Fig. 1. Study site was off the Sanriku coast, Japan, in October 1997 and October 1999. Homing adult chum salmon were fished and released with loggers at the mouth of Otsuchi Bay. Filled squares indicate the sites where salmon were recovered. Unfortunately, the retrieval location of salmon 9902 was unknown. Numbers indicate salmon identification number, and numbers in parentheses correspond to the number of days before salmon were recovered. Lines show 100, 200 and 300 m contours.