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Distribution, abundance, and quality of forage within the summer range of the central Arctic caribou herdDistribution, abundance, and quality of summer forage available to caribou (Rangifer tarandus granti) of the Central Arctic Herd were determined in July and August, 1989 -1990. Plant cover, an index of available biomass, was measured at three sites within 50 km of the arctic coast. In general, plant cover increased with distance from the coast. Cover of forbs and evergreen shrubs was higher at inland sites (P < 0.001), whereas cover of willows (Salix spp.) was highest at the coastal site (P < 0.001). Higher plant cover inland is largely attributable to a greater proportion of drier habitats. Differences in forage quality among sites, however, were small and inconsistent. I conclude that by feeding inland during insect-free periods, caribou realize a net energy benefit, because of higher plant biomass, higher proportion of drier habitat, and greater species diversity than coastal areas.
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Evaluation of Arctic grayling enhancement: a cost per survivor analysisAge-O Arctic grayling Thymallus arcticus were stocked as sac fry and fingerlings in lakes in interior and south central Alaska to evaluate cost per survivor at age 1. When sac fry, 4-g, and 6-g fingerlings were stocked in the same lakes in 1986, estimates of the mean rate of survival at age 1 were 0.08, 0.63, and 0.75. The differences were significant. The mean costs per survivor at age 1 were $1.58, $0.24, and $0.21. The differences were significant between sac fry and both sizes of fingerlings. However, the difference was not significant between 4-g and 6-g fingerlings. When sac fry and 4-g fingerlings were stocked in different lakes in 1986 and again in 1987, estimates of the mean rate of survival to age 1 were 0.11 and 0.34. The difference was significant. The mean costs per survivor at age 1 were $0.82 and $0.70. The difference was not significant. I recommend stocking 4-g fingerlings because they require less rearing in a hatchery than 6-g fingerlings and the cost per survivor is usually less than that for sac fry.
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Effects of placer mining sedimentation on Arctic graying of interior AlaskaDuring summer 1982 and 1983, I assessed the effects of placer mining sedimentation on Arctic grayling, Thymallus arcticus, in the headwaters of the Birch Creek and Chatanika River drainages, northeast of Fairbanks, Alaska. In each drainage I compared the differences between two streams near their confluence, one that was undisturbed and one with mining activity upstream. Although many age-0 and adult grayling used unmined streams for summer habitat, I found no grayling in the mined streams except during periods of migration. Apparently, grayling consistently chose clearwater streams for summer residence. Caged fish studies demonstrated that if grayling could not escape from streams carrying mining sediments, they would suffer direct, chronic effects, including gill damage, dietary deficiencies, and slowed maturation. The indirect effects of sedimentation on grayling populations, through loss of summer habitat for feeding and reproduction, are more severe than the direct ones.
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Seasonal distribution and winter habitat use by Sitka black-tailed deer in the Prince William Sound region, AlaskaIntensity of winter use of a variety of forest stands by deer (Odocoileus hemionus sitkensis) was measured. Information on vegetation, timber type, and topography was collected to find relationships between deer use and habitat variables. Seasonal use of forest stands by deer is best described in terms of: basal area of trees, amount of deer forage (Vaccinium spp. and Coptis aspleniifolia)r deviation in crown closure, and timber volume. Information from radio-collared deer indicated high use of forest habitat, particularly during winter. Alpine areas received more use than any other habitat during summer. South-facing slopes were used more often than other aspects across all seasons. Average winter home range size was 160 ha, significantly smaller than the spring average (282 ha). Most radio-collared deer made seasonal elevational movements within a single drainage. Retention of high timber volume, old growth forest is recommended to maintain preferred deer habitat in Prince William Sound.
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Estimation of angler harvest, catch and effort in the Swanson River canoe trails system, Kenai National Wildlife Refuge, AlaskaMethods of estimating harvest, catch, angler effort and quality of catch were tested during the summer of 1988 on the Swanson River Canoe Trails System, Kenai National Wildlife Refuge, Alaska. Angler interviews at Trails System access points provided the best estimates of these sport fishing variables. Rainbow trout dominated the catch (95%); about three-fourths were less than 254 mm long and most were released. Total estimated catch of trout was 18,448 (10,221-26,675; ρ=0.95); estimated harvest was 25 percent of the catch: 4,651 (2,722-6,580; p=0.95). Aerial surveys (counts of cars and boats) and the trail head registers provided seasonal use trends for the Trails System, but there was no relationship between these indices and the variables of the fishery. Anglers must be personally interviewed in order to acquire data to evaluate the fishery.
