Behavioural responses of killer whales to whale-watching : opportunistic observations and experimental approaches ...

• Main Author: Williams, Robert Michael
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Orca; Orcinus orca
• Online Access: https://dx.doi.org/10.14288/1.0074829; https://doi.library.ubc.ca/10.14288/1.0074829

Johnstone Strait provides important summer habitat for British Columbia's northern resident killer whales (Orcinus orca). The site is also an active whale-watching area. A voluntary code of conduct recommends that boaters do not approach whales closer than 100 m to address perceived, rather than demonstrated, effects of boat traffic on killer whales. The purpose of my study was to test the relevance of this guideline. Relationships between boat traffic and whale behaviour were studied in 1995 and 1996 by shore-based theodolite tracking of 25 identifiable focal animals from the population of 209 whales. Individual killer whales were repeatedly tracked in the absence of boats and during approaches by a 5.2 m motorboat that paralleled each whale at 100 m. In addition, whales were tracked opportunistically, when no effort was made to manipulate boat traffic. Dive times, swim speeds, and surface active behaviours such as breaching and spyhopping were recorded. Male killer whales swam significantly faster than ...