Measuring the effectiveness of an acoustic startle device to reduce pinniped predation on salmon

Investigators: Rob Williams (Oceans Initiative) and Vincent Janik (University of St. Andrews)

Declines in marine survival of Salish Sea Chinook, coho, and steelhead have spurred significant research in Washington State over the past five years. Predation by harbor seals on out-migrating juvenile salmon and returning adults has been identified as a major impact on salmon survival. Broad estimates suggest harbor seals can consume large proportions of juvenile Chinook and coho out-migrants and adult returns. Between 1970 and 2015, the annual biomass of Chinook salmon consumed by pinnipeds in Washington State is estimated to have increased from 68 to 625 metric tons.

Harbor seals snack on salmon at the Ballard Locks. Photo provided by Oceans Initiative.

New startle technology has been successful at deterring harbor and grey seals from salmon fish farms in the United Kingdom. In these cases, Acoustic Startle Devices (ASD) are targeted, have fewer environmental side effects, and are less likely to lead to habituation than traditional acoustic deterrent or harassment devices.

This project tests the GenusWave acoustic startle device (ASD) at the Ballard Locks to assess the effectiveness of new deterrent technology in reducing coho, sockeye, and Chinook consumption by harbor seals. If the device is effective at reducing the presence of marine mammals at the Locks, it may then be deployed at other locations in Puget Sound, giving resource managers a sorely needed tool to prevent marine mammals from consuming large numbers of salmon and steelhead at migration bottlenecks.

Ocean’s Initiative staff deploying the ASD at the Ballard Locks. Photo provided by Oceans Initiative.