scholarly journals Movements and Inferred Foraging by Bowhead Whales in the Canadian Beaufort Sea during August and September, 2006–12

ARCTIC ◽  
2017 ◽  
Vol 70 (2) ◽  
pp. 161 ◽  
Author(s):  
Lois A. Harwood ◽  
Lori T. Quakenbush ◽  
Robert J. Small ◽  
J. Craig George ◽  
James Pokiak ◽  
...  

Each spring, most bowhead whales of the Bering-Chukchi-Beaufort (BCB) population migrate to the southeast Beaufort Sea and summer in Canadian waters. In August and September, they form aggregations, which are known to occur mainly in the shallow, shelf waters when oceanographic conditions promote concentration of their zooplankton prey. The movements of individual bowheads while they occupy these late summer habitats are less well known; our knowledge is based on photographic evidence and limited tagging studies conducted from 1982 to 2000. In this study, 85% (17) of the 20 satellite-tagged whales that could have spent some time in the Canadian portion of the Beaufort Sea during late summer 2006 to 2012 spent all or part of August and September there. We analyzed location data for 16 whales, using a two-state switching correlated random walk (CRW) behavioural model, and classified locations in the Canadian waters as associated with lingering behaviour (inferred foraging) or directed travel. We found that these whales spent the greatest proportion of their time lingering (59%), followed by traveling (22%), and transitioning between lingering and traveling (19%). Using only lingering locations for these tagged whales in all study years pooled, we calculated kernel densities and defined five areas within the 75% density contour as aggregation areas. Together, the five aggregation areas we defined comprised 25 341 km2, 14.1% of the total area used by these tagged whales in Canadian waters during August and September of the deployment years. Three aggregation areas were located in shallow waters of the Beaufort Sea Shelf and were used almost exclusively by immature tagged whales in our sample. Two other aggregation areas were observed, one in Darnley Bay and one in Viscount Melville Sound in the Canadian Arctic Archipelago. Each of these was used by one mature whale. Tagged whales were observed to use one or two aggregation areas in a single season, and rarely more. The proportion of lingering time spent in each aggregation area was highly variable among individuals. The largest aggregation area (10 877 km2), located over the Beaufort Shelf north of the Tuktoyaktuk Peninsula (5 – 52 m depth), was used by 13 of the 16 tagged whales, almost exclusively by the immature whales, including three of four that were tracked in two consecutive summers. The Beaufort Shelf overall (and possibly the Tuktoyaktuk Shelf, including the Outer Shelf, in particular) was especially important for immature bowhead whales, while mature whales used habitats beyond the Beaufort Shelf during late summer. Findings may be important to inform both decisions on management and mitigative actions relating to bowhead whale use of the Beaufort Shelf and studies that aim to improve our understanding of the prey base of BCB bowhead whales in the Canadian Beaufort Sea region.

2000 ◽  
Vol 78 (7) ◽  
pp. 1168-1181 ◽  
Author(s):  
Bruce R Mate ◽  
Gregory K Krutzikowsky ◽  
Martha H Winsor

From 30 August to 6 September 1992, we tagged 12 juvenile bowhead whales (Balaena mysticetus) with Argos satellite-monitored radio tags in the Canadian Beaufort Sea off the Mackenzie River Delta. Eight tags documented [Formula: see text]9820 km of movements between 392 locations during 111 whale-tracking days. The whales did not move in unison. Individual movements and average speeds (1.1-5.8 km/h) varied widely. One whale stayed in Mackenzie Bay for 23.5 d, while the rest stayed an average of only 2.4 d. The majority of locations for all whales were in shallow water: 65% at <50 m depth and 87% at <100 m depth. Seven whales went into water >100 m deep and four were in water >500 m deep. The whale with the longest record traveled [Formula: see text]3886 km to Siberia in 32.5 d, averaging 5.0 km/h. Its westerly route through the Beaufort and Chukchi seas was between 70° and 72°N and primarily in heavy ice ([Formula: see text]90% coverage), which was continuous west of 151°W. This whale's speed was faster, though not significantly, in heavy ice than in more open water. This is the first detailed documentation of the route and speed of a bowhead whale during its fall migration from Canadian to Russian waters.


1982 ◽  
Vol 39 (3) ◽  
pp. 395-406 ◽  
Author(s):  
P. C. Craig ◽  
W. B. Griffiths ◽  
L. Haldorson ◽  
H. McElderry

Fish use of Beaufort Sea coastal waters was examined during summer and winter periods 1977–80. Arctic cod (Boreogadus saida) were abundant but their occurrence was highly variable. They accounted for 8–78% of all fish caught in Simpson Lagoon during two summers, and 0.4–100% of catches at various coastal sites in winter. Arctic cod increased in abundance in the lagoon during late summer and some association was noted between their numbers and higher salinities but not temperature or turbidity. Some cod remained in shallow waters in early winter but deeper areas were used through the winter, and the highest catch rate was recorded 175 km offshore. Principal foods of the cod in nearshore waters were mysids (Mysis litoralis, M. relicta), amphipods (Onisimus glacialis), and copepods. The cod caught were generally small (60–170 mm) and young (ages 1–3). Most males matured at ages 2–3 and females at age 3. These size, age, and maturity characteristics indicate a life history strategy (r-selection) unlike that typified by many other arctic fish populations, particularly the freshwater and anadromous species which tend to be slow growing, late maturing and long-lived (K-selection).Key words: Arctic cod, Boreogadus saida; Beaufort Sea, distribution, life history strategy


