Whale-watching activity in Bahia Malaga, on the Pacific coast of Colombia, and its effect on humpback whale (Megaptera novaeangliae) behavior

During the whale-watching season of 2008, 6,663 whale watchers and 267 boat trips were recorded in Bahía Málaga, Colombia. Forty-four percent of humpback whale pods sighted in the area were approached by boats. Operators in 2008 did not comply with Colombian whale-watching guidelines during most encounters. The modal distance between whales and boats was 50 m. Ninety-four percent of boats approached too fast (>3 knots), and 78.6% of them approached mother–calf pods. On average, a pod of whales was observed for 42.6 minutes (SD 33.1), and by more than one boat in 60.2% of cases. As a consequence of boats' presence, whales modified their behavior by reducing blows per minute, moved faster and more erratically, increased breaching frequency, and decreased resting behavior.