Date of Award

Spring 5-22-2026

Document Type

Thesis: Open Access

Degree Name

MS Marine Science

Department

Environmental and Ocean Sciences

Committee Chair

Ann Bowles

Committee Member

Michael Scott

Committee Member

Rachel Blaser

Abstract

Belugas (Delphinapterus leucas) are known for having wide and complex vocal repertoires. However, the literature on wild belugas has little information on individual repertoires, acquisition of repertoire elements, or usage of elements. The oceanarium setting can make it possible to observe individual vocalizations and communication in several distinct contexts, taking advantage of the interactions among the belugas and the interactions of the belugas with their trainers and caretakers. I focused on vocal imitation and matching in context, i.e., processes that determine repertoire overlap and usage, by studying the individual vocal production in belugas and their interactions with animal care specialists at two managed care facilities, SeaWorld San Diego and Oceanogràfic de Valéncia. I tested 3 hypotheses to address beluga matching and use of the repertoire, as well as the contexts in which they occur. The first addressed the whales communicating in 2 media (in-air and in-water). The second addressed overlaps in individual call repertoire and vocal matching among the whales. The third addressed the potential influence of the trainers’ whistle on beluga whistles. It also addressed the effect of trainer interaction on the belugas’ use of their repertoire.

I collected 3 datasets. The 2022-23 dataset from Wild Arctic in SeaWorld San Diego consisted of in-air recordings collected by a Larson Davis 831C Noise Monitoring System and in-water recordings collected by a SoundTrap ST 300 HF. The 2025 Oceanogràfic de Valéncia dataset consisted of in-air video recordings with an iPhone 12 Pro Max and in-water recordings with 2 SoundTrap ST 300 HFs and 1 SoundTrap ST 400 HF. The 2025 Wild Arctic SeaWorld San Diego dataset consisted of in-air video recordings with an iPhone 15 and in-water recordings with a SoundTrap ST 300 HF.

Results of examining calls in-air vs in-water suggests that the beluga vocal repertoire can vary with social and/or environmental contexts. The relative counts of the calls in-air and in-water for both the 2022-2023 and 2025 datasets were different. Every call type was produced in both media for the 2022-2023 dataset, but some call types were more common in-air and vice versa. For the 2025 dataset, there were more call types that were produced only in-water, meaning for the 2025 dataset there was less overlap of in-air and in-water repertoires.

There was considerable overlap in the individual repertoires (74-100%), even though the whales were not all of the same origin. Maximum frequency was a common feature of the calls that were attributed to individual whales. Based on maximum frequency, of the 5 most common call types of the whales in the 2025 dataset, there was no significant difference for 3 of them.  For the other two, the difference was a small percentage of the maximum. These observations provide evidence of vocal matching.

Before I began my research the bridging whistle seemed to be the most salient human-made sound in the whales’ environment. There was evidence that bottlenose dolphins matched bridging whistles (Richards et al., 1984: Miksis-Olds et al., 2002). I designed an experiment to test the matching of the bridging whistles, but I found no or equivocal evidence of belugas matching the bridging whistle. Instead I found that the whales responded to the whistle and the trainers in the context of training sessions. The whales produced calls and behaviors indicative of strong positive affect – my impression was excitement - upon receiving the trainer's whistle or the whistle combined with vocal praise.

Download

Available for download on Saturday, August 21, 2027

Share

COinS