Relationship between release sites and return of adult chum salmon to the rivers in the Nemuro Region, eastern Hokkaido
2016
Kasugai, K. (Salmon and Freshwater Fisheries Research Institute, Hokkaido Research Organization, Eniwa, Hokkaido (Japan)) | Sasaki, Y.
The relationships between the release sites of chum salmon Oncorhynchus keta fry and the return of adult salmon to the river was examined by comparing the number of released chum salmon fry from 1984 to 2012 (brood years) and that of returned adult salmon four years after their release in the 11 rivers of the Nemuro Region, eastern Hokkaido, northern Japan, where fry were stocked and adults were captured. A significant positive correlation was observed between mean river return rates and downstream distances in each river-shorter the downstream distance, the lower the river return rate. Moreover, a significant negative correlation between the coefficient of variation for river return rate and downstream distance indicated that these rates might fluctuate considerably in rivers with short downstream distances.
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