Our aim was to describe the migratory process of pink salmon Oncorhynchus gorbuscha and to examine the relationship between the migration and physical environments (sea surface temperature and day-length). From tag data for 4,876 individuals for the past thirty years, we examined distribution change, migratory speed and day-length during open sea migration. The open sea distribution was consistent with 4-11 $,^{irc} sea surface waters as found by past studies. Mean migratory speed was 31.5$pm/tmp/tmp.AXqGzx2hAF7.8km/day. Migratory speed was significantly correlated with day-length, and pink salmon tended to migrate fast around the summer solstice. This result suggests that the photoperiod is an important factor related to the spawning migration of pink salmon.

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https://www.jstage.jst.go.jp/article/suisan1932/61/2/61_2_137/_article/-char/ja/