Tagging Response and Postspawning Movements of Pacific Herring, a Small Pelagic Forage Fish Sensitive to Handling

Abstract

Pacific Herring Clupea pallasii are an important forage fish in the northern Pacific Ocean and support commercial fisheries throughout the region, although numerous populations have experienced pronounced declines in abundance. Acoustic telemetry can enhance our understanding of the spatial and temporal distribution of depressed herring populations. However, herring are extremely sensitive to handling. During 2012–2013, we tagged 94 adult herring with acoustic transmitters on their spawning grounds in Prince William Sound, Alaska. The handling and tagging methods were specifically designed to minimize physical injuries and stress. Receiver arrays located near the spawning area (2012–2013) and at the principal entrances into the sound from the Gulf of Alaska (2013) were used to track the postspawning movements of the fish. The herring responded well to the tagging procedures. Most were subsequently detected by the arrays, ranging from 88.0% in 2012 to 92.8% in 2013, when the entire tracking system was operational. Forty-three (67.2%) of the 64 fish detected during 2013 were recorded near entrances to the sound, representing minimum travel distances of 50–180 km. Initial movements during the spring and summer were generally to the southwest and mirrored the prevailing currents, but a number of fish were subsequently observed moving east, including one individual detected near the spawning area during the late fall and winter. Larger herring were more frequently detected near the entrances to the sound. Although it is possible that smaller fish exhibit different migratory patterns, the lower detection rate may also suggest that these individuals were adversely affected by the tagging. Our findings suggest that large-scale telemetry studies on pelagic forage fish such as herring are feasible. These data provide new insights into the migratory patterns of herring and present an opportunity to address ongoing questions related to the factors affecting the status and recovery of depressed populations.

Received June 19, 2015; accepted November 24, 2015

ACKNOWLEDGMENTS

Primary funding for this study was provided by the Exxon Valdez Oil Spill Trustee Council. The acoustic receiver arrays at the principal entrances to Prince William Sound were deployed and maintained by the Ocean Tracking Network. We thank B. Reynolds, M. McKinzie, J. Watson, J. Stocking, and S. Lewandoski for their assistance with field work and data analysis and A. Schaefer for preparing maps of the study area. We also thank Captain D. Beam and C. Pape of the MV Montague and Captain D. Janka of the MV Auklet for their support during the tagging cruises, and R. Senkovich for his assistance fabricating the tagging cradle. The paper was critically reviewed by A. K. Gray, J. J. Vollenweider, and W. S. Pegau. The findings and conclusions in the paper are those of the authors and do not necessarily represent the views of the U.S. Government or Prince William Sound Science Center. Reference to trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government or Prince William Sound Science Center.