Annual calf indices for beluga whales, Delphinapterus leucas, in Cook Inlet Alaska, 2006-12

Hobbs, Roderick C.; Sims, Christy L.; Shelden, Kim E. W.; Brattström, Linda Vate; Rugh, David J.

doi:10.7755/mfr.77.2.3

Cited by 12 publications

(18 citation statements)

References 8 publications

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“…Hobbs et al () analyzed the stomach contents of 21 Cook Inlet beluga whales collected between April and November 1995–2007 and found that eulachon and, to a lesser extent, gadids ( Gadidae sp.) were the most abundant fish prey species during the early spring (Apr–May/Jun), and Pacific salmon were dominant in whale diets during late spring and summer (Jul–Sep).…”

Section: Discussionmentioning

confidence: 99%

“…Cook Inlet beluga spatiotemporal distributions are believed to be influenced by prey distributions (e.g., Hobbs et al , Ashford et al ). We divided aerial survey data into 5 6‐week‐long seasons based upon the general timing of prey field availability in Upper Cook Inlet, such that Seasons 1–4 were characterized by dominant prey fields (i.e., eulachon [ Thaleichthys pacificus ] in Seasons 1 and 2, salmon [ Oncorhynchus spp.]…”

Section: Methodsmentioning

confidence: 99%

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High‐frequency aerial surveys inform the seasonal distribution of Cook Inlet beluga whales

et al. 2018

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Management options to mitigate potential effects from the overlap of anthropogenic and marine mammal activities require understanding of species' habitat use and movement patterns. We analyzed high temporal frequency industrial marine mammal monitoring program aerial surveys conducted over a protracted period from April to October of 2013 and 2014 to examine beluga whale (Delphinapterus leucas) ecology in the Cook Inlet, Alaska, USA. Our objectives were to characterize the spatiotemporal whale distributions, determine the utility of these patterns to inform management practices, and assess industrial survey data as a supplement to agency population monitoring programs. Cook Inlet beluga whale densities peaked in late June to early July, with some activity observed in all survey months. Consistent trends in spatial persistence were identified and found to be associated with the seasonal sequence of prey field distributions including eulachon (Thaleichthys pacificus), Pacific salmon (Oncorhynchus spp.), and gadids (Gadidae spp.). Seasonal beluga whale distributions were stable across both study years, indicating hotspots of habitat use with predictable seasonal timing. The regular temporal and spatial distribution of beluga whale activity suggests potential to inform management efforts to mitigate disturbance of whales from anthropogenic activities in the Inlet. We found high-frequency surveys conducted as part of industrial marine mammal monitoring programs provided a useful additional data source for population monitoring; however, improvements in survey design and efforts to control for observer detection biases may further increase the utility of these surveys to complement ongoing standardized scientific surveys. Ó

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

High‐frequency aerial surveys inform the seasonal distribution of Cook Inlet beluga whales

et al. 2018

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“…mating might occur anywhere throughout their range). Similar to Arctic beluga populations, CIBW calving is believed to occur in early summer (Hobbs et al, 2015a) although Native hunters have observed newborn CIBW calves from April through August (Huntington, 2000).…”

Section: Introductionmentioning

confidence: 99%

Socio-sexual and probable mating behavior of Cook Inlet beluga whales, Delphinapterus leucas, observed from an aircraft

Lomac-MacNair¹,

Smultea²,

Cotter³

et al. 2016

MFR

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“…Based on traditional ecological knowledge of Native beluga hunters, Cook Inlet belugas calve from April to August (Huntington ) and calf surveys are conducted in Cook Inlet in August based on the expectation that calves will be 2 mo of age or younger at this time (Hobbs et al . ). During our defined summer season (July–September) CIB calves should be only a few months old suggesting they will be emitting mostly pulsed calls.…”

Section: Discussionmentioning

confidence: 97%

“…Captive-born beluga calves have produced pulsed calls exclusively through the first weeks of life (Vergara and Barrett-Lennard 2008, Manuel Castellote 2 ) and produced more pulsed calls than any other call category during the first 7 mo of life (Vergara and Barrett-Lennard 2008). Based on traditional ecological knowledge of Native beluga hunters, Cook Inlet belugas calve from April to August (Huntington 2000) and calf surveys are conducted in Cook Inlet in August based on the expectation that calves will be 2 mo of age or younger at this time (Hobbs et al 2012). During our defined summer season (July-September) CIB calves should be only a few months old suggesting they will be emitting mostly pulsed calls.…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal patterns in the calling behavior of beluga whales, Delphinapterus leucas, in Cook Inlet, Alaska

Blevins‐Manhard

Atkinson

Lammers

2016

Marine Mammal Science

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Cook Inlet beluga whales (CIBs) are an endangered population residing in Cook Inlet, Alaska. We characterized the calling behavior of CIBs to improve our understanding of sounds produced by this population. Bottom‐moored hydrophones were deployed at Eagle Bay in summer 2009 and at Trading Bay in summer and winter 2009. CIB sounds were qualitatively analyzed and categorized as a whistle, pulsed call, or click train. A total of 4,097 calls were analyzed, and 66 unique whistle contours were identified. Whistles were quantitatively analyzed using a custom Matlab program. A chi‐square test showed the call category usage at Eagle Bay during summer 2009 and those at Trading Bay during summer 2009 and winter 2009–2010 differed significantly (P < 0.001). Pulsed calls were more common during summer months, and click trains within the frequency band (12.5 kHz) were more common in Eagle Bay. The variation in calling behavior suggests differences in habitat usage or in the surrounding environment, including background noise. With the proposed development projects in Cook Inlet and the potential increase in ambient noise level due to ocean acidification, it is important to understand how this endangered population uses sound, and what anthropogenic factors may influence that use.

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Annual calf indices for beluga whales, Delphinapterus leucas, in Cook Inlet Alaska, 2006-12

Cited by 12 publications

References 8 publications

High‐frequency aerial surveys inform the seasonal distribution of Cook Inlet beluga whales

High‐frequency aerial surveys inform the seasonal distribution of Cook Inlet beluga whales

Socio-sexual and probable mating behavior of Cook Inlet beluga whales, Delphinapterus leucas, observed from an aircraft

Spatial and temporal patterns in the calling behavior of beluga whales, Delphinapterus leucas, in Cook Inlet, Alaska

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