Percussive Behavior in the Southern Resident Killer Whale (Orcinus orca) Population at Lime Kiln Point State Park

Author

Rylee Jensen, Utah State University

Date of Award

5-2019

Degree Type

Thesis

Degree Name

Departmental Honors

Department

Wildland Resources

Abstract

The endangered Southern Resident Killer Whale (Orcinus orca, SRKW) is an iconic species in the Pacific Northwest. Although many ecological aspects of this population have been studied, including population dynamics, genealogy, diet, and habitat-use patterns, why SRKW perform above-surface "percussive" behavior such as breaching, cartwheeling, pectoral fin slapping, tail lobbing, and dorsal fin slapping remains unclear. In the present study, a) individual percussive behavioral data was recorded during the summer of 2016 to evaluate trends by age and sex class, and b) an existing long-term data set on SRKW was analyzed to compare the relationship between the seasonal frequency of percussive behaviors from 1996-2016 and the abundance of Chinook salmon (the primary food source of SRKW) during this time. Over the course of the 2016 season in which SRKW were present in Haro Strait, Washington, USA, we documented 24 encounters involving percussive behavior. We found a significant difference between the rate of percussive behavior performed between ages and sexes, with adult females ranking highest among these groups. We also found a significant relationship between the frequency of percussive behavior and average Chinook salmon catch per unit effort (CPUE) during our study period over the past two decades.

Recommended Citation

Jensen, Rylee, "Percussive Behavior in the Southern Resident Killer Whale (Orcinus orca) Population at Lime Kiln Point State Park" (2019). Undergraduate Honors Capstone Projects. 522.
https://digitalcommons.usu.edu/honors/522