Ocean noise contributors in southern resident killer whale habitat

Abstract

The contributions of different marine sectors to underwater noise pollution within endangered Southern Resident killer whale (SRKW) habitat were investigated using a soundscape model for continental shelf waters off British Columbia and Washington State. Inputs to the model included Automatic Identification System (AIS) vessel traffic data, aerial survey estimates of non-AIS traffic, and an extensive database of underwater vessel noise measurements. Model results suggested that roll-on-roll-off ferries had the greatest region-wide contribution to broadband sound pressure level (SPL), followed by container ships, bulk carriers, anchored cargo vessels, and oil tankers. Fishing and recreational vessels had large seasonal contributions in two killer whale masking bands, after accounting for non-AIS vessel presence. Monthly-average SPL from vessels exceeded wind-driven ambient sound by >10 dB throughout most of the study area. These findings highlight the potential impact of vessel activity on acoustic habitat quality for SRKW and other marine animals.