Zones of impact around icebreakers affecting beluga whales in the Beaufort Sea

2000 ◽  
Vol 108 (3) ◽  
pp. 1332 ◽  
Author(s):  
Christine Erbe ◽  
David M. Farmer
Keyword(s):  
Beaufort Sea ◽  
Beluga Whales

scholarly journals Year-Round Dive Characteristics of Male Beluga Whales From the Eastern Beaufort Sea Population Indicate Seasonal Shifts in Foraging Strategies

2022 ◽  
Vol 8 ◽  
Author(s):  
Luke Storrie ◽  
Nigel E. Hussey ◽  
Shannon A. MacPhee ◽  
Greg O’Corry-Crowe ◽  
John Iacozza ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Environmental Variables ◽  
Marine Mammals ◽  
Beaufort Sea ◽  
Optimal Foraging Theory ◽  
Sampling Interval ◽  
Foraging Strategies ◽  
Vertical Movements ◽  
Beluga Whales ◽  
Seasonal Shifts

Dive behavior represents multiple ecological functions for marine mammals, but our understanding of dive characteristics is typically limited by the resolution or longevity of tagging studies. Knowledge on the time-depth structures of dives can provide insight into the behaviors represented by vertical movements; furthering our understanding of the ecological importance of habitats occupied, seasonal shifts in activity, and the energetic consequences of targeting prey at a given depth. Given our incomplete understanding of Eastern Beaufort Sea (EBS) beluga whale behavior over an annual cycle, we aimed to characterize dives made by belugas, with a focus on analyzing shifts in foraging strategies. Objectives were to (i) characterize and classify the range of beluga-specific dive types over an annual cycle, (ii) propose dive functions based on optimal foraging theory, physiology, and association with environmental variables, and (iii) identify whether belugas undergo seasonal shifts in the frequency of dives associated with variable foraging strategies. Satellite-linked time-depth-recorders (TDRs) were attached to 13 male belugas from the EBS population in 2018 and 2019, and depth data were collected in time series at a 75 s sampling interval. Tags collected data for between 13 and 357 days, including three tags which collected data across all months. A total of 90,211 dives were identified and characterized by twelve time and depth metrics and classified into eight dive types using a Gaussian mixed modeling and hierarchical clustering analysis approach. Dive structures identify various seasonal behaviors and indicate year-round foraging. Shallower and more frequent diving during winter in the Bering Sea indicate foraging may be energetically cheaper, but less rewarding than deeper diving during summer in the Beaufort Sea and Arctic Archipelago, which frequently exceeded the aerobic dive limit previously calculated for this population. Structure, frequency and association with environmental variables supports the use of other dives in recovery, transiting, and navigating through sea ice. The current study provides the first comprehensive description of the year-round dive structures of any beluga population, providing baseline information to allow improved characterization and to monitor how this population may respond to environmental change and increasing anthropogenic stressors.

Variation in the diet of beluga whales in response to changes in prey availability: insights on changes in the Beaufort Sea ecosystem

2020 ◽  
Vol 647 ◽  
pp. 195-210 ◽  
Author(s):  
ES Choy ◽  
C Giraldo ◽  
B Rosenberg ◽  
JD Roth ◽  
AD Ehrman ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Prey Availability ◽  
Beaufort Sea ◽  
Delphinapterus Leucas ◽  
Fatty Acid Signature ◽  
Arctic Cod ◽  
Beluga Whales ◽  
Highly Sensitive ◽  
Condition Indices

