Polar bear behavioral response to vessel surveys in northeastern Chukchi Sea, 2008–2014

Evaluating the impacts of anthropogenic activities on Arctic wildlife is a key issue in current management and conservation strategies. With global climate change, expanding shipping routes, and increasing industrial development in the Arctic, the polar bear (Ursus maritimus) faces new challenges to its survival. Polar bear behavioral response to vessel presence is not well-documented. During the 2008–2014 Chukchi Sea Environmental Studies Program (CSESP), polar bear occurrence and behavioral data were collected during summer–autumn vessel surveys. We examined polar bear occurrence and behavioral response to vessel presence by distance. During this study, 56,901 km of observation effort occurred from 3 survey vessels and 42 groups (50 individuals) of polar bears were recorded. Over half of the groups exhibited a behavioral response (i.e., vigilance or flee) including all groups of mothers with cubs. The mean distance at which bears responded to vessels (805 ± 648 m) was closer than the mean distance at which no response was observed (2,001 ± 1,368 m). Logistic regression analysis revealed that response was associated with distance and our model indicated the estimated distance at which 50% of the polar bears would exhibit a behavioral response to be 1,645 m. Our findings are relevant to assess potential impacts of increasing vessel activity in the Arctic and to assist in the development of effective monitoring and mitigation strategies for polar bears.