How acoustics informs understanding of foraging behavior and effects of vessels and noise on killer whales

Abstract

Foraging in toothed whales and dolphins is fundamentally tied to the use of sound. Resident-type killer whales (Orcinus orca) use echolocation to locate and capture fast-moving salmon and other fish prey. In addition to prey availability, disturbance from vessels and noise is a threat to the endangered Southern Resident killer whale population given considerable levels of commercial shipping, fishing, whale-watching and recreational vessel traffic in urban waterways that the whales use for feeding. In this study, we utilized suction cup-attached digital acoustic recording tags (DTAGs) to (1) describe whale acoustic and movement behavior during different phases of foraging that can be differentiated from other behaviors, (2) investigate vessel and noise effects on behavior and foraging outcomes in the endangered population, (3) compare foraging behavior between the endangered population that is struggling with population recovery and another population (Northern Resident killer whales) that is increasing in numbers, and (4) characterize diel patterns of foraging and other behaviors to describe their full activity budget and inform management of vessel traffic and noise during urban expansion along the Pacific Northwest coast of North America. This presentation will highlight results to date and implications for the conservation and management of marine protected species.