Tracking migration of Pacific herring Clupea pallasii in a coastal spawning ground using acoustic telemetry

Pacific herring Clupea pallasii inhabiting around Japan migrate to coastal areas to spawn and are often caught by gill and set nets of coastal fisheries. For sustainable resource management, it is necessary to understand the behavioral patterns of such spawning migration in coastal spawning grounds. In this study, the migration of herring found in the Akkeshi region in eastern Hokkaido was revealed using acoustic telemetry. Individuals showed two movement patterns, viz. migration to Akkeshi Lake and remaining in Akkeshi Bay. For those migrating, most individuals entered the lake within 12-48 h. Two individuals reached the end of the lake within 1-3 days, and herring eggs and individuals in the process of spawning were found there. Consequently, this migration is likely related to spawning in the lake. The timing of migration to the lake appeared to be related to tidal dynamics. For those remaining in the bay, pings were detected at several locations, but none in any area beyond the relatively short period of 1-4 days. It is therefore possible that individuals moved more widely and quickly than the detection range of the receiver and the frequency of the survey in the bay.