The eastern Beaufort Sea (EBS) beluga whale Delphinapterus leucas population has experienced a 20 yr decline in inferred growth rates of individuals, which is hypothesized to have resulted from changes in prey availability. We used fatty acid signatures and stable isotope ratios to reconstruct the proportional contributions of 14 prey species to the diets of 178 beluga whales from 2011 to 2014. Prey estimates using quantitative fatty acid signature analysis suggest that EBS beluga whales primarily consume Arctic cod Boreogadus saida, a species highly sensitive to climate change. Prey estimates varied with year and sex and size class of the whales, with large males consuming the highest proportions of Arctic cod, and females consuming the highest proportions of capelin Mallotus villosus. Estimated proportional contributions of Arctic cod to beluga diet decreased from 2011 to 2014, coinciding with an increase in capelin. Belugas consumed the highest proportions of capelin and the lowest proportions of cod in 2014, the same year in which body condition indices were lowest in the whales. We hypothesize that changing conditions in the Beaufort Sea ecosystem may result in a decreased consumption of Arctic cod by belugas and increased consumption of capelin, which may result in a decline in condition. This may predominately affect females and juveniles since they consume the highest proportions of capelin; however, long-term monitoring is needed for confirmation. Understanding inter-annual variation in prey, and the longer-term nutritional implications of shifting from an Arctic cod- to a capelin-dominated diet should be a priority for monitoring EBS predators.

Bowhead and Beluga Whale Distributions, Sighting Rates, and Habitat Associations in the Western Beaufort Sea in Summer and Fall 2009–16, with Comparison to 1982–91

ARCTIC ◽  
2018 ◽  
Vol 71 (2) ◽  
Author(s):  
Janet T. Clarke ◽  
Megan C. Ferguson ◽  
Amy L. Willoughby ◽  
Amelia A. Brower
Keyword(s):  
Habitat Use ◽  
Sea Ice ◽  
Continental Slope ◽  
Beaufort Sea ◽  
Habitat Associations ◽  
Bowhead Whale ◽  
Line Transect ◽  
Outer Continental Shelf ◽  
Beluga Whales ◽  
Shallow Habitat

We analyzed data from line-transect aerial surveys for marine mammals conducted in the western Beaufort Sea (shore to 72˚ N, 140˚–157˚ W) from July to October of 2009–16 to investigate the distribution, behaviors, sighting rates, and habitat use preferences of bowhead and beluga whales. The habitat use data allowed for direct comparison with data collected in the same area from 1982 to 1991. Both species are ice-adapted, migrating through leads in sea ice in spring, and are seasonal inhabitants of the western Beaufort Sea during summer and fall. From 2009 to 2016, bowheads were seen in all survey months, with the highest overall sighting rate (whales per km) in August. Bowhead sighting rates were highest in the whales’ preferred habitats: outer shelf habitat (51–200 m depth) in July and inner shelf-shallow habitat (≤ 20 m depth) in August, September, and October. Beluga whales were also seen in all survey months, with highest overall sighting rate in July. Beluga whales were overwhelmingly associated with continental slope habitat (201–2000 m depth) in all months. Bowhead distribution and depth preferences in summer months of 2009–16 differed from those observed in 1982–91, when bowheads were not seen during limited survey effort in July and preferred outer continental shelf habitat in August. These differences indicate that bowhead whale preference for shallow shelf habitat now occurs earlier in summer than it used to. Beluga distribution and depth preference remained similar between 1982–91 and 2009–16, with strong preference for continental slope during both periods. Differences in sea ice cover habitat association for both species are likely due more to the relative lack of sea ice in recent years compared to the earlier period than to shifts in habitat preference. Habitat partitioning between bowhead and beluga whales in the western Beaufort Sea remained evident except in July, when both species used continental slope habitat. In July – October 2009–16, the distribution, sighting rates, and behavior of both bowheads and belugas in the western Beaufort showed considerable interannual variation, which underscores the importance of annual sampling to accurate records of the complex western Beaufort Sea ecosystem.

