Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)
Date (from‐to) : 2017/04 -2021/03
Author : Ito Motohiro
Capturing juvenile salmon (10-15 cm) migrating in the open ocean after their first year is difficult and has been a black box in the life history of salmon. In this study, we revealed a part of the detailed ecological information of juvenile salmon during the period of high depletion by using fish-eating seabirds as samplers of juvenile salmon.
Otoliths of juvenile salmon collected from seabirds revealed a significant number of thermal signatures that can determine the river of origin, and otolith rings were analyzed to determine the growth rate salmon just after their seaward migration. DNA analysis of salmon muscle samples revealed the source of salmon population, and GPS logger data from seabird identified the locations where the juvenile salmons were foraged; the location of juvenile salmon's distribution during migration. Furthermore, we estimated the amount of juvenile salmon consumed by seabirds, during salmon's first year migration around northern Japan after release.