Polar Bear Specialist Group of the IUCN Meetings
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--Nichole Hoskin 16:58, 7 August 2008 (EST)
Related Links: Polar Bears U.S. Geological Survey Reports on Polar Bear Population Status in the U.S. and Canada Listing of Polar Bears as Threatened under the US Endangered Species Act
Contents |
Proceedings of the 1st International Scientific Meeting on the Polar Bear, 1965:
Canadian Wildlife Service Report
"Intensive polar bear hunting by whalers and sealers since the early 17th century has probably resulted in a reduced population. Depletions were first noted on the west coast of Spitsbergen and Novaya Zemlya in the middle of the 19th century. Further significant depletions, attributed to overhunting, have occurred in Greenland and the Soviet Arctic since the 1930s. Scott and others (1959) concluded that about 2,000 to 2,500 polar bears existed near the Alaskan coast. By extrapolation they arrived at a total polar bear population of 17,000 to 19,000 animals. Uspensky (1961) estimated the world polar bear population at 5,000 to 8,000 animals. Harington (196+) has given an estimate of 6,000 to 7,000 polar bears for the Canadian Arctic and believes the world polar bear population is well over 10,000. Approximately 18 percent of the total Canadian Arctic population is cubs (0-2 years old).”[1]
“Some problems confronting polar bear research involve:
1. Establishment of confident population estimates.
2. Establishment of major patterns of population movement.
3. Collection of other data necessary for a life equation of the polar bear.
4. A thorough study of polar bear reproductive biology and population limiting factors under natural conditions.
5. Development of a reliable aging technique for polar bears.”[2]
“I. That the Canadian Wildlife Service reinvestigate a cooperative effort with the provinces of Manitoba, Ontario, and Quebec to ascertain a minimum polar bear population for the Hudson Bay region by simultaneous aerial survey work in autumn.
2. That efforts be made to investigate patterns of polar bear movement in the Hudson Bay region by using a wide spectrum of marking devices and techniques.
3. That the Bear Bay area of Devon Island be examined as a possibly common denning area for polar bears.”[3]
United States Report
“The number of polar bears in areas adjacent to Alaska is unknown. Sows with newborn cubs occur less frequently than would be expected in a typical population. An overharvest of bears adjacent to Alaska is not indicated by studies of biological data from animals killed by hunters.”[4]
Two polar bears in the distance, photographed by Steve Hillebrand USFWS pictures of polar bears
Proceedings of the 2nd Working Meeting of Polar Bear Specialists, 1970:
“Discussions centered primarily on population movements, denning areas, discreteness of populations, and, to a lesser extent, harvest figures, productivity, and density and abundance of the species throughout its circumpolar range. While insufficient data were presented to estimate the abundance of the species~ some agreement emerged concerning movements of polar bears, the discreteness of certain populations and other matters.”[5]
“Dr. Vibe stressed the importance of gaining much more knowledge about climate and sea ice conditions in order to understand both the movements and population size of polar bear populations. This, he felt, is of primary importance in understanding population dynamics in Greenland and may also be highly relevant in all arctic regions. He indicated that polar bear research in Greenland has been hampered by lack of staff and funds but that he hopes to launch a tagging programme in 1971 in co-operation with scientists in Norway and Canada.”[6]
The Polar Bear Situation in Greenland, by Dr Christian Vibe:
“The actual increase in harvest figures must be considered along with the present alternation of the whole climatical and ecological situation in the Arctic. The Arctic regions are more Continental today. Thirty years ago they were more Atlantic. The ecological conditions of the Arctic have changed as a result of this alteration of the climate. Some high Arctic regions get colder winters and less open water in summer. The productivity of the sea decreases in the Arctic and increases in regions nearer the Atlantic. The ringed seal moves to the areas of higher productivity and the polar bear follows the seal This is the situation to-day in Northwest as well as in Northeast and Southeast Greenland. All other animals in Greenland, in the sea as well as