Allopatric humpback whales of differing generations share call types between foraging and wintering grounds

Abstract Humpback whales (Megaptera novaeangliae) are a cosmopolitan baleen whale species with geographically isolated lineages. Despite last sharing an ancestor ~ 2–3 million years ago, Atlantic and Pacific foraging populations share five call types. Whether these call types are also shared between...

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Bibliographic Details
Published in:Scientific Reports
Main Authors: Mikala V. Epp, Michelle E. H. Fournet, Gregory K. Silber, Gail K. Davoren
Format: Article in Journal/Newspaper
Language:English
Published: Nature Portfolio 2021
Subjects:
Medicine
R
Science
Q
Pacific
baleen whale
Megaptera novaeangliae
Newfoundland
Online Access:https://doi.org/10.1038/s41598-021-95601-7
https://doaj.org/article/3dba6c81af7149d3ace03c0c279a065f
Description
Summary:Abstract Humpback whales (Megaptera novaeangliae) are a cosmopolitan baleen whale species with geographically isolated lineages. Despite last sharing an ancestor ~ 2–3 million years ago, Atlantic and Pacific foraging populations share five call types. Whether these call types are also shared between allopatric breeding and foraging populations is unclear, but would provide further evidence that some call types are ubiquitous and fixed. We investigated whether these five call types were present on a contemporary foraging ground (Newfoundland, 2015–2016) and a historic breeding ground (Hawaii, 1981–1982). Calls were classified using aural/visual (AV) characteristics; 16 relevant acoustic variables were measured and a Principal Component Analysis (PCA) was used to examine within-call and between-population variation. To assess whether between-population variation influenced classification, all 16 variables were included in classification and regression tree (CART) and random forest analyses (RF). All five call types were identified in both populations. Between-population variation in combined acoustic variables (PC1, PC2, PC3) was lower within call types than among call types, and high agreement between AV and quantitative classification (CART: 83% agreement; RF: 77% agreement) suggested that acoustic characteristics were more similar within than among call types. Findings indicate that these five call types are shared across allopatric populations, generations, and behavioural contexts.

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