Mechanism of outbreak in bacterial cold-water disease of ayu (Plecoglossus altivelis): an approach based on research of the life history

2015 Fiscal Year Final Research Report

• Project/Area Number: 25450283
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: Nihon University
• Principal Investigator: TAKAI Noriyuki 日本大学, 生物資源科学部, 准教授 (00350033)
• Co-Investigator(Kenkyū-buntansha): MANO Nobuhiro 日本大学, 生物資源科学部, 准教授 (10339286) ; KUWAE Tomohiro 国立研究開発法人港湾空港技術研究所, その他部局, チームリーダー (40359229)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: アユ / 冷水病 / 種苗放流 / 餌環境 / 安定同位体 / 多摩川

Outline of Final Research Achievements

Inspection of bacterial cold-water disease and research of the life history were performed for ayu (Plecoglossus altivelis) in the Tama River watershed, Japan, in order to examine the causal relationship between the temporal changes in the environment and the outbreak of the cold-water disease in ayu, accompanied with the opening of the fishing season. Pathogenic bacteria were frequently detected in seed-production ayu reared for the release in the river, suggesting that the seed-production ayu was likely a main source of infection in the study area. The outbreak of the disease was found in the caught ayu, which was identified as seed-production fish just after the release in the river by analyzing carbon and nitrogen stable isotope ratios. This result suggests that the stress with the release rapidly developed the disease of the seed-production ayu.

Free Research Field

生態学