scholarly journals Increasing abundance of bowhead whales in West Greenland

2007 ◽  
Vol 3 (5) ◽  
pp. 577-580 ◽  
Author(s):  
Mads Peter Heide-Jørgensen ◽  
Kristin Laidre ◽  
David Borchers ◽  
Filipa Samarra ◽  
Harry Stern
Keyword(s):  
Survey Design ◽  
Large Population ◽  
Aerial Survey ◽  
Bowhead Whale ◽  
West Greenland ◽  
Threshold Size ◽  
Bowhead Whales ◽  
Abundance Estimate ◽  
Surface Time ◽  
Severe Reduction

In April 2006, a dedicated survey of bowhead whales ( Balaena mysticetus ) was conducted on the former whaling ground in West Greenland to determine the current wintering population abundance. This effort included a double platform aerial survey design, satellite tracking of the movements of nine whales, and estimation of high-resolution surface time from 14 whales instrumented with time–depth recorders. Bowhead whales were estimated to spend an average of 24% (cv=0.03) of the time at or above 2 m depth, the maximum depth at which they can be seen on the trackline. This resulted in a fully corrected abundance estimate of 1229 (95% CI: 495–2939) bowhead whales when the availability factor was applied and sightings missed by observers were corrected. This surprisingly large population estimate is puzzling given that the change in abundance cannot be explained by a recent or rapid growth in population size. One possible explanation is that the population, which demonstrates high age and sex segregation, has recently attained a certain threshold size elsewhere, and a higher abundance of mature females appears on the winter and spring feeding ground in West Greenland. This in combination with the latest severe reduction in sea ice facilitating access to coastal areas might explain the surprising increase in bowhead whale abundance in West Greenland.

scholarly journals Distribution and Abundance of the Eastern Canada – West Greenland Bowhead Whale Population Based on the 2013 High Arctic Cetacean Survey

2020 ◽  
Vol 11 ◽  
Author(s):  
Thomas Doniol-Valcroze ◽  
Jean-François Gosselin ◽  
Daniel G. Pike ◽  
Jack W. Lawson ◽  
Natalie C. Asselin ◽  
...  
Keyword(s):  
High Arctic ◽  
Diving Behaviour ◽  
Bowhead Whale ◽  
Survey Area ◽  
Eastern Canada ◽  
West Greenland ◽  
Bowhead Whales ◽  
Abundance Estimate ◽  
Track Line ◽  
Canada West

The hunting of bowhead whales (Balaena mysticetus) is an integral part of Inuit culture. An up-to-date abundance estimate of the entire Eastern Canada – West Greenland (EC-WG) bowhead population is necessary to support sustainable management of this harvest. The High Arctic Cetacean Survey (HACS) was conducted in August 2013, primarily to update abundance estimates for known stocks of Baffin Bay narwhal (Monodon monoceros). As the ranges of narwhal and bowhead largely overlap, the survey area was expanded to cover the summer range of bowhead whales. Bowhead whale abundance was estimated using 3 aircraft to cover the large survey area within a short time frame. Distance sampling methods were used to estimate detection probability away from the track line. Double platform with mark-recapture methods were used to correct for the proportion of whales missed by visual observers on the track line (perception bias). Abundance in Isabella Bay, an area known for high bowhead density, was estimated using density surface modelling to account for its complex shape and uneven coverage. Estimates were corrected for availability bias (whales that were not available for detection because they were submerged when the aircraft passed overhead) using a recent analysis of satellite-linked time depth recorders transmitting information on the diving behaviour of bowhead whales in the study area in August of the same survey year. The fully corrected abundance estimate for the EC-WG bowhead whale population was 6,446 (95% CI: 3,838–10,827). Possible sources of uncertainty include incomplete coverage and the diving behaviour of bowhead whales. These results confirm earlier indications that the EC-WG stock is continuing to recover from past overexploitation.

scholarly journals Size and trends of the bowhead whale, beluga and narwhal stocks wintering off West Greenland

2002 ◽  
Vol 4 ◽  
pp. 191 ◽  
Author(s):  
MP Heide-Jørgensen ◽  
Mario Acquarone
Keyword(s):  
Bowhead Whale ◽  
Delphinapterus Leucas ◽  
Line Transect ◽  
Total Abundance ◽  
West Greenland ◽  
Bowhead Whales ◽  
Line Transect Survey ◽  
Monodon Monoceros ◽  
Northern Edge ◽  
Index Estimate

