Post by grrraaahhh on Sept 5, 2010 21:24:29 GMT -9
The brown bears of Sakhalin and the Kuril Islands The Sakhalin Oblast is unique in Russia as it consists only of islands. The archipelago encompasses 40 islands, with a total area of 18,000 sq. kilometers. The largest ones are Sakhalin, Iturup, Paramushir and Kunashir. Brown bears are found only on these islands. There is unverified data about the existence of a small population of bears on the northermost Kuril island, Shumshu.
Many scientists would classify the Sakhalin population as a distinct sub-species. The animals on Sakhalin are overall similar to the Kamchatka bears and reach 500 kg and more, the skull is more elongated and the skull arches are not as wide. The color varies from straw to black.
Bear seasonal activity In the spring, when they emerge from their dens, a majority of bears head for the coastal zone. During the first half of April, all along the Southern coast of Sakhalin (and in the North at the end of April-early May), snow is melting and at the same time the snow on the upper belt of the coastal terraces under the forest cover can reach between 1 and 1.5 meters.
Brown bears occur everywhere on Sakhalin Island and on some of the Kuril Islands - Paramushir, Iturup and Kunashir. The southern and central parts of Sakhalin Island are mountainous, with Eastern-Sakhalin and Western-Sakhalin mountain ranges stretching in a north-south direction. The North-Sakhalin plain occupies the northern part of the Island; at Schmidt Peninsula, the northernmost point, the relief becomes mountainous again. Vast areas are occupied by Poronaiskaya, Muravyinskaya and Susunaiskaya valleys and the economically developed downstream flood plains of big and small rivers.
Iturup, Kunashir and Paramushir also stretch from north to south; their surface is characterized by sudden changes from plains to volcanic peaks 1,124-1,189 meters (33,720 to 35,670 feet) above sea level. Mountainous tundra covers the tops of the mountains. Iturup is the largest among the Kuril Islands. There are lots of lakes in its lower parts. Larches and bamboo undergrowth are dominant flora species in the forests. Overall there are 650 plant species in the Island that develop in formations similar to those of Sakhalin Island. Among the berry plants, crowberry, honeysuckle, dog-rose, cherry-tree and mountain ash are the most widely-spread. The southern part of the Island is covered with dark coniferous forests with their upper belt covered by dwarf Siberian pine. The dwarf Siberian pine runs down to the sea level and is found almost everywhere.
The environment of Kunashir is similar to that of Iturup, however dark coniferous forests are more widely spread, and flora and fauna are more diverse. There are no forests on Paramushir. Down the river valleys and along the lower mountainous belt, trailing varieties of alder and dwarf Siberian pine grow in abundance; the upper belts are covered with oceanic mountainous tundra.
Blueberry, cowberry, honeysuckle and mountain ash can be found there; and dog-roses are in abundance. There is not much information available about the earlier state of the habitats and the number of bears inhabiting the area. It is known that bears can be found almost everywhere on Sakhalin Island, especially in its northern part. In the south they inhabit Susunaiskaya and other valleys.
In the beginning of the last century the local population started to actively pursue agricultural and fishing activities; this entailed an increase in population and the number of settlements, as well as agricultural development of the flood lands.
In the 50s people began aggressive logging, primarily of coniferous forests; and the number and the area of forest fires have increased. However, since the area of agricultural land was insignificant, these activities did not negatively affect the bears and their habitat. We assume that human activities did not have a significant impact on the bear habitat till now.
Individual and Geographic Variability of Species
Now there are at least 3 or 4 bear populations in Sakhalin that differ in body size, skull structure, fertility, population density and size. There are several populations of bears that have different skull structure: these are the Schmidt Peninsula bears, the Eastern-Sakhalin mountain range bears and the Crillon Peninsula bears. Although the skull structure of individual species varies considerably, and craniological data alone is not enough to study an intraspecific structure, we consider it reasonable to rely on the characteristics of skull structure as one of the morphological characteristics of the brown bear populations.
Brown bears inhabiting Sakhalin and the Kurils are generally divided into two subspecies: the bear of Paramushir and the bear of Sakhalin, Kunashir and Iturup. Morphological characteristics of the bears differ depending on their sex, age and habitat. Lack of information precludes us from conducting an in-depth analysis of the taxonomic categories of the bears inhabiting the region. Bears come in different colors varying from pure black to dark sandy. Most bears in the island of Sakhalin have fur color varying from dark-brown to sandy. The proportions of bears of different colors is approximately as follows: dark-brown of various intensity with a touch of another color on the nape, shoulders, and back - 75%, blond, from goldish to sandy - 20%, dark, almost black - 5%. Generally, the color of Sakhalin black bears is determined as dark. On Paramushir Island brown and pale-yellow are the prevailing tints in the coloration of the bears’ body and legs.
