Over the last 60 years, human-generated noise, specifically from shipping traffic, has led to concern about its effects on marine species. In the northeast Pacific, two important species are declining: orcas and Chinook salmon. Research shows that orcas demonstrate changes in their behaviour and vocalizations in the presence of ships. However, until recently, little was known about the impacts of shipping on their primary prey—Chinook salmon.

Researchers are monitoring acoustically tagged salmon in the Strait of Georgia and a passive array of 10 hydrophones in Cowichan Bay, British Columbia, to collect data on encounters based on shipping noise and whale vocalizations. An underwater hydrophone was deployed to collect noise occurring in the environment. This information is synced with data from tagged salmon to compare behaviour before, during and after each encounter.

This research is an important step toward understanding impacts and filling knowledge gaps on how salmon respond to shipping traffic and avoid predation.