Information on Polar Bears (Ursus maritimus) for the Kara-Barents Sea Region
(coming out of the results of MMBI expeditionary research in Kara-Barents Region in 19962003) Aim. Marine mammals and polar bear investigation is an integral part of the regional ecological expertise. It is connected with the fact that consumers of the highest order reflect integrally the state of other components of marine biota: phyto and zooplankton, ichthyo-fauna. But together with this birds and animals of the Arctic in their turn are sensitive indicators of the environmental changes. Intensive exploration of the Arctic Seas connected with the shipping development along the Northern Sea Route (NER), reconnaissance and exploration of the oil-gas bearing fields on the Kara and Pechora Seas shelf (submarine oil-gas pipe-lines laying, installation of drilling platforms and compressor stations, equipment of the technical systems and their providing etc.), will of course affect the Arctic ecosystems including highest vertebrate animals. In connection with this a complex monitoring of the Arctic mammals seems to be actual at the moment. In this paper the observations results of the MMBI RAS scientists on the polar bears along the Northern Sea Route course are presented (Fig. 1). These observations were conducted on board the atomic ice-breakers "Taimyr", "Vaigach", "Yamal", "Sevmorput", "Soviet Union", "Russia", "Mikhail Somov", "Arctic" and motor ships "Captain Danilkin", "Ivan Papanin", "Yury Dolgoruky" in 1996-2000 (Matishov et al, 2000) and in 2002-2003.
Fig. 1. Occurrence of the polar bear along the Northern Sea Route in 1996-2003 (on the data of the MMBI scientists obtained on board of the Murmansk Shipping Company vessels) 1
Materials and methods. In the west sector of the Russian Arctic the Northern Sea Route course is laid through the Barents, Pechora, Kara Seas. The last two seas are of special interest from the point of view of the investigations of distribution and abundance accounts of marine mammals and polar bear, as they are practically the whole year round excluding summer are covered with ice. Regularly similar investigations have not been carried out for many years, and it is necessary to fill the gap in the studies of the poikilotherm animals in this region. Investigation of the winter-spring distribution of the polar bear along the Northern Sea Route was carried out on board the Atomic ice breakers of the Murmansk Shipping company. In 1996 sea birds and mammals investigations were episodic, and since 1997 observations for the highest vertebrates in the Kara-Barents Sea Region are constant. Usually mammals account was conducted from the upper bridge of the ice-breakers applying 8-folds optics both: by the ship’s movement and at the monitoring stations. Zone of the account by the movement of the ship was 100-500 m, depending on the weather conditions. Together with this planned helicopters flies along the course of the ships movements were also used for the observations on the marine mammals (Matishov et al, 2000). Results. Ecological geographical and biological peculiarities of the polar bear in the Kara-Barents Sea Region Climatic and hydrological conditions in the winter-spring period in the in the south-eastern part of the Barents Sea and in the south-western part of the Kara Sea determine in many aspects biological peculiarities of the polar bear and their ecologo-geographical characteristics. Biotopic association to the ice structure In connection with the important role of the ice fields structure in the polar bears life in the MMBI expeditions along the Northern Sea Route ice conditions were obligatory registered. In spring 1997 polar bears and their traces occurred more frequently on the thin 1 year white ice (ice thickness is 30 - 70 cm) (Fig. 2) and on the white thin fine-broken ice (Fig. 3), more seldom - on the grey white ice (ice thickness is 15 - 30 cm ) (Table 1). Table 1 Polar bears occurrence in the areas with different type of the ice, % Ice conditions IV Gray ice Gray-white ice Thin white ice Average ice Thick ice Fast ice 33.3 66.7 1997 II-III 3.3 46.7 50.0 IV 23.8 33.3 42.9 1998 II-III 33.3 27.8 11.1 16.7 11.1 1999 V 8.3 25.0 66.7 II 100.0 2000 IV 100.0 -
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Fig. 2. A female with the young one (bear cub) on thin one year white ice (photo by Yu. I. Goryaev )
Fig. 3. Polar bear on thin fine-broken ice (photo by Yu. I. Goryaev ) In winter period 1998 polar bears and their traces chains occurred most frequently on the thin one-year ice, more seldom - on white gray and gray (ice thickness is 10-15 cm ). In spring period 1998 the majority of polar bears and their traces was registered on the thin white one year 3
ice, less on the gray-white and gray ice. In February 2000 all the animals and their traces chains were observed on the gray-white ice only. Dependence noticed between the polar bears distribution and ice formation structure corresponds upon the whole to the data obtained from other Arctic areas (Belikov et al., 1989) and confirms the general biotopic regularity of the association of the animals (including pinnipeds) to the areas with a large number of cracks and areas with water. At the same time it is necessary to note a significant impact of climatic factors on the dependence pointed out: a severe winter 1998/1999 influenced the polar bears vital activity conditions (zones of average, thick, one year ices and fast ice), during a "warm" winter 1999/2000 in February the animals were registered mainly on the areas with the gray-white ice. Polar bears behavior observations in connection with the life in ice are of special interest. In one of the expeditions (atomic ice-breaker "Russia", April 12 - May 04 2000 .) a very unusual way to overcome the thin ice area by a polar bear was registered. Running away from the icebreaker the animal found itself on the ice which could not have endure its body weight, thus, it threw itself flat and pushing from the ice by all paws, crept through a dangerous area rather quickly (Fig. 4). (Matishov et al, 2000).
