Interactions, injuries, and mortalities of killer whales (Orcinus orca) observed during fishing operations in Alaska

Fishery observer records from 2001 through 2016 were examined to document interactions, injuries, and mortalities of killer whales (Orcinus orca) associated with fishing operations in Alaska. Although widespread throughout Alaska, the highest numbers of such events occurred in the southeastern Bering Sea. Killer whales of the resident ecotype feeding on catch or discarded catch and fishermen using whale deterrence measures represented 96% (number of interactions [n]=3110) of all interactions examined in this study (n=3245). We found that 87% (n=2817) of all interactions occurred during longline operations. Both minor and serious injuries were documented. Twenty-seven killer whales were reported dead, but additional mortalities are assumed. Most whales killed were residents; however, 3 transient whales were also taken. Because killer whale populations are relatively small, a low level of mortality may significantly affect populations, especially if multiple sympatric stocks are shown to exist. Given the long history (i.e., over 6 decades) that Alaska killer whales have had with fishing operations, it is likely that these interactions will continue.