Spatial variability in responses to environmental conditions in Southern Hemisphere long-finned pilot whales

Hamilton, Vicki; Evans, Karen; Raymond, Ben; Betty, Emma L.; Hindell, Mark A.

doi:10.3354/meps13109

Cited by 3 publications

(3 citation statements)

References 61 publications

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“…Southern hemisphere long-finned pilot whales occur along the southern coastlines of South Africa, South America, New Zealand, and Australia 32 , 33 . Population estimates of long-finned pilot whales in the southern hemisphere do not exist 32 , 34 . The acoustic repertoire of northern hemisphere long-finned pilot whales has been described as highly diverse, repetitive, and physically complex 19 , 35 – 37 .…”

Section: Introductionmentioning

confidence: 99%

Australian long-finned pilot whales (Globicephala melas) emit stereotypical, variable, biphonic, multi-component, and sequenced vocalisations, similar to those recorded in the northern hemisphere

Courts

Erbe

Wellard

et al. 2020

Sci Rep

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While in the northern hemisphere, many studies have been conducted on the vocal repertoire of long-finned pilot whales (Globicephala melas), no such study has been conducted in the southern hemisphere. Presented here, is the first study on the vocalisations of long-finned pilot whales along the southern coast of mainland Australia. Multiple measures were taken of 2028 vocalisations recorded over five years in several locations. These vocalisations included tonal sounds with and without overtones, sounds of burst-pulse character, graded sounds, biphonations, and calls of multiple components. Vocalisations were further categorised based on spectrographic features into 18 contour classes. Altogether, vocalisations ranged from approximately 200 Hz to 25 kHz in fundamental frequency and from 0.03 s to 2.07 s in duration. These measures compared well with those from northern hemisphere pilot whales. Some call types were almost identical to northern hemisphere vocalisations, even though the geographic ranges of the two populations are far apart. Other call types were unique to Australia. Striking similarities with calls of short-finned pilot whales (Globicephala macrorhynchus) and sometimes sympatric killer whales (Orcinus orca) were also found. Theories for call convergence and divergence are discussed.

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Section: Introductionmentioning

confidence: 99%

Australian long-finned pilot whales (Globicephala melas) emit stereotypical, variable, biphonic, multi-component, and sequenced vocalisations, similar to those recorded in the northern hemisphere

Courts

Erbe

Wellard

et al. 2020

Sci Rep

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show abstract

“…In this sense, these splines effectively highlighted the climatic signal of all individuals, retaining the interannual variability and leaving aside noise‐related variance (Cook et al, 1990). Previous studies have also implemented cubic splines in the analysis of GLGs time series in the long‐finned pilot whale ( Globicephala melas ) and sperm whales ( Physeter macrocephalus ) in Australia and New Zealand obtaining satisfactory results (Hamilton & Evans, 2018; Hamilton et al, 2019). However, the EPS and

\overset{r}{true}

values obtained in our study were higher than those reported in previous studies, showing that the common environmental signal has been well represented by the chronologies obtained for South American sea lion of Patagonia.…”

Section: Discussionmentioning

confidence: 99%

“…In this sense, cubic smoothing splines are the most convenient for GLG time series, because they fit more flexibly to them. They also consider autocorrelation in the data and remove different amounts of variance depending on the spline rigidity (Hamilton & Evans, 2018; Hamilton et al, 2019). In this sense, three different cubic smoothing splines of 67%, 50%, and 30% frequency cutoff of the time series length (n) were applied in both sexes.…”

Section: Methodsmentioning

confidence: 99%

Climate anomalies influence tooth growth patterns of South American sea lions

Heredia

Drouville

Srur

et al. 2021

Marine Mammal Science

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El Niño-Southern Oscillation (ENSO) and Southern Annular Mode (SAM) indirectly affect tooth growth of marine mammals, through changes in prey abundance, availability, and composition. This is reflected as variation in the dentine deposition, which determines the formation of annual layers, called growth layer groups (GLGs). The aim of this work was to study potential effects of ENSO and SAM on South American sea lion (Otaria byronia) of Patagonia, by examining interannual variability of GLG width. Adapting dendrochronological techniques, we analyzed 97 individuals (60 females and 37 males) and built six chronologies (three for each sex) by using cubic splines with different rigidity.Chronologies were correlated with MEI (Multivariate ENSO Index) and SAM index time series, considering lags in the biological response. The chronologies of females spanned 39 years and only two of these chronologies showed negative correlation with 1 year lagged SAM events. The chronologies of males spanned 23 years, but none showed significant correlation with these indexes. Our results did not indicate any ENSO effects on this species, while positive SAM events could reduce the abundance or availability of South American sea lion's prey, affecting the nutritional status of females and generating thinner GLGs during the next year.

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Shelf–oceanic dynamics of surface environmental parameters in the Kangaroo Island–Bonney Coast region

Foo

McMahon

Hindell

et al. 2021

Mar. Freshwater Res.

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The shelf and oceanic waters of the Kangaroo Island–Bonney Coast region are important foraging habitats for top marine predators in the ecosystem; however, the dynamics between the two distinct water types have not been investigated. This study examined the spatial and temporal variability of oceanographic parameters in the southern waters of Australia (36–43°S, 136–141°E) associated with the Bonney Upwelling (shelf) and subtropical front (STF; oceanic). Using satellite data from 1997 to 2016, we found that productive oceanic waters were associated with the STF and eddy activity; they were generally furthest from the shelf break in spring–summer (upwelling season on the shelf) and closest to the shelf break in winter–autumn (downwelling season on the shelf). Inter-annual variabilities of chlorophyll-a concentration (Chl-a), sea-surface temperature and sea surface-height anomaly were generally higher in summer than in winter for both shelf and oceanic waters. El Niño–Southern Oscillation, Southern Annular Mode and Indian Ocean Dipole were cross-correlated with anomalous shelf and oceanic Chl-a at various lagged times (range=15–0 months). This study provides a regional perspective of the spatial and temporal oceanographic variability in southern Australian waters, which may help with understanding apex-predator ecology in the ecosystem.

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Spatial variability in responses to environmental conditions in Southern Hemisphere long-finned pilot whales

Cited by 3 publications

References 61 publications

Australian long-finned pilot whales (Globicephala melas) emit stereotypical, variable, biphonic, multi-component, and sequenced vocalisations, similar to those recorded in the northern hemisphere

Australian long-finned pilot whales (Globicephala melas) emit stereotypical, variable, biphonic, multi-component, and sequenced vocalisations, similar to those recorded in the northern hemisphere

Climate anomalies influence tooth growth patterns of South American sea lions

Shelf–oceanic dynamics of surface environmental parameters in the Kangaroo Island–Bonney Coast region

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