More of the same: allopatric humpback whale populations share acoustic repertoire.

Michelle E H Fournet,David K Mellinger,Christine M Gabriele,Lauren Jacobsen,Holger Klinck

doi:10.7717/peerj.5365

Abstract

BackgroundHumpback whales (Megaptera novaeangliae) are a widespread, vocal baleen whale best known for producing song, a complex, repetitive, geographically distinct acoustic signal sung by males, predominantly in a breeding context. Humpback whales worldwide also produce non-song vocalizations (“calls”) throughout their migratory range, some of which are stable across generations.MethodsWe looked for evidence that temporally stable call types are shared by two allopatric humpback whale populations while on their northern hemisphere foraging grounds in order to test the hypothesis that some calls, in strong contrast to song, are innate within the humpback whale acoustic repertoire.ResultsDespite being geographically and genetically distinct populations, humpback whales in Southeast Alaska (North Pacific Ocean) share at least five call types with conspecifics in Massachusetts Bay (North Atlantic Ocean).DiscussionThis study is the first to identify call types shared by allopatric populations, and provides evidence that some call types may be innate.

Highlights

The study of acoustic signaling is a valuable tool for investigating animal behavior across a broad range of taxa (Brockelman & Schilling, 1984; Gannon, 2008; Pijanowski et al, 2011; Clink, Crofoot & Marshall, 2018)
To test the hypothesis that some calls types are inherent to humpback whales, we looked for evidence of shared call types in the call repertoire of two allopatric humpback whale populations on their northern latitude foraging grounds, one in the North Atlantic and one in the North Pacific
A total of 411 sounds fitting the inclusion criteria were classified to one of six known call types; 191 calls were collected across 10 recording days from Massachusetts Bay (MB), and 220 calls were collected across 76 sample days from Southeast Alaska (SEAK; Tables 1 and 3)

Summary

Introduction

The study of acoustic signaling is a valuable tool for investigating animal behavior across a broad range of taxa (Brockelman & Schilling, 1984; Gannon, 2008; Pijanowski et al, 2011; Clink, Crofoot & Marshall, 2018). Within the repertoire of most, if not all, sound-producing vertebrates are a collection of innate (i.e., unlearned) calls that are exercised independently of vocal learning and persist across generations (e.g., Domestic Fowl Gallus gallus and other species in the order Galliformes (Konishi, 1963; Matsunaga & Okanoya, 2009), white-handed gibbons Hylobates lar (Brockelman & Schilling, 1984), New Zealand fur seals Arctocephalus forsteri (Page, Goldsworthy & Hindell, 2001)). We looked for evidence that temporally stable call types are shared by two allopatric humpback whale populations while on their northern hemisphere foraging grounds in order to test the hypothesis that some calls, in strong contrast to song, are innate within the humpback whale acoustic repertoire. This study is the first to identify call types shared by allopatric populations, and provides evidence that some call types may be innate

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