Acoustic monitoring of resident, offshore, and transient killer whales off the Washington coast

Abstract

Three acoustically distinct populations of killer whales representing each of the known ecotypes (resident, offshore, transient) were recorded in the Summer–Fall of 2004 off the southern Olympic Coast of Washington. Two high-frequency acoustic recording packages (HARPs) continuously recording at 80-kHz sample rate were deployed to assess the seasonal occurrence of vocal odontocetes in this region. From mid-July to early-October the population-specific discrete calls of killer whales were heard on 8 days and were classified to population by Volker Deecke (UBC) and John Ford (DFO-Canada) using an acoustic ID catalogue. West Coast Transient killer whales producing calls of the California dialect were heard on three occasions from August through October. Offshore killer whales were heard twice in August–September, and Northern Resident killer whales were heard once in August. Although Northern Resident killer whales have been extensively studied within Puget Sound and coastal British Columbia, they have been visually sighted only once off the northern Olympic Peninsula, making their detection at this offshore southerly location unique. Endangered Southern Resident killer whales were not heard at this site from July–October. Analysis of year-round data from a site further offshore is underway. [Funded by Chief of Naval Operations- N45.]