scholarly journals Surveys of belugas and narwhals in the Canadian High Arctic in 1996

2002 ◽  
Vol 4 ◽  
pp. 169 ◽  
Author(s):  
Stuart Innes ◽  
MP Heide-Jørgensen ◽  
Jeff L Laake ◽  
Kristin L Laidre ◽  
Holly J Cleator ◽  
...  
Keyword(s):  
High Arctic ◽  
Aerial Survey ◽  
Delphinapterus Leucas ◽  
Line Transect ◽  
Canadian High Arctic ◽  
Distance Measurements ◽  
Distance Information ◽  
Surface Time ◽  
Summer Range ◽  
Using Data

The summer range of belugas (Delphinapterus leucas) and narwhals (Monodon monoceros) in Prince Regent Inlet, Barrow Strait and Peel Sound in the Canadian High Arctic was surveyed from 31 July to 3 August 1996 with a visual aerial survey of offshore areas and photographic aerial surveys of concentration areas. The visual survey estimate based on the number of belugas visible to the observers using systematic line transect methods was 10,347 (cv = 0.28). This included corrections for whales that were missed by the observers, observations without distance measurements and an estimate of 1,949 (cv=0.22) belugas from a photographic survey in southern Peel Sound. Using data from belugas tagged with satellite-linked time-depth recorders, the estimate was adjusted for individuals that were diving during the survey which resulted in an estimate of 18,930 belugas (cv = 0.28). Finally, counts of belugas in estuaries, corrected for estuarine surface time, were added to provide a complete estimate of 21,213 belugas (95% CI 10,985 to 32,619). The estimated number of narwhals corrected for sightings that were missed by observers was 16,364 (cv = 0.24). Adjusting this for sightings without distance information and correcting for whales that were submerged produced an estimate of 45,358 narwhals (95% CI 23,397 to 87,932).

scholarly journals Visibility of St Lawrence belugas to aerial photography, estimated by direct observation

2002 ◽  
Vol 4 ◽  
pp. 259 ◽  
Author(s):  
Michael CS Kingsley ◽  
Isabelle Gauthier
Keyword(s):  
Water Clarity ◽  
Population Based ◽  
Aerial Survey ◽  
Aerial Photographs ◽  
Delphinapterus Leucas ◽  
Secchi Disk ◽  
Lawrence Estuary ◽  
Summer Range ◽  
Different Depths ◽  
St Lawrence Estuary

The depleted population of belugas (Delphinapterus leucas) inhabiting the St Lawrence estuary, Canada, was monitored by periodic photographic aerial surveys. In order to correct counts made on aerial survey film and to obtain an estimate of the true size of the population, the diving behaviour and the visibility from the air of these animals was studied. A Secchi-disk turbidity survey in the belugas’ summer range showed that water clarity varied between 1.5 m and 11.6 m. By studying aerial photographs of sheet-plastic models of belugas that had been sunk to different depths below the surface, we found that models of white adults could be seen down to about the same depth as a Secchi disk, but no deeper. Smaller models of dark-grey juveniles could only be seen down to about 50% of Secchi-disk depth. By observing groups of belugas from a hovering helicopter and recording their disappearances and re-appearances, it was found that they were visible for 44.3% of the time, and that an appropriate correction for single photographs would be to multiply the photographic count by about 222% (SE 20%). For surveys in which there was overlap between adjacent frames, the estimated correction would be 209% (SE 16%). This correction factor was slightly conservative and gave an estimate of the true size of the population, based on a single survey, of 1,202 belugas (SE 189) in 1997. An estimate for 1997 based on smoothing 5 surveys 1988–1997 was 1,238 (SE 119).

scholarly journals Conservation of Peary caribou based on a recalculation of the 1961 aerial survey on the Queen Elizabeth Islands, Arctic Canada

Rangifer ◽  
2005 ◽  
Vol 25 (4) ◽  
pp. 65 ◽  
Author(s):  
Frank L. Miller ◽  
Samuel J. Barry ◽  
Wendy A. Calvert
Keyword(s):  
Confidence Interval ◽  
Rangifer Tarandus ◽  
High Arctic ◽  
Aerial Survey ◽  
Relative Importance ◽  
Canadian High Arctic ◽  
Accurate Evaluation ◽  
The Past ◽  
Future Potential ◽  
Ecological Basis

