Attraction of polar bears Ursus maritimus to offshore drilling sites in the eastern Beaufort Sea

Wildlife observations recorded at several offshore hydrocarbon exploration sites in the Beaufort Sea were examined to evaluate the hypothesis that polar bears Ursus maritimus are attracted to drill rigs, will be judged to represent a threat to humans there, and consequently will have to be deterred or destroyed. When polar bears came south with the pack ice in the autumn, they approached drillships or artificial islands, probably because they became curious or were attracted by unfamiliar smells. However, these bears did not usually remain in the area.In late winter, when most of the natural leads are frozen, the movement of compacted annual ice from east to west past permanent offshore drill rigs creates open cracks on the downstream side. Because of the open water there, seals are more abundant, more accessible, or both, and bears are attracted because of better hunting conditions. In mid to late winter some bears may remain in the area for several days or longer while hunting seals. This positive reinforcement may lead these bears to be attracted to other offshore rigs in the future. In the last five years four bears attracted to offshore rigs have been shot; thus the hypothesis was found to be valid. To date, the population is not under threat, but this could change if the number of offshore drill rigs operating through the winter were to increase.