Killer Whales Disturbed by Boats
When boats appear in the vicinity, northern resident killer whales spend 18 percent less time feeding on salmon.
The British Columbian whales are not as likely to begin eating after boats arrive and whales already feeding are more apt to stop.
Researchers express concern that the reduced amount of time allocated to eating could harm the whales. Since insufficient prey is one threat to survival of the northern resident whales, having less time available for feeding could hinder the whales' ability to acquire enough food. Whales also exert 3 to 4 percent more energy due to the presence of boats.
An activity interrupted even more by boats at Robson Bight is rubbing on pebble beaches. The proportion of an orca's day spent rubbing declines from 17 to 3 percent when boats are around. Most of the boats that disturb killer whales in the area are fishing vessels.
Rob Williams, David Lusseau and Philip S. Hammond. 2006. Estimating relative energetic costs of human disturbance to killer whales (Orcinus orca). Biological Conservation. 133(3): 301-311.