The estimate of 25 845 Peary caribou (Rangifer tarandus pearyi) on the Queen Elizabeth Islands (QEI) in the Canadian High Arctic in summer 1961 is the only nearly range-wide 'benchmark' for the past number of caribou. No variances or confidence intervals were calculated for this estimate and no estimates were calculated for Peary caribou on the three major islands of Ellesmere, Devon, and Axel Heiberg. We reexamined the 1961 raw data by grouping the QEI into five island-complexes ('eco-units') and calculating, for each unit, the estimated number of caribou and the standard error, and the 95% confidence interval of the estimate, using a 'bootstrap' technique with 100 000 replications. Our goal was to provide an ecological basis for evaluating subsequent changes in numbers rather than relying on single-island evaluations. Our bootstrap reanalysis produced an estimate of 28 288 ± 2205 SE with a 95% CI of 20 436—37 031 Peary caribou on the QEI in summer 1961. Substantial differences in density were apparent among the five eco-units, with about a 50-fold difference from 0.01 caribou • km-2 in the Eastern eco-unit to 0.5 caribou • km-2 in the Northwestern eco-unit. The 1961 findings, with our subsequent reexamination, are crucial to any evaluation of trends for the number of Peary caribou on the QEI and the relative importance of individual eco-units for these animals. These findings also allow a more accurate evaluation of the magnitude of the subsequent decline of Peary caribou on the QEI during the last four decades and may help predict future potential levels for caribou in each of the five eco-units.

Sexual differences in the foraging ecology of 19th century beluga whales ( Delphinapterus leucas ) from the Canadian High Arctic

2020 ◽  
Vol 36 (2) ◽  
pp. 451-471 ◽  
Author(s):  
Paul Szpak ◽  
Marie‐Hélène Julien ◽  
Thomas C. A. Royle ◽  
James M. Savelle ◽  
Dongya Y. Yang ◽  
...  
Keyword(s):  
19Th Century ◽  
Foraging Ecology ◽  
High Arctic ◽  
Sexual Differences ◽  
Delphinapterus Leucas ◽  
Canadian High Arctic ◽  
Beluga Whales

An estimate of the fraction of belugas (Delphinapterus leucas) in the Canadian high Arctic that winter in West Greenland

Polar Biology ◽  
2003 ◽  
Vol 26 (5) ◽  
pp. 318-326 ◽  
Author(s):  
M. P. Heide-Jørgensen ◽  
P. Richard ◽  
R. Dietz ◽  
K. L. Laidre ◽  
J. Orr ◽  
...  
Keyword(s):  
High Arctic ◽  
Delphinapterus Leucas ◽  
Canadian High Arctic ◽  
West Greenland

An on-ice aerial survey of the Kane Basin polar bear (Ursus maritimus) subpopulation

Polar Biology ◽  
2021 ◽  
Author(s):  
Øystein Wiig ◽  
Stephen N. Atkinson ◽  
Erik W. Born ◽  
Seth Stapleton ◽  
Todd Arnold ◽  
...  
Keyword(s):  
Distance Sampling ◽  
Open Water ◽  
High Arctic ◽  
Ursus Maritimus ◽  
Aerial Survey ◽  
Arctic Sea Ice ◽  
Line Transect ◽  
Polar Bears ◽  
The North ◽  
North Water

AbstractThere is an imminent need to collect information on distribution and abundance of polar bears (Ursus maritimus) to understand how they are affected by the ongoing decrease in Arctic sea ice. The Kane Basin (KB) subpopulation is a group of high-latitude polar bears that ranges between High Arctic Canada and NW Greenland around and north of the North Water polynya (NOW). We conducted a line transect distance sampling aerial survey of KB polar bears during 28 April–12 May 2014. A total of 4160 linear kilometers were flown in a helicopter over fast ice in the fjords and over offshore pack ice between 76° 50′ and 80° N′. Using a mark-recapture distance sampling protocol, the estimated abundance was 190 bears (95% lognormal CI: 87–411; CV 39%). This estimate is likely negatively biased to an unknown degree because the offshore sectors of the NOW with much open water were not surveyed because of logistical and safety reasons. Our study demonstrated that aerial surveys may be a feasible method for obtaining abundance estimates for small subpopulations of polar bears.

