Development of a Tool for Acoustic Identification of Killer Whale Communities in the Pacific Ocean

Goal: Create a user-friendly acoustic classifier for killer whale communities found in the northeastern Pacific Ocean.

Time Period: February – November 2015

Our Role: To train and test random forest classifiers for sounds produced by killer whale communities found in the northeastern Pacific Ocean using visually validated acoustic recordings collected during the Pacific Orca Distribution Surveys (PODS) conducted by National Oceanic and Atmospheric Administration (NOAA) Fisheries Northwest Fisheries Science Center (NWFSC).

The northeastern Pacific Ocean is home to three ecotypes of killer whales: residents, transients and offshores. In this area, resident killer whale ecotypes consist of both northern and southern communities. Each community in turn is further organized into pods, which are defined as matrilineal family groups that are regularly observed together. Different killer whale ecotypes, communities and pods exhibit differences in their call repertoires, which include pulsed calls, whistles, and echolocation clicks. Using visually validated recordings made in the presence of four killer whale ecotypes and communities (northern and southern residents, offshores, and west coast transients), Bio-Waves researchers measured variables from pulsed calls, whistles and echolocation clicks and used these to train three random forest classifiers, one for each vocalization-type. Results of the three classifiers were then combined to produce a final classification for each killer whale acoustic encounter. Overall, 80% of encounters were correctly classified using this method. These new classifiers will allow researchers to more effectively and efficiently identify call types to the ecotype or community level and will allow researchers to better characterize the occurrence, range and distribution of killer whales in the northeastern Pacific Ocean.

Collaborators/Partners: Cetos Research Organization, Northwest Fisheries Science Center

Sponsors: SeaWorld & Busch Gardens Conservation Fund

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