Are captive-bred cherry salmon with degenerated lateral line systems at a survival disadvantage?

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K06214
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40030:Aquatic bioproduction science-related
• Research Institution: National Museum of Nature and Science, Tokyo
• Principal Investigator: Nakae Masanori 独立行政法人国立科学博物館, 動物研究部, 研究主幹 (30462807)
• Co-Investigator(Kenkyū-buntansha): 長谷川 功 国立研究開発法人水産研究・教育機構, 水産資源研究所(札幌), 主任研究員 (00603325) ; 佐々木 邦夫 高知大学, 教育研究部自然科学系理工学部門, 教授 (10215717)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: サケ科 / 飼育 / 行動実験 / 回避行動 / 成長

Outline of Final Research Achievements

A reduction of neuromasts (sense organ of lateral line system) over the entire body, was examined for the first time in captive-bred (approx. F13) masu salmon Oncorhynchus masou masou. The total number of neuromasts in captive-bred fish was ca. 10% lower than in wild-caught and F1 (offspring of wild parents) fishes, suggesting that the system in captive-bred fish had reduced in number due to domestication. Furthermore, captive-bred masu salmon (approx. F15) tend to high rate of avoidance failure to a falling object under dark conditions than wild and F1 fishes. Growth rates of captive-bred fish (approx. F15) under natural conditions was also lower than those of wild fish. However, these trends were not be correlated with the number of neuromasts, suggesting a strong influence of other factors.

Free Research Field

魚類形態学

Academic Significance and Societal Importance of the Research Achievements

養殖等により何世代にも渡って飼育された魚では，自然環境下での生存率等が野生魚よりも低いことが知られていた．その原因のひとつとして側線系の受容器数の減少が挙げられると考えて検証したが，成長率や暗闇での落下障害物に対する回避の成績が悪化しているものの，側線系の受容器数以外の要素の影響が強いことが示唆された．今後も多様な視点での検証が必要であるが，本データは養殖や希少魚の生息域外保全での飼育の際に役立つ知見となる