Underwater noise produced by anthropogenic activities on Vancouver Island, British Columbia

Abstract

In recent decades shipping traffic has been increasing, leading to elevated ambient underwater noise. Extensive research has been conducted on the changes to ambient noise levels of moving ships, but little is known for ships at anchor. Vancouver Island, British Columbia has many anchorage locations where freighters stop prior to entering the Port of Vancouver. Additionally, Vancouver Island has logging activities that occur in estuaries and surrounding waters. These human activities raise concern about what impacts they might be having on the soundscape and marine organisms that inhabit these key locations. Cowichan Bay, BC is an industrialized bay and a key migration corridor for Pacific Salmon (Oncorhynchus spp.). To understand changes to the ambient noise levels in Cowichan Bay, with different anthropogenic activities, seven stationary hydrophones were deployed during Fall 2019 and 2020. Results show substantial changes in the soundscape with both anchored freighters and logging activities for the duration of their presence in the bay, with elevated SPL detected throughout the bay for anchored freighters. Our results demonstrate the impact anchored freighters and logging activities have on underwater soundscapes and are the first step in understanding the impact these activities have on marine organisms and important ecosystems.