To assess the size and trends of the abundance of the bowhead whale (Balaena mysticetus), the beluga, or white whale (Delphinapterus leucas), and the narwhal (Monodon monoceros) visual aerial surveys were conducted in West Greenland in March 1998 and 1999. An estimated 49 bowhead whales (95% CI: 13 to 188) were present at the surface in 1998. Data from land-based observations enabled correction for bowhead whales that were not available at the surface to be seen during the survey. By applying a rounded average of 80% (SE=3) for submergence an estimate of 246 bowhead whales (95% CI: 62 to 978) in 1998 was obtained. The 76 and 47 sightings of beluga pods in 1998 and 1999, respectively, had distributions similar to those of previous surveys with the highest concentration at the northern edge of the northern part of Store Hellefiskebanke. No belugas were seen in the southernmost area between Maniitsoq and Paamiut. The index estimate of the abundance of belugas comparable with previous surveys was 929 (95% CI: 563 to 1,533) in 1998 and 735 (95% CI: 436 to 1,239) in 1999. When analysing the sightings as a line-transect survey and correcting for whales that were either submerged or at the surface but missed by the observers an estimated 7,941 (95% CI: 3,650 to 17,278) belugas wintered in West Greenland in 1998-1999. The uncorrected estimate of narwhal abundance was 524 (95% CI: 214 to 1,284) and correcting for the same biases as for the belugas gives a total abundance of 2,861 (95% CI: 954 to 8,578) narwhals in 1998-1999.

Seasonal diving and foraging behaviour of Eastern Canada-West Greenland bowhead whales

2020 ◽  
Vol 643 ◽  
pp. 197-217 ◽  
Author(s):  
SME Fortune ◽  
SH Ferguson ◽  
AW Trites ◽  
B LeBlanc ◽  
V LeMay ◽  
...  
Keyword(s):  
Climate Change ◽  
Late Summer ◽  
Calanoid Copepods ◽  
Eastern Canada ◽  
West Greenland ◽  
Bowhead Whales ◽  
Seasonal Movement ◽  
Dive Behaviour ◽  
Calanus Glacialis ◽  
Canada West

Climate change may affect the foraging success of bowhead whales Balaena mysticetus by altering the diversity and abundance of zooplankton species available as food. However, assessing climate-induced impacts first requires documenting feeding conditions under current environmental conditions. We collected seasonal movement and dive-behaviour data from 25 Eastern Canada-West Greenland bowheads instrumented with time-depth telemetry tags and used state-space models to examine whale movements and dive behaviours. Zooplankton samples were also collected in Cumberland Sound (CS) to determine species composition and biomass. We found that CS was used seasonally by 14 of the 25 tagged whales. Area-restricted movement was the dominant behaviour in CS, suggesting that the tagged whales allocated considerable time to feeding. Prey sampling data suggested that bowheads were exploiting energy-rich Arctic copepods such as Calanus glacialis and C. hyperboreus during summer. Dive behaviour changed seasonally in CS. Most notably, probable feeding dives were substantially shallower during spring and summer compared to fall and winter. These seasonal changes in dive depths likely reflect changes in the vertical distribution of calanoid copepods, which are known to suspend development and overwinter at depth during fall and winter when availability of their phytoplankton prey is presumed to be lower. Overall, CS appears to be an important year-round foraging habitat for bowheads, but is particularly important during the late summer and fall. Whether CS will remain a reliable feeding area for bowhead whales under climate change is not yet known.

Occurrence of killer whale Orcinus orca rake marks on Eastern Canada-West Greenland bowhead whales Balaena mysticetus

Polar Biology ◽  
2013 ◽  
Vol 36 (8) ◽  
pp. 1133-1146 ◽  
Author(s):  
N. R. Reinhart ◽  
S. H. Ferguson ◽  
W. R. Koski ◽  
J. W. Higdon ◽  
B. LeBlanc ◽  
...  
Keyword(s):  
Killer Whale ◽  
Orcinus Orca ◽  
Balaena Mysticetus ◽  
Eastern Canada ◽  
West Greenland ◽  
Bowhead Whales ◽  
Canada West

scholarly journals First abundance estimate of the Antillean manatee (Trichechus manatus manatus) in Brazil by aerial survey – CORRIGENDUM

2015 ◽  
Vol 96 (4) ◽  
pp. 967-967 ◽  
Author(s):  
Maria Danise Alves ◽  
Paul Gerhard Kinas ◽  
Miriam Marmontel ◽  
João Carlos Gomes Borges ◽  
Alexandra Fernandes Costa ◽  
...  
Keyword(s):  
Aerial Survey ◽  
Trichechus Manatus ◽  
Abundance Estimate

scholarly journals Mitogenomics and the genetic differentiation of contemporary Balaena mysticetus (Cetacea) from Svalbard

2020 ◽  
Author(s):  
Lutz Bachmann ◽  
Andrea A Cabrera ◽  
Mads Peter Heide-Jørgensen ◽  
Olga V Shpak ◽  
Christian Lydersen ◽  
...  
Keyword(s):  
Genetic Differentiation ◽  
High Throughput Sequencing ◽  
Demographic History ◽  
Bowhead Whale ◽  
Recent Common Ancestor ◽  
Mitochondrial Genomes ◽  
Balaena Mysticetus ◽  
Bowhead Whales ◽  
Most Recent Common Ancestor ◽  
Loop Region