Linking mercury exposure to habitat and feeding behaviour in Beaufort Sea beluga whales

2008 ◽  
Vol 74 (3-4) ◽  
pp. 1012-1024 ◽  
Author(s):  
L.L. Loseto ◽  
G.A. Stern ◽  
D. Deibel ◽  
T.L. Connelly ◽  
A. Prokopowicz ◽  
...  
Keyword(s):  
Feeding Behaviour ◽  
Beaufort Sea ◽  
Mercury Exposure ◽  
Beluga Whales

scholarly journals Microplastics in beluga whales (Delphinapterus leucas) from the Eastern Beaufort Sea

2020 ◽  
Vol 150 ◽  
pp. 110723 ◽  
Author(s):  
R.C. Moore ◽  
L. Loseto ◽  
M. Noel ◽  
A. Etemadifar ◽  
J.D. Brewster ◽  
...  
Keyword(s):  
Beaufort Sea ◽  
Delphinapterus Leucas ◽  
Beluga Whales

scholarly journals Beluga whales in the western Beaufort Sea: Current state of knowledge on timing, distribution, habitat use and environmental drivers

2018 ◽  
Vol 152 ◽  
pp. 182-194 ◽  
Author(s):  
Kathleen M. Stafford ◽  
Megan C. Ferguson ◽  
Donna D.W. Hauser ◽  
Stephen R. Okkonen ◽  
Catherine L. Berchok ◽  
...  
Keyword(s):  
Habitat Use ◽  
Beaufort Sea ◽  
Environmental Drivers ◽  
Beluga Whales ◽  
Current State ◽  
Sea Current

scholarly journals Predation of archival tagged Dolly Varden, Salvelinus malma, reveals predator avoidance behaviour and tracks feeding events by presumed beluga whale, Delphinapterus leucas, in the Beaufort Sea

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Colin P. Gallagher ◽  
Luke Storrie ◽  
Michael B. Courtney ◽  
Kimberly L. Howland ◽  
Ellen V. Lea ◽  
...  
Keyword(s):  
Predator Avoidance ◽  
Beaufort Sea ◽  
Avoidance Behaviour ◽  
Delphinapterus Leucas ◽  
Feeding Frequency ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Beluga Whales ◽  
Predation Event ◽  
Stomach Temperature

Abstract Background We report compelling evidence suggesting a predation event of a pop-up satellite archival tagged anadromous Dolly Varden (Salvelinus malma) by a marine mammal during summer in the Beaufort Sea based on abrupt changes in temperature and vertical movements. This observation provides insight on predator avoidance behaviour by Dolly Varden and the predator’s feeding frequency while the tag was ingested. Based on published distribution and ecology information, we presumed the predator was a beluga whale (Delphinapterus leucas). Supplemental satellite telemetry data from previously tagged Dolly Varden and beluga whales were used to determine the extent of spatial and vertical overlap between species in the area where predation occurred. Results Prior to the predation event, depths and temperatures occupied by the tagged Dolly Varden averaged 1.1 m and 3.1 °C, respectively. On July 7, 2020, depths remained shallow apart from a sudden dive to 12.5 m (16:45 UTC) followed by a precipitous increase in temperature from 4.4 to 27.1 °C (16:52 UTC) suggesting predation by an endotherm. Subsequent readings indicated the endotherm had a resting stomach temperature of 36.1 °C. Including the predation event, eight separate feeding events were inferred during the 20-h period the tag was ingested (before presumed regurgitation) based on subsequent declines in stomach temperatures (mean decline to 31.1 °C) that took an average of 24.1 min to return to resting temperature. The predator occupied mainly shallow depths (mean = 2.3 m), overlapping with tagged belugas that spent 76.9% of their time occupying waters ≤ 2.5 m when frequenting the area occupied by tagged Dolly Varden in the Canadian Beaufort Sea in July. Back-calculation based on tag drift and mean displacement by tagged belugas indicated the predation likely occurred west of the Mackenzie Delta. Conclusion Our findings provide new information on both anti-predator behaviour by, and marine predators of, Dolly Varden in the Beaufort Sea. We provide the first estimate of feeding frequency and stomach temperature recovery in a presumed wild beluga, and evidence for shallow foraging behaviour by belugas. Elucidating the likely predator and exploring the extent of overlap between Dolly Varden and beluga whales contributes towards knowledge on the trophic interactions in the Beaufort Sea.

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