on land, are affected by the same climatical fluctuations, which are reflected in a regular shift between Arctic and Atlantic conditions (or Continental and Atlantic) over a period of 56 to 66 years; they are more marked every second time the period culminates. The climatic situation of today, with intense movements in the drift ice in summer is very similar to that 110-120 years ago. For the polar bear, especially in East Greenland, that means unstable living conditions, more roaming and probably greater loss of animals by drowning in scattered drift ice off South Greenland. Under the Atlantic conditions of forty years ago, the drift ice from the Polar Basin kept moving throughout the winter and melted at high latitudes in summer. The situation for the polar bear was quite the opposite to that of today. It then had to go ashore early in summer at high latitudes and fewer got lost. Alternatively, we could say that the polar bear probably was more numerous 30-40 years ago, as all Arctic animals were, but the Arctic Continental climate of today has forced it south to regions with unstable drift ice conditions and within the range of man.”[7]
“From ancient times the Thule eskimos used to go to the northern part of Kane Basin to hunt bears in the immense fields of grounded iceberg in front of the Humboldt glacier, where seals were numerous along the tide water cracks of' the grounded icebergs. But in the last few years these icebergs have disappeared—and with them the seals and bears. The colder climate has stopped iceberg production from the glacier and gradually the grounded bergs have drifted away without being replaced by new ones. The seals and the polar bears then left the area for the
eastern coast of Ellesmere Island where the bear is now hunted by the eskimos along the ice edge south Pim Island from 78° south to 77º. In later years the bear seem to have become more numerous here.”[8]
“Today most polar bears are found on the Canadian side of Baffin Bay. In the middle of the Inst century, bears were also numerous on the Greenland side. It is not known why the bear nowadays prefer the west coast of Baffin Bay. Melville Bay on the Greenland side is still a desolate area, the hunting has not increased and hunting from motorboat and ship in Melville Bay is prohibited. A possible explanation may be that old breeding ringed seals stay north. The young winter seals are mostly visitors from west and north - and the bears prefer to stay with the old breeding seals. But why do old breeding ringed seals occur in Melville Bay in smaller numbers than in the last century? We know too little about the ecological situation in Melville Bay to give an answer.”[9]
“Previous to 1950 most of the northern bears managed to stay in the north without drifting southwards, but to•day this situation seems to be different. Many bears, including females with cubs and pregnant females, are observed nowadays at Scoresbysund and south to Angmagssalik and Cape Farvel. It is quite clear that most of these animals have gone astray from their normal habitat and are facing difficulties which may result in their death. Cases where many bears are seen crowded in small area may be examples of similar situations.”[10]
“The bears on the drift ice are said to seek land when they wish to hibernate, or when the weather is bad causing strong movements in the sea ice. Coming ashore, the bears pass through the fjords to the land near the glaciers, where some of them hibernate.”[11]
Norwegian Polar Bear Investigation, by Dr Thor Larsen:
“Although observation data have not been thoroughly examined, it seems that polar bears are rather abundant in the eastern Svalbard summer pack. Evidently, it is a higher bear density there than off the Alaska coast in early summer.”[12]
“The marking/resighting/recovery data are not sufficient for statistical evaluation of the polar bear abundance in Svalbard.”[13]
“Mr Lönö states that there has been a decrease in the number of bears in Svalbard since the 1900s, probably somewhat less than 25%. His view is based on an evaluation of catch data from several regions (Lönö 1970).”[14]
“The drowning of bears which drift away with the pack ice is probably an important mortality factor. Vibe (1967) has shown a correlation between the polar bear abundance and pack ice conditions, what we also have observed on our summer expeditions to Svalbard. We noted that bears were often found close to the edge of the ice. When big icefloes or sections of the pack drift off, bears in that ice will most likely perish.