Abstract Full mitochondrial genomes were assembled for 12 recently sampled animals from the Svalbard bowhead whale (Balaena mysticetus) stock via high-throughput sequencing data, facilitating analysis of the demographic history of the population for the first time. The Svalbard population has retained noticeable amounts of mitochondrial genome diversity despite extreme historical harvest levels. Haplotype and nucleotide diversities were similar to those estimated earlier for other bowhead whale populations. The reconstructed demographic history was in accordance with a boom–bust scenario, combining a slight Pleistocene population growth 25 000–35 000 years ago and a Holocene decline. Employing a mutation rate of 3.418 × 10–8 substitutions per site per year, the time to the most recent common ancestor for the mitochondrial genomes of the contemporary Svalbard bowhead whales was estimated to be 68 782 (54 353–83 216) years before the present. Based on 370 bp fragments of the D-loop region, significant genetic differentiation was detected between all extant bowhead whale populations across the circumpolar Arctic. Thus, the Svalbard bowhead whales can be regarded as a population with its own genetic legacy.

scholarly journals Comment on “Genetic analysis of 16th-century whale bones prompts a revision of the impact of Basque whaling on right and bowhead whales in the western North Atlantic”

2006 ◽  
Vol 84 (7) ◽  
pp. 1059-1065 ◽  
Author(s):  
Aldemaro Romero ◽  
Shelly Kannada
Keyword(s):  
Genetic Analysis ◽  
North Atlantic ◽  
Small Sample ◽  
Bowhead Whale ◽  
16Th Century ◽  
Bowhead Whales ◽  
The North ◽  
The North Atlantic ◽  
Red Bay ◽  
The Impact

Rastogi et al. presented their genetic analysis of 16th-century whale bones found on a Basque whaling ship excavated from Red Bay, Labrador Peninsula, Canada. Based on the results from a very small sample, these authors concluded that whaling populations were already depleted before the onset of whaling. This is in direct contradiction to historical data. They also implied that the Basques were the only Europeans whaling in the North Atlantic before the onset of Yankee whaling and that there was a belief that Basque whalers historically killed equal numbers of right and bowhead whales. Here we present data based on historical and archaeological records generated by several authors using different methodologies, which clearly show that (i) Basques were not the only whalers that impacted cetacean populations in the North Atlantic; (ii) the number of whales killed by different peoples for approximately two centuries indicates that both right and bowhead whale population levels were much higher than typically assumed; and (iii) for many years there have been records published indicating that the Basques and others killed more bowhead whales than right whales, at least in the western North Atlantic.

Recent status of bowhead whales, Balaena mysticetus, in the wintering grounds off West Greenland

1996 ◽  
Vol 15 (2) ◽  
pp. 115-125 ◽  
Author(s):  
RANDALL R. REEVES ◽  
MADS PETER HEIDE-JØRGENSEN
Keyword(s):  
Balaena Mysticetus ◽  
Wintering Grounds ◽  
West Greenland ◽  
Bowhead Whales

Accuracy of Pup Classifications and Its Effect on Population Estimates in the Hooded Seal (Cystophora cristata)

1988 ◽  
Vol 45 (4) ◽  
pp. 715-719 ◽  
Author(s):  
G. B. Stenson ◽  
R. A. Myers
Keyword(s):  
Developmental Stages ◽  
Survey Design ◽  
Aerial Survey ◽  
Similar Proportion ◽  
Population Estimates ◽  
Hooded Seal ◽  
Cystophora Cristata ◽  
Current Survey ◽  
Survey Estimates ◽  
Misclassification Rates

Information from the classification of age-specific developmental stages has been used to adjust aerial survey estimates of pup production in a number of species of seals, including the hooded seal (Cystophora cristata). We test the assumption that hooded seal pups were accurately and consistently classified according to developmental stage and examine the consequences of misclassifications upon adjusted population estimates. We determined overall misclassification rates, the effect of survey height on classifications, and interobserver variability. At ice level, misclassifications rates were low (<3%). From an altitude of 30 m, newborn pups could not be classified correctly and misclassification rates for the two other stages of attended pups varied between 6.4 and 21.3%. There was no evidence of an overall bias in classifications or differences among observers although there was a significant interaction between day and stage. Individual pups appear to have been misclassified independently by each observer. Under actual survey conditions, observers classified a similar proportion of pups into each recognizable stage. The misclassification rates we observed did not significantly alter the previous population estimate. Methods for improving the current survey design include modifying classification criteria, providing observers with a period of on-ice training, and reducing the width of survey transects.

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