On Iturup and Kunashir most bears are dark-brown with touches of blond fur on the head and shoulders. At the same time, the color of Iturup bears may vary from pale-yellow to brown-black and almost black. Animals with auburn and gold fur on the neck and shoulders are often found in Kunashir. Correlation between the bears’ color and their habitat is not very well studied; therefore it is not possible to describe typical color characteristics of the local bear populations.
The brown bear is the largest and most widely spread mammal among other land fauna species in Sakhalin Island.
In the hunting grounds in South Sakhalin, in Dolinsky and Anivsky districts bears weighing up to 400 kg (880 lbs) can be encountered. One such big bear was harvested in April 1977.
In 1979, the footprint of a bear’s hind leg 33 cm long and 20 cm wide (13.2 x 8 inches) was found in the drainage of the Firsovka River. The footprint was pressed 5 centimeters deep into rather dry soil. Judging by the prints and the distance between the front and hind legs, the bear was huge and, according to the hunters’ estimates, weighed about 450-500 kg (990-1100 lbs).
Some hunters reported that they saw bears weighing 400-450 kg (990-1000 lbs) in Anivsky district in 1979. One bear killed in the south of Sakhalin weighed 402 kg (884 lbs) without the digestive tract, lungs and larynx.
Bears inhabiting South Sakhalin are big, but at the same time rather well-proportioned. The head is big and heavy, with a wide forehead. The ears are quite small compared to those of continental bears, they are round-shaped and, in the wintertime are covered over with the head’s fur. The eyes are dark and very small; the bare part of the nose is quite big. The tail is very short and completely covered over with fur. The claws on the front legs are much longer than on the hind legs, their length is up to 8 – 10 cm (3.6 – 4.5 inches). There are 5 well-developed pads on the hind legs; the fingers are covered with hair. The rest of the foot is bare. The pads on the sole of the foreleg are also well-developed.
The skull of Sakhalin brown bear is big and heavy; it has a more oblong form, less high forehead, slightly longer nose bones and zygomatic arcs less wide compared to other Far-Eastern bear populations. Differences in the skull structure of males and females are pronounced. Females have a smaller and lighter skull; the crests and lumps on the skull are less prominent, the cranium is less compact.
In 1970 a bear was killed on the Crillon Peninsula whose skull was rated 68.53 points at the Moscow Hunting Trophy Exhibition, this was 3 point more than the World record set by Romania. Its color was dark-brown, occasionally brown-black with a dark violet-bluish tint. On the head, shoulders and back, there were touches of chestnut color. The legs were dark-brown or almost black.
Brown Bears Home Ranges
On the southern slopes of Sakhalin, under the canopy of dark coniferous forests or dwarf pine there are areas that offer favorable conditions for digging dens. On the Kuril Islands, however, it is difficult to make a den due to the islands’ small areas, high humidity and volcanic mountains. For this reason the bears here can hibernate both in dens dug in the earth and in mountain niches and caves, sometimes in groups of 2 or 3 bears. Bears can easily cross the Island in any direction to get to the denning site. Paramushir bears move from north to south in the spring and backwards in the fall between denning sites and food sources, however in the summer and fall, bears change their home ranges depending on food availability.
Sakhalin brown bears enter their dens at different times. When a bear starts hibernating depends on whether it has gained enough weight, as well as on the weather conditions.
In the north of Sakhalin Island, bears go into hibernation between October 20-25 and November 5-15.
In South Sakhalin, bears start hibernating between October 25-28 and November 15-18. On the Kuril Islands, bears go to dens in late November. On Kunashir Island, the denning period starts in mid-December, but some animals may never hibernate.
The time when bears start emerging from their dens also varies and depends on the location of the den and the current weather conditions.
Sakhalin bears leave their dens in April or May. Some animals may emerge from their dens much earlier. On March 5, 1990 a bear’s footprint was found during a survey made in the 1989 forest fire buffer-zone.
Female bears with their cubs emerge from dens later, usually when snow is melting in most areas. When the vegetation blooms, bears become active during the daylight hours.