During the 1967 summer expedition, two dead polar bears were found in the pack, one by our expedition vessel and another one by ‘Fortuna’, a sealer trophy hunting in the same region. The bodies had no scars or bullet wounds, and a brief autopsy did not reveal the cause of death. Both bears were about 6 years old, and in fair condition.”[15]
Polar Bear Research and Conservation in Alaska, 1968-1969:
“We have attempted to census polar bears by making aerial counts in sampling areas from fixed-wing light aircraft. The method appears to be unsuitable for obtaining estimates of total numbers because it is difficult to see white bears against a white background and there is no way to determine how many bears are present in sampling areas and not seen (Lentfer, et. al. 1967). Infra-red photography or heat-sensing equipment will probably be used in the future as an aid in locating bears.”[16]
“Changes in abundance of bears in an area from year to year can be caused by differing ice conditions as well as by changes in population size.”[17]
Proceedings of the Third Working Meeting of the Polar Bear Specialist Group, 1972:
“Doubts were expressed over the reliability of polar bear census figures derived from counts from fast, high-flying aircraft over sea ice. Denning surveys undertaken from aircraft appear to be reliable, but it was desirable to check then by surveys on the ground. It was unfortunate that tho work on infra-red scanning devices for polar bear censuses had been suspended because of luck of funds as this technique was considered to have high potential for detailed aerial counts in bear concentrations areas.”[18]
“Considerable interest was shown in the polar bear population estimates for the Chukchi/Beaufort Sea area (4925 animals) based on a life table constructed from harvest data, and for the Svalbard region (1500-2000 animals) based on observation from ships under optimum weather conditions. Differing opinions were expressed
about the validity of applying a male survival curve to the female segment of the population and the likely period of heaviest juvenile mortality, but it was agreed that the construction of life tables was a very valuable means of providing new population estimates for the polar bear and should be pursued in countries in which harvest data is available.”[19]
“A total of some 850 polar bears have now been marked. The majority of marked bears recovered to date in Alaska, Canada and Norway had been found in the general vicinity in which they had been marked. It was agreed, however, that the home ranges of polar bears were vast and these preliminary data did not exclude the possibility of long distance, seasonal migrations in some regions. It was felt that if reductions in permissible harvests continued, returns from kills would obviously diminish and that there was a need for new tags that would be visible on living animals when viewed from the air. The Committee on Tagging agreed to re-examine this problem. Reports on telemetry methods of tracking bear movements in Alaska and Canada were favourable and, whilst technical problems still needed to be solved, extension of the use of this technique was considered to be highly desirable.”[20]
“Dr. Vibe presented further information on climatic fluctuations and changes in polar bear and seal harvests during past decades in Greenland. It was recommended that the possible influence of socioeconomic factors on these correlations should be examined in detail. It was also suggested that climatic fluctuations might affect bear distribution rather than absolute numbers, although if they prevented pregnant females from moving to denning sites, for example, then populations might well be depressed.”[21]
“In concluding this account of the proceedings of the Third Meeting of the Polar Bear Specialist Group, the opportunity is taken of placing on record IUCN's grateful thanks for the generous financial support accorded by the New York Zoological Society and by the American Conservation Association through the Conservation Foundation.”[22]
Alaska Polar Bear Research and Management:
“We no longer obtain data from hunting guides on the number of bears they see per unit of time spent flying over the ice. These data obtained through 1969 (Lentfer 1970) were not used to predict total numbers of bears within areas of observation, but, because they were somewhat comparable from year to year, were used as indicators of relative numbers. As regulations relating to hunting with use of aircraft have become more restrictive, pilot-guides have become less cooperative, and data obtained since 1970 are not considered reliable. Some guides have reported more bears than they have actually seen in order to weaken any argument for restriction of hunting with aircraft based on a reduced number of animals in the population.”[23]
“Composition of the hunter harvest (Tables 4 and• 5) does not indicate composition of the population because hunters select for single and larger bears. We have data through 1969 (Lentfer 1970) on composition of bears seen hut not harvested by hunting guides. We no longer obtain this type of data because some guides started giving false information as hunting regulations became more restrictive.”[24]
“Relationships between polar bears and sea ice were studied, with emphasis on possible effects of sea ice movements and climatic changes on polar bear distribution and movements off the Alaska coast (Lentfer 1972). Information was obtained from Eskimo hunters, snow-machine trips along the coast, aerial surveys made shortly after freeze-up in the fall and bear tagging flights. Ice movements could tend to isolate most bears to the west of Alaska from most bears to the north of Alaska, but, at the same time, provide for a limited amount of mixing of animals from the two areas. Long term warming and cooling trends occur in the Arctic and probably affect polar bear distribution and numbers. Climatic trends should be considered when assessing bear distribution and population data on a long term basis.”[25]
Polar Bear Investigations in Alaska:
