Behavioral patterns of Japanese native common carp in offshore water of Lake Biwa: a bio-logging approach to the study of deep lake fish

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K07545
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: National Institute for Environmental Studies (2017); The University of Tokyo (2015-2016)
• Principal Investigator: Mabuchi Kohji 国立研究開発法人国立環境研究所, 生物・生態系環境研究センター, 主任研究員 (50401295)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 日本在来コイ / 琵琶湖 / バイオロギング

Outline of Final Research Achievements

Native population of common carp (Cyprinus carpio) has been widely endangered in Japan by the introduction of Eurasian strain. However, deep offshore water of Lake Biwa, the largest freshwater body in Japan, contains a relatively pure native population. Why does the native strain of common carp remain only in the Lake Biwa? One of the reasons may be its special adaptations to deep-water life, such as effective swimming in deep water. To confirm the possibility, I examined the swimming behavior of both strains in Lake Biwa using miniature animal-attached accelerometers. The obtained data from 11 fish demonstrated the difference in swimming behavior between the two strains as follows. The native carp frequently moved up and down in the water column without losing neutral buoyancy in shallow water even after coming back from deep water. However, the introduced carp lost its neutral buoyancy once it moved down to about 40 meters: it could hardly swim up from the bottom after that.

Free Research Field

魚類分子生態学