Hokkaido National Fisheries Research Institute, 116 Katsurakoi, Kushiro 085-0802, Japan;National Salmon Resources Center, 2-2 Nakanoshima, Toyohira-ku, Sapporo 062-0922, Japan
Abstract:
Estimates of instantaneous mortality rate of mark-recaptured chum salmon Oncorhynchus keta juveniles in coastal waters of the Sea of Japan ranged from 0·033 to 0·268 day−1 in the 14–43 days after release. High mortality rate may have been caused by size-selective mortality or poor ability to adapt to the coastal environment inhabited by chum salmon juveniles soon after release. The results indicated that large-scale mark-recapture experiments are useful for estimating mortality during the early sea life that is considered to be a critical period for Pacific salmon.