A multi-year study of narwhal occurrence in the western Fram Strait—detected via passive acoustic monitoring

Ahonen, Heidi; Stafford, Kathleen M.; Lydersen, Christian; Steur, Laura de; Kovacs, Kit M.

doi:10.33265/polar.v38.3468

Cited by 13 publications

(24 citation statements)

References 57 publications

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“…Furthermore, there is a lack of clarity in signal classification. As we mentioned above, some studies apparently reported click bursts as "pulsed calls" and interpreted them as one of the two main types of communicative sounds (Ahonen et al, 2019;Marcoux et al, 2012).…”

Section: Clicksmentioning

confidence: 96%

“…It is possible that IBF hosts approximately 5% of the total narwhal population west of Greenland (see Heide-Jørgensen et al, 2010;NAMMCO, 2018). Narwhals are recognized as "one of the most vulnerable Arctic species to climate change" due to their narrow ecological niche (Ahonen et al, 2019). Therefore, the potential impacts of the ongoing dramatic warming and the associated changes in the environment around Greenland (including the increased presence of narwhal predators, such as the Arctic killer whale) on the narwhals must be understood (Breed et al, 2017;Koblitz et al, 2016;Laidre et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…It is famous for its unique spiral tusk, which is up to 3 m long and erupts asymmetrically through its upper lip. Narwhals remain an understudied cetacean, despite several hundred years of hunting by the Inuit (or Inughuit) and Europeans (Ahonen et al, 2019;Blackwell et al, 2018;Marcoux, 2008;Marcoux et al, 2012). For example, it was only recently suggested that additionally to the popular theory about the use of narwhal's extraordinary tusk organ in intrasexual selection (e.g., Graham et al, 2020), the tusk could sense changes in salinity, temperature, and pressure (Nweeia et al, 2014), whereas its influence on sound production remains unclear (Ford & Fisher, 1978).…”

Section: Introductionmentioning

confidence: 99%

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Soundscape of a Narwhal Summering Ground in a Glacier Fjord (Inglefield Bredning, Greenland)

Podolskiy

Sugiyama

2020

JGR Oceans

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Narwhal acoustic phonation is embedded in the icy cacophony of one of the noisiest soundscapes in the ocean. The high susceptibility of the narwhal to climate change highlights the need for further efforts to document baseline descriptions of the sounds it produces, especially given the potential anthropogenic impacts on their habitats. However, observations are rare, and narwhal acoustic behavior and habitats are poorly understood (attributed to both the skittish nature of hard-to-approach narwhals and the difficult access to remote and often dangerous glacier fjords). Here, we provide acoustic measurements in a narwhal summering ground in glacial fjords in Northwest Greenland that were mainly collected during Inuit hunting expeditions. This unique observational strategy near a key narwhal hot spot allowed the acquisition of supervised near-source recordings of narwhal vocalizations, which confirms the animal's presence within several hundred meters of an actively calving Bowdoin Glacier. We accurately describe the acoustic signals and noise related to the cetacean, environmental, and anthropogenic sources, show previously unreported signals and their properties, report elevated background noise levels near the calving front, and discuss the general soundscape features of a glacier fjord. The baseline information presented here should encourage long-term follow-up acoustic monitoring in the area and provides an important reference for comparisons with future conditions and other regions. We also anticipate that our work will be a starting point both for the development of criteria to distinguish pulsed calls from terminal buzzes and for a thorough discussion of the dual use of passive acoustic monitoring in traditional hunting practices. Estimates of narwhal numbers in certain areas are essential for general biodiversity assessments and also the Canada/Greenland Joint Commission on the Conservation and Management of Narwhal and Beluga, which

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Section: Clicksmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Soundscape of a Narwhal Summering Ground in a Glacier Fjord (Inglefield Bredning, Greenland)

