​​A Description of the Song Unit Repertoire and Rate of Change of Southeastern Pacific Humpback Whales at Their Breeding Area in the Gulf of Chiriquí, Panama

• Main Author: Oppenheimer, Franny
• Format: Text
• Language: unknown
• Published: UVM ScholarWorks 2024
• Subjects: Bioacoustics; Whale Song; Cetaceans; Marine Biology; Population Ecology; College of Arts and Science Honors; Pacific; Humpback Whale; Megaptera novaeangliae
• Online Access: https://scholarworks.uvm.edu/castheses/141; https://scholarworks.uvm.edu/context/castheses/article/1159/viewcontent/Oppenheimer_Manuscript.pdf

Male humpback whales (Megaptera novaeangliae) are known to produce long and complex songs during their breeding season. Every year, each humpback whale breeding population around the world sings a unique song, which can vary slightly or rapidly from that of the previous year. The degree of difference in a population’s song from year-to-year depends on the level of connectivity with other humpback whale populations. In this study, I use novel methods of classification and calculation to describe the repertoire of units that make up the song of Southeastern Pacific humpback whales, also known as the Breeding Stock G (BSG) at their breeding area in Gulf of Chiriquí, Panama from 2007 to 2023. The unit repertoire of BSG whales consisted of a total 47 distinct unit types. Most unit types had a peak frequency below 5 kHz and a duration greater than 1sec. The most used units were those with a flat and tonal contour, and dense presence of harmonics. The composition of new, constant, and recalled units varied within and between year periods. However, in most periods, the song was primarily composed of constant (used in two consecutive years) and recalled units (seen in previous years but not the year directly before), indicating a slow pace of change until recent years. We see that the pace of change is generally driven by gradually phasing out units, but that at least two instances a change was driven by the addition of new units, causing a relatively rapid change in the song that suggests an instance of song ‘revolution’. This study provides the first unit repertoire analysis for this humpback whale population and supports the hypothesis that changes in song unit composition are generally gradual, with a few instances of relatively rapid change, which suggest the arrival of males from other breeding populations at either their breeding or feeding areas. Ultimately, the continuing long-term monitoring of the songs of this population will help us to understand the potential effects of climate change and human ...