Fig. 4. Polar bear crosses an area of the thin ice (photo by Yu. I. Goryaev ) Migrations During MMBI expeditions along the Northern Sea Route into the Kara-Barents Sea Region together with the accounts of polar bears abundance and their biotopic association to the ices of different structures both: direction of the animals themselves and orientation of the discovered on the ice traces chains were determined (Fig. 5). In spring 1997 in the polar bears movements and traces chains orientation there prevailed northern (33.3 %) north-eastern (38.1 %) and eastern directions (14.3 %) (n = 41). In 1998 together with these migrations movements of the polar bears to the west were noticed (20 % in February-March and 12% in April). And almost half of the animals (44.0 %) moved to the north (n = 25) in April 1998. 4
In February-March 1999 like in winter spring periods 1997-1998 animals movement priority to the northern (28.7 %), north-eastern (14.3 %) and eastern direction (29.8 %) (n = 84) remained, though in May together with these migrations (correspondingly 16.7; 29.2; 12.4 %) almost a quarter of the animals (24.9 %) preferred western direction (n = 24). Analyzing the data during three years of observations (1997-1999) on the polar bears in the Kara-Barents Sea Region along the Northern Sea Route (Fig. 5), it might be concluded that the majority of the animals in winter-spring period migrate in the northern (28.5 %), north-eastern (23.4 %) and eastern (19.8 %) directions. More seldom the animals move to the west (13 %) and to the south-west (6.1 %) and practically do not use southern (4.0 %), south-eastern (3.2 %) and north-western (2.0 %) directions (Fig. 6) in this period of vital activity (Matishov et al, 2000).
%
45 40 35 30 25 20 15 10 N NE E SE 0 S SW W NW
To ta l Fe br ua ry M ar c h Ap ri l M ay
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direction
Fig. 5. Movement directions of the polar bears and orientation of their traces chains in winter-spring period 1997-2001 in the south-eastern part of the Barents Sea and in the south-western part of the Kara Sea .
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Fig. 6. Generalized results of polar bears movements and orientation of their traces chains (n=209) in winter-spring period 1997-1999 in the Kara-Barents Sea Region (along the Northern Sea Route) Distribution The majority of the scientists consider that the polar bears density in the Kara-Barents Sea Region is determined to the greatest extent by the ice conditions (Gorbunov et al., 1987; Belikov, Gorbunov, 1991). This opinion is confirmed by our data on the polar bear distribution along the Northern Sea Route in winter spring period (Table 2). Thus, in February 2000 over the whole course of the route only 2 adult animals were registered from board the atomic ice-breaker "Taimyr" and in February 1999 г. - 36 specimens, which is well correlated with ice conditions of each year. In 1999 thin gray white ice and average prevailed on the Northern Sea Route, fast ice and hummocks also occurred. During the cruise of the atomic ice-breaker "Taimyr" about 57 % of the route were in the conditions of the fine-broken and continuous young (the age is not more than several days) of the gray-white ice nilases 10-15 cm thickness, which is little used by the seals, the major food components of the polar bears. Table 2 Average density of the polar bears settling along the Northern Sea Route according to the ship-accounts during MMBI cruises on board the atomic ice-breakers from the Murmansk Shipping Company Area Barents Sea (south eastern area) Year (month ) 1997 (April) 1998 (April) 1999 (February-March ) 1999 (June-July ) 2000 (February) 1997 (April) 1998 (April) 1999 (February-March ) 2000 (February) 1999 (June-July) Density of settling, specimens per 1 000 km2 1.6 1.7 4.9 5.0 6.6 18.0 0.007 5.7 6
Kara Sea (South western area )
A high density of polar bears in the south-western part of the Kara Sea in 1997-1999 ( 5.0 18.0 specimens per 1000 km2) in comparison to the average data on the animals settling in the Kara Sea (0.43), is quite probably conditioned by the peculiarities of the ships’ leading along the Northern Sea Route. Usually the ice-breakers’ course is laid in the fractures of the ice fields and «polyn’yas», that is areas rich in life to the largest degree. Taking into consideration a relatively narrow transect of the observations (not more than 6 km in fine weather), it is quite natural to suppose that the indices of the average density of the animals settling will be higher if the accounts carried out from board the ship in comparison to air reconnaissance data (per unit of area). (Matishov et al, 2000). Sex and age composition Winter-spring observations of the MMBI scientists on the polar bears in 1997-1999 allowed to obtain the data on the sex-age composition of separate groups of animals in the KaraBarents Sea region along the Northern Sea Route (Fig. 7). Analysis of these data testify to the proportional decrease of the small bears and the females with the young bears due to the increase of the number of single animals in the period February-April-May. In average during the whole observation period along the Northern Sea Route the females ( with the young) constituted 14 %, the young - 28 %, single polar bears – 58 %. The obtained data on the polar bears age composition are close to those of the generalized observations (during the whole year ) in the polar stations. In accordance with them among the total number of polar bears (561) - single animals are 63 %, females with the young of different ages - 16 % and the young bears - 21 % (Karlovich, 1969). Together with this our data for 19971999 are comparable with the results of the air accounting works in April-May 1962, 1967 and 1968.: among 58 animals 71 % are adult single animals, 12 % - females with the young of different ages, and 17 % - the young. And in the Barents Sea the females with the young of different ages constitute about 14%, in the Chukchee Sea is approximately - 33 % (Uspensky, 1989).
