| Budget Amount *help |
¥3,380,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥780,000)
Fiscal Year 2012: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2011: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2010: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Research Abstract |
Chum salmon population in Iwate prefecture has declined in catch for these years, although the numbers of juvenile release remained constant. To elucidate the cause of such decrease, stable isotope ratios of fish scales of chum salmon were measured. As results, carbon and nitrogen stable isotope ratiosof muscle and marginal parts of fish scales are positively correlated. This finding suggested fish scales remain stable isotopic signature of pray items. The carbon and nitrogen stable isotopic signatures of second year in oceanic life stage were lower for both Iwate and Hokkaido populations. This finding suggested Japanese chum salmon might have depended on lower level of food web as food items at relatively early stage in its life history.
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