Kodiak Brown Bears

Kodiak Brown Bears
		by *Victor G. Barnes, Jr.* National Biological Service *Roger B. Smith* Alaska Department of Game and Fish *Mark S. Udevitz* National Biological Service *Jay R. Bellinger* U.S. Fish and Wildlife Service
Brown bears (Ursus arctos middendorffi) on the Kodiak Archipelago are famous for their large size and seasonal concentrations at salmon streams. Sport hunting of Kodiak bears has been popular since World War II. Their value as captivating subjects to observe or photograph is a more recent development that is increasing rapidly; visitors from around the world come to experience brown bears on Kodiak, adding substantially to Alaska's economy.

		Adult brown bear on Dog Salmon Creek, Kodiak National Wildlife Refuge, Kodiak Island, AK. Courtesy D. Menke, USFWS
An equally important contribution of brown bears is their value as an indicator of ecosystem vitality. Despite high population numbers, Kodiak bears are vulnerable to the environmental effects that have seriously depleted brown bear populations in Europe and parts of North America (Cowan 1972; Servheen 1990). They are long-lived mammals that require large expanses of land to meet biological needs, and their low reproductive rate limits population recovery. Energy development, depletion of salmon resources, and recreational growth are factors that can adversely affect bears and, in doing so, signal a loss of environmental quality affecting many species.

Management of Kodiak brown bears is directed at maintaining current density, distri-bution, and habitat-use patterns. This goal is challenged by growing levels of commercial and private use throughout the region. An immediate concern is cabin and lodge development on 121,500 ha (300,000 acres), formerly part of the Kodiak National Wildlife Refuge, that were deeded to Alaska Natives via the Alaska Native Claims Settlement Act. Much of that Native-conveyed land is coastal or riparian habitat especially important to brown bears during summer and fall. Concurrently, recreational use of the Kodiak refuge is increasing about 10% annually (USFWS 1987). Sport fishing, bear photography, and deer and elk hunting often put bears and humans in direct conflict (Smith et al. 1989).
Timber harvest on Afognak Island, uncertain trends of salmon populations due to natural or human-caused events (e.g., Exxon Valdez oil spill), and hydroelectric development (Smith and Van Daele 1990) could impose additional long-term effects on localized bear populations.
Population Monitoring
Sport harvest records, available since 1950 (Troyer 1961), provide the most comprehensive information on Kodiak brown bears. In addition, biologists use aerial surveys to monitor population and habitat-use trends of brown bears on southwest Kodiak Island, an area that supports the highest bear densities and approximately 15% of Kodiak Island's bear population (Barnes et al. 1988).
We assessed status of the Kodiak bear population from estimates of density for representative study areas on northern, southwestern, and eastern Kodiak Island. We radio-collared a sample of bears on each area and estimated bear density using ratios of marked and unmarked bears observed from small aircraft (Miller et al. 1987). Brown bear abundance on other geographic units of the Kodiak Archipelago was estimated by comparing those units with the study areas.
Status and Trends
Sport Harvest Records

Excessive and localized harvest of brown bears in the mid-1960's (Fig. 1) prompted biologists to impose restrictions (season length, area closures) that dramatically reduced harvest. A sharp rise in hunting in the early 1970's produced another increase in harvest. In 1976 the Alaska Department of Fish and Game began an area permit system that distributed hunting more equitably throughout the archipelago. Since 1980 the harvest pattern has been relatively stable, with an average annual take of 163 animals (Fig. 1).

Fig. 1. Annual sport harvest of Kodiak brown bears, 1961-93.

Sex composition of the sport harvest has remained relatively stable despite fluctuations in yearly harvest. From 1987 to 1993 the female portion of the harvest has ranged from 32% to 38%.

Age and skull measurements of harvested bears provide further evidence of population stability. Mean ages of males and females taken during 1981-93 (7.3 and 7.4 years, respectively) were slightly higher than during 1969-80 (6.3 and 6.8 years, respectively), but we attribute this difference to sampling variation (Fig. 2). Skull measurements (length plus width) of harvested bears, which generally indicate bear size (Glenn 1980), have remained consistent over time.

Fig. 2. Mean age of Kodiak brown bears harvested by sport hunters, 1969-92.

Collectively, sport hunting records point to a stable bear population on the Kodiak Archipelago. A comparison of average annual harvest and estimated population size indicates that harvest is at or near the maximum sustainable level (Miller 1990), and managers should closely monitor additional effects on the bear population arising from increased mortality or other factors.
Aerial Stream Surveys

Adjusted maximum counts from stream surveys ranged from 47 to 87 bears per survey over the past 12 years, but there has not been any consistent trend in the counts during this period (Fig. 3). The stream survey counts are used as an index to population size, but they are affected by many other factors such as timing of the surveys relative to peak bear concentrations and strength of salmon runs.

Fig. 3. Maximum counts from aerial surveys of brown bears concentrated along salmon-spawning streams on southwest Kodiak Island, 1982-93.

