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Estimates of brown bear abundance on Kodiak Island, Alaska

Ursus

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Abstract

During 1987-94 we used capture-mark-resight (CMR) methodology and rates of observation (bears/hour and bears/100 km2) of unmarked brown bears (Ursus arctos middendorffi) during intensive aerial surveys (IAS) to estimate abundance of brown bears on Kodiak Island and to establish a baseline for monitoring population trends. CMR estimates were obtained on 3 study areas; density ranged from 216-234 bears/1,000 km2 for independent animals and 292-342 bears/1,000 km2 including dependent offspring. Rates of observation during IAS ranged from 1.4-5.4 independent bears/hour and 2.9-18.0 independent bears/100 km2. Density estimates for independent bears on each IAS area were obtained by dividing mean number of bears observed during replicate surveys by estimated sightability (based on CMR-derived sightability in areas with similar habitat. Brown bear abundance on 21 geographic units of Kodiak Island and 3 nearby islands was estimated by extrapolation from CMR and IAS data using comparisons of habitat characteristics and sport harvest information. Population estimates for independent and total bears were 1,800 and 2,600. The CMR and IAS procedures offer alternative means, depending on management objective and available resources, of measuring population trend of brown bears on Kodiak Island.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Estimates of brown bear abundance on Kodiak Island, Alaska
Series title:
Ursus
Volume
10
Year Published:
1998
Language:
English
Contributing office(s):
Alaska Biological Science Center
Description:
pp. 1-9
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1
Last page:
9
Number of Pages:
9