During salmon spawning periods bears can be found near the rivers from 6 till 10 a.m. and from 5 till 10 p.m. In salmon spawning periods, some animals, especially females with cubs, are active during the day. On rainy and cloudy days, most bears stay near the rivers all day long.
In June, when the vegetation on the stream banks has grown as high as 1-1.5 m, the bears start laying paths. Typically, their paths lead to the areas that have access to water.
The number of paths in the areas most frequently visited by bears varies from 10 to 40 per square kilometer.
When food sources become abundant, the bears pursue a particular pattern of daily activities. In spring and fall, this pattern is not really precise, and later in autumn, before entering their dens, bears stay active during daylight hours.
Brown Bear Population Size
The main brown bear habitat on Sakhalin Island is represented by fir forests covering 22% of the forest-covered area. The average density of the bear population here is 0.2-0.26 animals per 1000 hectares. Larch forests (28% of the forest-covered area) are the second important habitat: the density here is 0.15-0.21 animals per 1000 hectares. Secondary communities of small reeds and bamboo with a share of larch, stone-birch and deciduous plants take up about 34% of the Island’s area; population density here varies from 0.12 in the northern part to 0.65 animals per 1000 hectares in the southern part of Sakhalin. Various wetland habitats are mostly found in the Poronai River drainage and along the east coastline of the northern part of the Island. Other types of plant communities and agricultural lands cover small areas and thus do not play an important role in bear life. Depending on food availability, the density of the brown bear population on Kunashir Island is 0.5-0.7 animals per 1000 hectares, on Iturup Island - about 0.1 animals; on Paramushir Island - 1 individual per 8.5 square kilometers, and on the coast of the Sea of Okhotsk on this island, in the area of the the whaling plant dump, 2 animals per 8.5 square kilometers (1.17 and 2.35 individuals per 1000 hectares respectively). In the gathering sites, 5 or 6 animals sometimes can be found together on one square kilometer. In the early 70s in the Anivsky District, Sakhalin Island, the density was 0.55 individuals per 1000 hectares, and in the Tymovsky District - 0.27 individuals. The average density in the eastern part of the Crillon Peninsula is 50 to 55 individuals per 70,000 hectares. In the vicinity of abundant food sources close to the seashore, up to 10 bears may concentrate on 1000 hectares, thus animal density depends on the availability of food.
Like in the other regions in the south of the Russian FarEast, population surveys on Sakhalin and the Kuril Islands are not done on a regular basis.
Therefore, information on the numbers of bears in the region is sketchy and approximate. In the late 60s the number of bears on Iturup Island was about 300. Paramushir Island is inhabited by over 200 bears, and about 30 bears are killed annually. Large numbers of bears were recorded on Paramushir in the previous years. In the early 60s, over 500 bears were recorded in Iturup, and about 120 bears in Kunashir.
Currently about 100 bears inhabit Paramushir, about 300 bears – Iturup, and 130-140 bears - Kunashir.
Estimates of the total number of bears are also contradictory. In 1959-1962 about 2,600 bears inhabited Sakhalin Island, but later this number decreased to 2,000 bears. The data on the number of bears registered in the same years is contradictory because no regular large-scale bear surveys have been conducted on the islands. A recent report on the number of brown bears in the Sakhalin Oblast in 1999 compiled by the Sakhalin Hunting Management Department estimates that the total number of bears on Sakhalin Island and the Kurils does not exceed 3,500 animals. In 1999, 217 hunting permits out of a quota of 400 bears were issued, but only 72 of these permits were used.
Food Sources for Sakhalin Bears
Sakhalin bears often change their home ranges. In the spring, after emerging from their dens, bears come to the southern slopes of the mountains where they dig out roots and bulbs. Later in May they come to the rivers and berry-fields attracted by dead fish and berries and nuts left from the previous year. By this time, roots and fresh sprouts start growing on the wet slopes warmed by the sun; the thawed ground makes it possible to dig out the roots of calla, butterbur and bear’s angelica. On the Kuril Islands, hot springs are vital in providing abundant food resources for the bears: plants grow there year round, and amphibians gather here for wintering. Bears often come to the seashore in search for sea mammmals and plants washed ashore. Long cold winters and chilly summers with winds and fog make it difficult for plants to grow on the islands, thus ice-free rivers and hot springs are vital for the bears in the springtime.