Podolskiy

Sugiyama

2020

JGR Oceans

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“…However, acoustic studies can be used to increase our knowledge regarding distribution, habitat use, phenology and relative abundance of vocal marine mammal species, as well as facilitating an increased understanding of the relationship of different species with environmental variables and anthropogenic activities (e.g. Moore et al 2012;Stafford et al 2012;Reeves et al 2014;Ahonen et al 2019). Previous studies of the acoustic behaviour of Svalbard's bearded seals have all been conducted in Kongsfjorden (Fig.…”

Section: Introductionmentioning

confidence: 99%

Bearded seal (Erignathus barbatus) vocalizations across seasons and habitat types in Svalbard, Norway

et al. 2021

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Male bearded seals (Erignathus barbatus) use vocal displays to attract females and to compete with other males during the mating season. This makes it possible to monitor breeding populations of this species using passive acoustic monitoring (PAM). This study analysed year-round acoustic data records from AURAL instruments in Svalbard (Norway) to investigate seasonal variation in the acoustic presence of male bearded seals and the phenology of different call types (long, step and sweep trills) at three sites representing a variety of habitats with varied ice conditions. Male bearded seals vocalized for an extended period at a drift-ice site (Atwain; January–July) north of Spitsbergen, while the vocal season was shorter at a High Arctic land-fast-ice site (Rijpfjorden; February–June) and shorter yet again at a west-coast site that has undergone dramatic reductions in sea ice cover over the last 1.5 decades (Kongsfjorden; April–June). Generalized Additive Models showed marked seasonal segregation in the use of different trill types at Atwain, where call rates reached 400 per h, with long trills being the most numerous call type. Modest segregation of trill types was seen at Rijpfjorden, where call rates reached 300 per h, and no segregation occurred in Kongsfjorden (peak call rate 80 per h). Sea ice cover was available throughout the vocal season at Atwain and Rijpfjorden, while at Kongsfjorden peak vocal activity (May–June) occurred after the sea ice disappeared. Ongoing climate warming and sea ice reductions will likely increase the incidence of such mismatches and reduce breeding habitat for bearded seals.

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“…Satellite-tracking studies since the early 1990s indicate that different groups of individuals (termed stocks) show fidelity to different summering grounds, such as fjords, bays or sounds [23,24]. Narwhals in the Barents Sea differ; they rarely come into coastal shelf areas, but rather remain in deep, ice-covered areas year-round [21,25].…”

Section: Introductionmentioning

confidence: 99%

Influence of past climate change on phylogeography and demographic history of narwhals, Monodon monoceros

et al. 2020

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The Arctic is warming at an unprecedented rate, with unknown consequences for endemic fauna. However, Earth has experienced severe climatic oscillations in the past, and understanding how species responded to them might provide insight into their resilience to near-future climatic predictions. Little is known about the responses of Arctic marine mammals to past climatic shifts, but narwhals ( Monodon monoceros ) are considered one of the endemic Arctic species most vulnerable to environmental change. Here, we analyse 121 complete mitochondrial genomes from narwhals sampled across their range and use them in combination with species distribution models to elucidate the influence of past and ongoing climatic shifts on their population structure and demographic history. We find low levels of genetic diversity and limited geographic structuring of genetic clades. We show that narwhals experienced a long-term low effective population size, which increased after the Last Glacial Maximum, when the amount of suitable habitat expanded. Similar post-glacial habitat release has been a key driver of population size expansion of other polar marine predators. Our analyses indicate that habitat availability has been critical to the success of narwhals, raising concerns for their fate in an increasingly warming Arctic.

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A multi-year study of narwhal occurrence in the western Fram Strait—detected via passive acoustic monitoring

Cited by 13 publications

References 57 publications

Soundscape of a Narwhal Summering Ground in a Glacier Fjord (Inglefield Bredning, Greenland)

Soundscape of a Narwhal Summering Ground in a Glacier Fjord (Inglefield Bredning, Greenland)

Bearded seal (Erignathus barbatus) vocalizations across seasons and habitat types in Svalbard, Norway

Influence of past climate change on phylogeography and demographic history of narwhals, Monodon monoceros

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