| Budget Amount *help |
¥16,640,000 (Direct Cost: ¥12,800,000、Indirect Cost: ¥3,840,000)
Fiscal Year 2014: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
Fiscal Year 2013: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2012: ¥12,220,000 (Direct Cost: ¥9,400,000、Indirect Cost: ¥2,820,000)
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| Outline of Final Research Achievements |
Otolith chemical composition of juvenile chum salmon was found to well discriminate the juveniles from different hatcheries within the same area. The analysis through the life history for adult from Hokkaido coast and immature fish from the Bering Sea revealed that otolith Sr:Ba ratios periodically fluctuated. These suggest that otolith chemical analysis can provide important information to reveal the effects of the 2011 Tsunami of the Great East Japan Earthquake on the migration history and homing behavior.
The upstream migrants of ayu immediately after the tsunami were found to be solely composed of fish hatched during October-November, whereas those before the tsunami were mostly composed of fish hatched in September. The shift of hatch dates was found to result of the selective mortality of early hatched fish occurred during the tsunami. The hatch date composition of upstream migrants returned to the state before the tsunami in 2013-2014, but the sizes were observed to decrease.
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