Distribution and Movements of Belugas, Delphinapterus leucas, in the Canadian High Arctic

1994 ◽  
Vol 51 (7) ◽  
pp. 1653-1663 ◽  
Author(s):  
Thomas G. Smith ◽  
A. R. Martin
Keyword(s):  
Coastal Waters ◽  
High Arctic ◽  
Delphinapterus Leucas ◽  
Canadian High Arctic ◽  
Directed Movement ◽  
Seasonal Movements ◽  
Devon Island ◽  
Aerial Surveys ◽  
Fast Ice ◽  
Somerset Island

Belugas, Delphinapterus leucas, move into the coastal waters of Somerset Island as soon as the annual land-fast ice breaks up in late June – early July. Six bays or inlets which receive the outflow of rivers are the major areas of summer aggregation. Belugas captured and equipped with satellite-linked UHF transmitters in Cunningham Inlet (Barrow Strait), Elwin Bay (Prince Regent Inlet), and Creswell Bay moved west into Peel Sound where they frequented two other estuaries. Rapid and directed movement out of Peel Sound occurred in late August. All of the animals which transmitted locations into September or October moved to eastern Devon Island and Jones Sound. The longest period of transmission was 75 d, lasting until mid-October. Belugas tagged in three different locations around Somerset Island in the summers of 1988–93 showed a well-defined and consistent pattern of behaviour. Aerial surveys done during this period confirm that the vast majority of belugas in this region are involved in these seasonal movements.

scholarly journals Distribution and abundance of Canadian High Arctic belugas, 1974-1979

2002 ◽  
Vol 4 ◽  
pp. 87 ◽  
Author(s):  
William R Koski ◽  
Kerwin J Finley
Keyword(s):  
Late Summer ◽  
High Arctic ◽  
Delphinapterus Leucas ◽  
Polar Cod ◽  
Canadian High Arctic ◽  
Devon Island ◽  
The North ◽  
Polar Cod Boreogadus Saida ◽  
North Water ◽  
Somerset Island

We conducted >236,000 km of aerial surveys and some supplementary studies of belugas (Delphinapterus leucas) in the central and eastern Canadian High Arctic in 974-79. Belugas that wintered in the “North Water” in Baffin Bay moved southwest into Lancaster Sound in April and early May. The main westward migration into Lancaster Sound occurred over a 2 to 3 week period during late June to late July. Estuaries along Somerset Island were occupied for <3 weeks from mid-July to mid-August. Little feeding occurred in estuaries. From mid-August until fall migration began in mid-September belugas occupied estuaries and offshore waters in Peel Sound. Fall migration eastward through Lancaster Sound was exclusively along the south coast of Devon Island, highly co-ordinated, and rapid; most of the population passed through the sound in <1 week. The whales then moved north along the east coast of Devon Island; some entered Jones Sound while others crossed directly to SE Ellesmere Island. Most calving occurred in July and early August; calving was not seen in estuaries and probably occurred offshore. Excluding calves, adults and yearlings formed 77% and 8.4%, respectively, of the population. The proportion of calves during mid-August was consistent with a triennial calving cycle. During late summer, belugas fed on coastal concentrations of polar cod (Boreogadus saida), under pan ice offshore (probably on cod), and in deep offshore waters. The size of the Canadian High Arctic population in the late 1970s was estimated to be at least 10,250 to 12,000 animals without allowing for animals that may have passed between surveys or that were below the surface at the time of the counts.

Coping with variation in aerial survey protocol for line-transect sampling

2008 ◽  
Vol 35 (4) ◽  
pp. 289 ◽  
Author(s):  
Jeff Laake ◽  
Richard J. Guenzel ◽  
John L. Bengtson ◽  
Peter Boveng ◽  
Michael Cameron ◽  
...  
Keyword(s):  
Aerial Survey ◽  
Line Transect ◽  
Antilocapra Americana ◽  
Line Transect Sampling ◽  
Transect Sampling ◽  
Sources Of Variation ◽  
Distance Data ◽  
Biased Estimators ◽  
Using Data ◽  
Survey Protocol

Altitude and flight speed affect detection probability and they typically vary during the course of most aerial surveys. We demonstrate how these sources of variation can be accommodated with covariates in a line-transect analysis using data from a pronghorn (Antilocapra americana) survey in Wyoming and a survey of Antarctic ice seals (Lobodon carcinophaga, Leptonychotes weddellii, Hydrurga leptonyx, Ommatophoca rossii). We also show how the likelihood for binned distance data can be modified to allow for variation in altitude. As an alternative, we develop an estimator for aerial line-transect sampling based on vertical angles rather than distance. With a small simulation study, we show that our estimators are unbiased and are preferable to using biased estimators based on fixed-distance intervals derived from average altitude.

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