I systematically observed brown bear (Ursus arctos) and human activity on a sockeye salmon (Oncorhynchus nerka) stream in Katmai National Park during fall 1993 and 1995. More than 700 hours of observations were used to determine the temporal and spatial use patterns by people and bears as well as the frequency, nature, and outcome of bear-human interactions. Bears altered their temporal and spatial use of the river to accommodate human activity, seeking times and places where human use was lowest. Bear-human interactions were primarily the result of people venturing into areas of concentrated bear activity, rather than bears entering areas heavily used by people. Approximately one-fourth of bears involved in bear-human interactions left the river, not to return for several hours. Bears acted differently in river zones dominated by people than in zones dominated by bears in that they spent less time on the river, less time resting, and more time moving about in human-dominated zones. The data suggest that as long as there are areas where bears can avoid human activity, they will seek them to gain access to salmon. If, however, human use of the river continues to increase as it has the past decade, the day may come when there will be no more room for bears.