As the spawning season starts in May or June, most bears stay close to the spawning rivers. Fish is a major source of protein for bears in this area. After bears eat enough fish, they move to the berry patches or grasslands, ready to come back to the rivers later. This way, bear diet becomes nutritious and varied. In the fall (October-November), before hibernating, bears leave the streams banks and, feeding on berries and cedar nuts, slowly move to the denning sites. In the fall, Sakhalin bears move to the upper ranges of the mountains, and the Kurils bears move to mountainous habitats.
The nature of the Kurils bears migrations is similar to that of the Sakhalin bears but their type is different.
Lack of crops and fish force bears to leave the rivers’ banks. Normally, salmon provides enough food resources for Sakhalin and Kurils bears. Salmon enter to spawn into almost every large and small river in the region, so bears do not need to move back and forth in search for food. Since the area is not well developed and human population density is low, human activities have not significantly affected brown bear habitats. Only during salmon spawning periods bears may be disturbed by fishermen coming to the rivers. Aggressive fishing activities force bears out of the river banks, but in most cases bears just relocate to more quite sites and change their behavior. Waste from fish processing plants is a very important source of food for bears. On the other hand, high bear density near the waste disposal sites makes the animals an easy target for hunting and shooting.
The abundance, type and diversity of food determine the Sakhalin bears’ food chain; while widely found berries like blueberry, cranberry, mountain ash and wild rose together with the perennial herbs like calla, butterbur etc. found on all the islands of Sakhalin Oblast determine their feeding habits. As for protein-based food, the major sources are humpback and king salmon. Great volumes of fish entering the rivers to spawn provide bears with proteins. On the Kurils, sealife washed ashore are a good supplement to the bears’ diet. Bears in all areas feed on invertebrates, primarily earthworms.
In general the bears’ diet in different parts of the region is similar. The major components of the bear diet are roots and bulbs of perennials, nuts of dwarf Siberian pine and fish. However, some areas have certain peculiarities. For example on Paramushir Islands food resources are scarce. A few types of fruit and berry plants and perennial herbs, dwarf Siberian pine, fish and sea products washed ashore are the major components of the diet. On Iturup food is more abundant due to availability of cranberry, honeysuckle and Kuril wild cherry. In addition to these plants, actinidia and grapes can be found on Kunashir, and there are large areas covered by various perennials. On all of the islands bears scavenge sea mammals carcasses, seaweeds washed ashore, and flies’ maggots found on rotten garbage heaps. In spring and summer bears readily eat bird cherries and fresh bamboo sprouts.
In the springtime bears are likely to pick up any food, vegetable or animal, including carrion. This period usually lasts from early April to mid-May. Bears concentrate on the lower reaches of the rivers, on the seashore and areas where plants start growing early. During this period the bear diet consists of roots of perennial herbs, fresh sprouts, berries and nuts left from the previous year and invertebrates. In the summer and fall, their diet includes fresh berries and nuts and salmon, it is therefore rather high in calories. This period is critical for bears as the abundance of food sources help them prepare for hibernating and survive the springtime low availability of food. In the spring and early summer, the bear’s diet can be defined as vegetarian and in late summer and fall as mixed. Plants account for 95% of the Iturup bears diet. At the same time, on Paramushir and other islands there are sites where protein-based food accounts for 50% of the bears’ diet. Cannibalism is not typical of the island bear populations.
Reproductive Patterns of Bears
Brown bears start preparing for reproduction in June after the vegetation becomes green and salmons enter the rivers to spawn. After the bears recuperate from spring and scarce food, they concentrate in the typical mating sites close to the spawning rivers where they search for mates. The mating season lasts from June to August. During the mating season, bears are agitated; occasionally in groups of 6-9 bears, including 5-8 males. The males demonstrate their strength by fighting, and at the end of the day a female stays with one of the males while others stay nearby. During the mating season, the cubs leave their mothers, or the males drive them away. Attacks by males often result in the death of the cubs. Males are very active and pursue a female the whole period while she is in oestrus.
The cubs are born in January of February, the usual size of a litter is 1 to 3 cubs. The average litter size is 2.2 - 2.3 cubs. The fertility of the bears inhabiting Paramushir and Sakhalin varies considerably. On Sakhalin the most typical litter size is 2-3, while on Iturup and Kunashir – 1-2 cubs. The typical litter size varies within the territory of Sakhalin as well: in the north of Sakhalin, a female bear usually gives birth to 2 cubs, sometimes 1 cub, whereas in the south, she will bear 3 or even 4 cubs. According to some hunters, they observed 28 new born cubs and yearlings in 17 brown bears families in the Tym River drainage. Judging by the numbe of newborn cubs, the average fertility rate of one family was 1.5 cubs (1 to 3 cubs in a litter), and judging by the yearling number, the fertility rate was 2.0 (there were 2 young bears in each bear family). The average fertility rate was 1. 65 cubs.
