Dear colleagues, On behalf of my co-authors, I am pleased to share the publication of two new manuscripts:
Epp, M. V., Fournet, M. E. H., & Davoren, G. K. (2021). Humpback whale call repertoire on a northeastern Newfoundland foraging ground. Marine Mammal Science, 1–18. https://doi.org/10.1111/mms.12859 Abstract: Humpback whales (Megaptera novaeangliae) are a highly vocal baleen whale species with a diverse acoustic repertoire. “Song” has been well studied, while discrete “calls” have been described in a limited number of regions. We aimed to quantitatively describe calls from coastal Newfoundland, Canada, where foraging humpback whales aggregate during the summer. Recordings were made in July–August 2015 and 2016. Extracted calls were assigned to call types using aural/visual (AV) characteristics, and then agreement between quantitative acoustic parameters and qualitative call assignments was assessed using a supervised random forest (RF) analysis. The RF classified calls well (96% agreement) into three broad classes (high frequency (HF), low frequency (LF), pulsed (P)), but agreement for call types within classes was lower (LF: 63%; P: 85%; HF: 81%). We found support for a repertoire of 13 call types based on either high (≥70%) RF agreement (9 call types) or high (≥70%) AV agreement between two observers (4 call types). Five call types (swops, droplets, teepees, growls and whups) were qualitatively similar to call types from other regions. We propose that the variable classification agreement is reflective of the graded nature of humpback whale calls and present a gradation model to demonstrate the suggested continuum. Epp, M. V., Fournet, M. E. H., Silber, G. K., & Davoren, G. K. (2021). Allopatric humpback whales of differing generations share call types between foraging and wintering grounds. Scientific Reports, 11, 16297. https://doi.org/10.1038/s41598-021-95601-7 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. Please contact me ([email protected]<mailto:[email protected]>) for a pdf of the Marine Mammal Science article or with any questions about this work. The Scientific Reports article is open access and is available here: https://www.nature.com/articles/s41598-021-95601-7 -------------------- Mikala Epp, MSc Department of Biological Sciences University of Manitoba
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