| Budget Amount *help |
¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2016: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2015: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| 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.
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