Bears become sexually mature by the age of 3. A female bear can start bearing cubs at the age of 4.
The average interval between litters is 2 years, but there are exceptions. About 15% of female bears on Sakhalin produce cubs every year.
Bears of Sakhalin Oblast have their mating season from late June till mid-August.
The number of cubs born to one female varies depending on the area.
On Kunashir Island this number is usually 1 or 2, in the south of Sakhalin 2 or 3, sometimes 4, in the north of Sakhalin 1 or 2, sometimes 3, on Iturup and Paramushir 1 or 2, sometimes 3.
Characteristics of Commercial Bear Harvest
The hunters in South Sakhalin perceive the bear as one of the most desired objects of sports hunting, and every year more and more hunters try to get the desired trophy: a bear hide. Starting in 1981, a system of licensing hunting activities was introduced in Sakhalin Oblast. The cost of a hunting license is 420.79 rubles (about US$ 14). The introduction of the licensing system resulted however in an increased number of hunters.
In 2000, there were 19,000 hunters registered in the Sakhalin Oblast.
Only in July and August 1980, about 20 - 30 bears were killed on Paramushir. Bear hunting is less aggressive on Kunashir, where 10 - 15 animals are harvested annually. The most aggressive hunting is pursued on Iturup where 40 - 60 bears are killed annually. On all these islands, the hunters use firearms to kill bears. According to official data, in the last decade, a maximum of 20 bears are killed annually on the Kuril Islands. Usually the whole carcass of the killed animal is put to use.
About 100-150 bears are harvested annually in the Oblast. Due to the introduction of a licensing system, the number of animals killed annually has dropped; however the general population size remains at the same level as earlier. Professional hunters consider the period from middle April to early May, when bears have just left their dens, to be the best hunting season. Bears can be clearly seen, they are still quite fat and easy-to-kill. The promotion of spring hunting enables to conduct selective harvest and organize hunting tours for foreigners.
The Sakhalin bear is a big and valuable trophy. To preserve this traditional hunting resource, it is critical to impose limitations on the bear harvest and conduct annual bear population surveys to find out the sex-age structure of the population, especially on the Kuril Islands. At the same time it is advisable to increase the harvest quota by regulating the selective harvest of males and discontinuing the harvest of females.
There is an interesting fact worth mentioning. According to the information received in 2000 from N. Kolotilin, a hunter from the Severo-Kurilsky District, the bears from the Kamchatka Peninsula occasionally swim over to the small island of Shumshu in the northernmost point of the Kurils. As a result, now there is a small population of brown bears of about 10 individuals that migrated from Kamchatka to the northernmost island of the Kuril archipelago.
Bears inhabiting the region are peaceful animals. Bears typically are not aggressive towards other bears and humans. Occasionally some big males may be aggressive and attack domestic animals. There are no records of females with cubs attacking domestic animals. Once a bears discovers a good cattle-pen, it often visits it with extreme caution.
Since the food sources in Sakhalin are abundant, compared with the other Russian Far East regions, there is no competition for food among bears. This fact accounts for the following characteristics of the brown bear populations that inhabit the islands:
1) High population density; 2) No competition for food; 3) Tolerance of other bears at a close distance; 4) No records of wandering bears; 5) Several big bears can den together in a single den; 6) Bears are not very territorial;
The gathering of bears near food sources is also illustrative of their tolerance of other brown bears. Bears are also tolerant of humans in those cases when a bear accidentally encounters a human. Currently the number of bear-livestock conflicts in agricultural areas is increasing.
It is expected that, in the future, human-bear relationship in the north and the south of Sakhalin will become more complicated. First of all, there will be an increased number of human-bear conflicts due to a decrease in food resources on the territories modified by humans. One more factor that will negatively affect the bears is that some species (i.e. salmon) may fall out of the food chain, leading to a decrease in the number of species in the local groups. According to leading biologists and hunters, unless measures are taken to conserve brown bears, this species can become extinct in economically developed areas.
Although the brown bear population in the region seems to be healthy, nowadays bears are rarely encountered in the economically developed areas, and the Kuril population has decreased almost by half.