Fig. 7. Dynamics of the young bears (1), females with the young (2) and other animals groups occurrence (3) along the Northern Sea Route in winter-spring 1997-2000
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At the same time it is necessary to note that in other conditions (season of the year, geographical situation of the region, ice situation) the polar bear population age composition might differ significantly. Thus, near the Alaska coast in March-April 1948-1965 among 3329 registered specimens 47 % were the adult single animals, 20 % - females with the young - less than 1 % - females with the young at the age 0+, 31% - the young and only 1 % - the young at the age 0+. But during special air accounts carried out here in April 1966, near the «polyn’yas» mainly among 33 registered animals adult single bears constituted only 39 %, females with the young constituted 6 %, females with the young of the age 0+ were - 15 %, the young were - 12 % and the young at the age 0+ were - 27 % (Polar Bears - IUCN, 1972, 1976). Significant differences from our data as far as the age structure of the animals from the southern part of the Kara-Barents Sea Region are revealed in the Franz-Josef Land area, too. In spring period the small polar bears at the age 0+ constituted here 33-36 % of the population, the females accompanying them - 18-19 % and the animals of different age-sex groups - 46 % (Parovshchikov, 1967). It was pointed out earlier to the negative effect of the anthropogenic factors including the hunting on the polar bears. But the arrangements on the protection of these rare Arctic animals might destroy the compiled during the century age and sex ratios in different ecologogeographical - animals groupings. Thus, in the Spitzbergen area there were noticed (Larsen, 1985) changes in the polar bears structure in connection with its complete protection: decrease of the number of progeny and a higher mortality of small bears, which might be connected with the increase of the number of adult males, which earlier were caught first of all (Matishov et al, 2000). Thus, during MMBI investigations ecologo-geographical and biological peculiarities of the polar bear inhabiting in the Kara-Barents Sea Region were revealed and generalized. The polar bears studies in this area will be proceeded. References Belikov S. E., Gorbunov Yu. A. Distribution and migrations of the polar bear in the Soviet Arctic in relation to ice conditions // Proc. of the Tenth Working Meet, of the IUSN/SSC polar bear specialist group. 1991. № 7. P. 70-74. (in Russian) Gorbunov Yu. A., Belikov S. E., Shilnikov V. I. Ice conditions impact on the distribution and abundance of the polar bear in the Soviet Arctic Seas // Bull. MSIN. Dep. Biol. 1987. V.92, issue 5. p. 19-28. (in Russian) Karpovich V. N. Polar bear location in the Soviet Arctic according to the data of the correspondent network // Polar bear and its protection in the soviet Arctic. Л.: Hydrometeoizdat, 1969. p..68-88. (in Russian) Larsen T. Polar bear denning and cub production in Svalbard, Norway // J. Wildlife Manag. 1985. V.49, № 2. P.945-960. Matishov G.G., Mishin V.L., Yerokhina I.A., Vorontsov A.V., Goryaev Yu. I. Polar Bear (results of MMBI's marine expeditions at the Kara-Barents region in 1996-2000). Murmansk: MIP-999, 2000. 70 p. (in Russian) Parovshchikov V. Ya. Polar bear on the Franz-Josef Land // Problems of the North. M.: Nauka, 1967. Issue II. p.149-159. (in Russian) Polar Bears. Proc. of the 3-d Working Meeting of the Polar Bear Spec. Group, organiz. by the Survival Service Commis. of IUCN 7-10 Febr. IUCN Publ. New Ser. Suppl. Pap., 1972. № 35. P. l-97. Polar Bears. Proc. of the 5th Working Meeting of the Polar Bear Spec. Group, organiz. by the Survival Service Commis. of IUCN, held at Le Manoir St-Prex, Switzerland, 3-5 Dec. 1974. IUCN Publ. New Ser., Suppl. Pup., 1976. № 42. P. 1-106. Uspensky S. M. Polar bear. M.: Agropromizdat, 1989. p.85-86. (in Russian)
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