise treatments had higher return rates.

Conclusions
Our findings indicate that chronic high-intensity noise exposure in hatcheries can negatively affect return rates of hatchery-reared Chinook Salmon, highlighting the importance of soundscape management to optimize fish fitness.

1401漁業及び増養殖
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