Migration of Mature Chum Salmon along Iwate Prefecture Coast Estimated by Tagging Experiments

Abstract

Tagging experiments were conducted on mature chum salmon Oncoryhnchus keta along the coast of Iwate Prefecture, Japan each fall from 1981 to 1986. Of the 3, 440 individuals tagged, about 38% were recaptured. Tags were recovered from the area extending from off the coast of Chiba Prefecture on the Pacific side of Japan to off the coast of Yamagata Prefecture on the Japan Sea side through the Tsugaru Strait. However, about 97.5% of the fish were recaptured in the coastal waters and rivers of Iwate Prefecture. Distribution of recoveries showed that a large number of the salmon entering northern coastal waters of Iwate Prefecture, and a large part of them migrated to the middle and southern coastal waters of this Prefecture, while only a samll number migrated to the Japan Sea. In addition, only a small return to the coastal waters between Miyagi and Chiba Prefecture were believed to pass through the water front of Iwate Prefecture. The periods between release and recapture and daily movements were also estimated from tag recoveries.