2001 ◽  
Vol 55 (3) ◽  
pp. 371-379 ◽  
Author(s):  
Arthur S. Dyke ◽  
James M. Savelle

AbstractThe fossil remains of 43 bowhead whales were mapped on the raised beaches of western Wollaston Peninsula, Victoria Island, Canadian Arctic, near the historic summer range limit of the Bering Sea stock in the Beaufort Sea. The elevations and radiocarbon ages of the remains demonstrate that the bowhead ranged commonly into the region following the submergence of Bering Strait at ca. 10,000 14C yr B.P. until ca. 8500 14C yr B.P. During the same interval, bowheads ranged widely from the Beaufort Sea to Baffin Bay. Subsequently, no whales reached Wollaston Peninsula until ca. 1500 14C yr B.P. Late Holocene populations evidently were small, or occupations were brief, in comparison to those of the early Holocene. Although the late Holocene recurrence may relate to the expansion of pioneering Thule whalers eastward from Alaska, there are few Thule sites and limited evidence of Thule whaling in the area surveyed to support this suggestion.


2013 ◽  
Vol 134 (6) ◽  
pp. 4323-4334 ◽  
Author(s):  
Russell A. Charif ◽  
Ashakur Rahaman ◽  
Charles A. Muirhead ◽  
Michael S. Pitzrick ◽  
Ann M. Warde ◽  
...  

2018 ◽  
Vol 131 (3) ◽  
pp. 270-279
Author(s):  
Lois A. Harwood ◽  
Ellen V. Lea ◽  
Stephen A. Raverty ◽  
Patricia A. Hall ◽  
Erin Linn ◽  
...  

Each spring, most Bowhead Whales (Balaena mysticetus) of the Bering-Chukchi-Beaufort (BCB) population migrate to the Canadian Beaufort Sea and Amundsen Gulf for summer feeding. Occasionally, Inuvialuit hunters and others observe beachcast (stranded) or adrift Bowhead Whale carcasses. From 1987 to 2016, 26 such occurrences were recorded. Most (65%) were found by Inuvialuit hunters travelling on the land, with the majority (54%) reported during 2000–2006. Bowhead Whale carcasses were found widely distributed throughout the region, with twice as many in Amundsen Gulf (65%) compared with the southeastern Beaufort Sea (35%). It was possible to measure or estimate standard length for 17 of 26 specimens, and all were either provisional ‘subadults’ (7–9.5 m; n = 10; 59%) or provisional ‘mature adults’ (13–16 m; n = 7; 41%). The cause(s) of mortality was not determined for any of the specimens. Whales in the ‘subadult’ group were likely 1–4 years old, while the ‘mature adult’ group were likely mostly mature animals (~25 y), including some potentially very old (>100 y). There was evidence or direct observation of Polar Bears (Ursus maritimus) and/or Grizzly Bears (U. arctos) scavenging at 60% of the carcasses for which presence or absence of bears or bear sign (scats and/or tracks) was reported. It is important to continue to record incidental observations of beachcast Bowhead Whales, as this may enable stranding rates to be evaluated.


ARCTIC ◽  
2020 ◽  
Vol 73 (3) ◽  
pp. 278-291
Author(s):  
Justin Olnes ◽  
John J. Citta ◽  
Lori T. Quakenbush ◽  
John C. George ◽  
Lois A. Harwood ◽  
...  

We used satellite telemetry to examine bowhead whale movement behavior, residence times, and dive behavior in the Alaskan Beaufort Sea, 2006 – 18. We explored the timing and duration of use of three subregions (western, central, eastern) within the Alaskan Beaufort Sea and applied a two-state switching state-space model to infer bowhead whale behavior state as either transiting or lingering. Transiting whales made direct movements whereas lingering whales changed direction frequently and were presumably feeding. In spring, whales migrated across the Alaskan Beaufort Sea in 7.17 ± 0.41 days, primarily off the continental shelf over deep water. During the autumn migration, whales spent over twice as much time crossing the Alaskan Beaufort Sea than in spring, averaging 18.66 ± 2.30 days, spending 10.05 ± 1.22 days in the western subregion near Point Barrow. Most whales remained on the shelf during the autumn migration and frequently dove to the seafloor, where they spent 45% of their time regardless of behavioral state. Consistent dive behavior in autumn suggests that the whales were looking for food while migrating, and the identification of lingering locations likely reflects feeding. The lack of lingering locations in the eastern and central subregions suggests that prey densities are rarely sufficient to warrant whales pausing their migration for multiple days, unlike in the western subregion near Point Barrow, where bowhead whales regularly lingered for long periods of time.


2014 ◽  
Vol 135 (3) ◽  
pp. 1641-1641
Author(s):  
Russell A. Charif ◽  
Ashakur Rahaman ◽  
Charles A. Muirhead ◽  
Michael S. Pitzrick ◽  
Ann M. Warde ◽  
...  

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