“Despite various regulatory measures imposed during recent years to control or restrict the number of polar bears taken by Alaskan hunters, annual harvests have continued to be large in relation to abundance estimates given by Tovey and Scott (1957) and Uspenski (1968 and earlier). This situation continued to cause much concern among conservationists, both in and out of government. Determining bear movements and the relationship between regional stocks or populations necessarily has received top priority in our research activities, but sufficient progress in this area has been made”[26]
“Lentfer and his co-workers (Lentfer et al, 1967) attempted the direct counting of bears from a survey aircraft flying predetermined patterns over the ice pack, but concluded that the method was impractical because of an unknown proportion of the animals along the flight path were not seen.”[27]
Polar Bear Research in Norway:
“Attempts have been made to estimate the number of polar bears present in the Svalbard area. Data collected on aerial surveys over the eastern Svalbard pack ice in 1966 and 1967 and from the expedition vessels in the same general region in 1967 and 1968, have been evaluated and compared. Air counting success was shown to vary with weather and ice conditions. Airplane speed and altitude were the most important limiting factors for absolute counts. Observation distance, weather conditions, observers experience and degree of colour sense affected the ship counts. Ship counts were considered more reliable than airplane counts, but both methods are inaccurate. An evaluation of the counts made from ships under optimal conditions only, suggested that the total number of polar bears in the Svalbard area was between 1500 and 2000 in the late sixties. Comparison between air and ship counts showed a great discrepancy between the two counting methods. Absolute air counts of polar bears must be considered very unreliable. Previous worldwide estimates of polar bears are also unreliable, because of the lack of evaluation of the methods used, and because a census by one method in one particular area, cannot be used in a worldwide estimate. Merely by summarising the various national counts, which still must be considered inaccurate, one reaches the conclusion that the worlds total polar bear population is probably closer to 20,000 animals, than to the lower figures often suggested.”[28]
“Polar bear counts in Svalbard, studies of migratory patterns and analysis of harvest data suggest that the polar bears in Svalbard and the western Soviet Arctic probably belong to one common stock. It has been surprising, and rather unexpected, to find relatively few polar bear dens in Svalbard, in spite of considerable effort in certain regions. It is a question if the major denning areas for such a common bear population may be found in the Soviet Arctic, as Russian biologists expect about 150 to 200 polar bears to den in The Frans Josel Land/Novaya Zemlya area. In order to get more information about this problem, a one month field expedition to Svalbard is planned to take place between March 25 and April 30 this spring. The expedition will use two small fixed wing aircrafts with ski (Cessna 185) and search for dens in the eastern and north eastern Svalbard area. The planned work has also become increasingly urgent, because of the build up around the oil exploitation and development in the archipelago. For further information, see Application for a World Wildlife Fund Grant, no. 826/1971.”[29]
References
1. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 1st International Scientific Meeting on the Polar Bear, p 11.
2. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 1st International Scientific Meeting on the Polar Bear, p 11.
3. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 1st International Scientific Meeting on the Polar Bear, p 12.
4. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 1st International Scientific Meeting on the Polar Bear, p 13.
5. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 1st International Scientific Meeting on the Polar Bear, p 44.
6. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 2.
7. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 3.
8. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, pp 15-16.
9. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 16.
10. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 16.
11. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, pp 17-18.
12. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 18.
13. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, pp 18-19.
14. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, pp 18-19.
15. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 22.
16. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 22.
17. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 22.
18. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 24.
19. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 43.
20. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 2nd Working Meeting of Polar Bear Specialists , February 2-4, 1970, p 43.
21. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists , February 7-10, 1972, p 6.
22. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists , February 7-10, 1972, p 6.
23. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists , February 7-10, 1972, p 7.
24. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists , February 7-10, 1972, p 7.
25. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists , February 7-10, 1972, p 21, per US report
26. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists , February 7-10, 1972, p 23, per US report.
27. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists , February 7-10, 1972, p 33, per US report.
28. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists , February 7-10, 1972, p 40, per US report.
29. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists , February 7-10, 1972, p 40, per US report.
30. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists, February 7-10, 1972, p 61, per Norway’s report.
31. International Union for the Conservation of Nature and Natural Resources (IUCN), Proceedings of the 3rd Working Meeting of Polar Bear Specialists, February 7-10, 1972, p 63, per Norway’s report.