We consider estimates of composition based on the stream surveys more reliable. Annual estimates of the proportion of maternal females have varied little from the overall mean of 24% during this period. Taken together, the count and composition data suggest that the brown bear population in this area remains relatively stable.
Population Abundance
Estimates of brown bear density on three study areas on Kodiak Island ranged from 0.29 to 0.35 bears/km² (0.75 to 0.91 bears/mi²). Habitats represented by the areas included precipitous mountain terrain, shrub-covered slopes, riparian zones, coastal habitat, and extensive bog and heathland flats. Extrapolating those density estimates to comparable habitats on other geographical areas provided an estimate of 2,842 bears for the Kodiak Archipelago or about 0.23 bears/km² (0.60 bears/mi²). Bear density was highest at Karluk Lake (0.42 bears/km² [1.09 bears/mi²]) and lowest on small, isolated islands (0.04 bears/km² [0.10 bears/mi²]).
Management Considerations
Available information suggests that the status of the Kodiak brown bear population is better now than in some earlier periods. In the early 1900's bears were commercially hunted for their hides or indiscriminately killed as competitors of fisherman and ranchers (Troyer 1961; Smith et al. 1989). During the 1960's bears were killed in a controversial control program undertaken to reduce conflicts with livestock on northeast Kodiak Island (Eide 1965), and excessive sport harvest occurred on parts of southwest Kodiak Island. These events undoubtedly affected bear distribution and abundance in local areas. However, future management of brown bears and their habitat will face new problems, including accelerated timber harvest, construction of cabins on bear habitat, and additional hydroelectric development. Added to all these threats is the long-term problem of expanding recreational use. Effective management of the bear population in upcoming years will depend on inventory methods that can detect population change in a timely manner.
		For further information: Victor G. Barnes, Jr. National Biological Service Alaska Science Center Kodiak Field Station Kodiak, AK 99615

References
Barnes, V.G., Jr., R.B. Smith, and L.J. Van Daele. 1988. Density estimates and estimated population of brown bears on Kodiak and adjacent islands, 1987. Report to the Kodiak Brown Bear Research and Habitat Maintenance Trust. U.S. Fish and Wildlife Service and Alaska Department of Fish and Game, Kodiak. 34 pp. Cowan, I.M. 1972. The status and conservation of bears (Ursidae) of the world--1970. Proceedings of the International Conference on Bear Research and Management 2:343-371. Eide, S. 1965. The nature of brown bear predation on cattle, Kodiak Island, Alaska. Proceedings of the Conference of Western Association of State Game and Fish Commissioners 45:113-118. Glenn, L.P. 1980. Morphometric characteristics of brown bears on the central Alaska Peninsula. Proceedings of the International Conference on Bear Research and Management 4:313-319. Miller, S.D. 1990. Population management of bears in North America. Proceedings of the International Conference on Bear Research and Management 8:357-373.	Miller, S.D., E.F. Becker, and W.B. Ballard. 1987. Black and brown bear density estimates using modified capture-recapture techniques in Alaska. Proceedings of the International Conference on Bear Research and Management 7:23-35. Servheen, C. 1990. The status and conservation of the bears of the world. International Conference on Bear Research and Management Monograph Series 2. 32 pp. Smith R.B., V.G. Barnes, Jr., and L.J. Van Daele. 1989. Brown bear-human conflicts in the Kodiak Archipelago, Alaska. Pages 111-119 in M. Bromley, ed. Bear-people conflict: Proceedings of a Symposium on Management Strategies. Northwest Territories Department of Renewable Resources, Yellowknife, Canada. Smith, R.B., and L.J. Van Daele. 1990. Impacts of hydroelectric development on brown bears, Kodiak Island, Alaska. Proceedings of the International Conference on Bear Research and Management 8:93-103. Troyer, W.A. 1961. The brown bear harvest in relation to management on the Kodiak Islands. Transactions of the North American Wildlife and Natural Resources Conference 26:460-468. USFWS. 1987. Kodiak National Wildlife Refuge, final comprehensive conservation plan, wilderness review and environmental impact statement. U.S. Fish and Wildlife Service, Anchorage, AK. 533 pp.

References

Barnes, V.G., Jr., R.B. Smith, and L.J. Van Daele. 1988. Density estimates and estimated population of brown bears on Kodiak and adjacent islands, 1987. Report to the Kodiak Brown Bear Research and Habitat Maintenance Trust. U.S. Fish and Wildlife Service and Alaska Department of Fish and Game, Kodiak. 34 pp.

Cowan, I.M. 1972. The status and conservation of bears (Ursidae) of the world--1970. Proceedings of the International Conference on Bear Research and Management 2:343-371.

Eide, S. 1965. The nature of brown bear predation on cattle, Kodiak Island, Alaska. Proceedings of the Conference of Western Association of State Game and Fish Commissioners 45:113-118.

Glenn, L.P. 1980. Morphometric characteristics of brown bears on the central Alaska Peninsula. Proceedings of the International Conference on Bear Research and Management 4:313-319.

Miller, S.D. 1990. Population management of bears in North America. Proceedings of the International Conference on Bear Research and Management 8:357-373.

Miller, S.D., E.F. Becker, and W.B. Ballard. 1987. Black and brown bear density estimates using modified capture-recapture techniques in Alaska. Proceedings of the International Conference on Bear Research and Management 7:23-35.

Servheen, C. 1990. The status and conservation of the bears of the world. International Conference on Bear Research and Management Monograph Series 2. 32 pp.

Smith R.B., V.G. Barnes, Jr., and L.J. Van Daele. 1989. Brown bear-human conflicts in the Kodiak Archipelago, Alaska. Pages 111-119 in M. Bromley, ed. Bear-people conflict: Proceedings of a Symposium on Management Strategies. Northwest Territories Department of Renewable Resources, Yellowknife, Canada.

Smith, R.B., and L.J. Van Daele. 1990. Impacts of hydroelectric development on brown bears, Kodiak Island, Alaska. Proceedings of the International Conference on Bear Research and Management 8:93-103.

Troyer, W.A. 1961. The brown bear harvest in relation to management on the Kodiak Islands. Transactions of the North American Wildlife and Natural Resources Conference 26:460-468.

USFWS. 1987. Kodiak National Wildlife Refuge, final comprehensive conservation plan, wilderness review and environmental impact statement. U.S. Fish and Wildlife Service, Anchorage, AK. 533 pp.

Kodiak Brown Bears

Population Monitoring

Status and Trends

Management Considerations