Another item people can follow up if interested. I suspect the some of the
impacts reported in this item would apply to other forms of ecotourism.
The following document is accessible at
http://faculty.washington.edu/dbain/jsww.pdf
J. Zool., Lond. (2002) 256, 255±270 # 2002 The Zoological Society of London
Printed in the United Kingdom
Behavioural responses of killer whales (Orcinus orca) to whale-watching boats:
opportunistic observations and experimental approaches
Rob Williams1*, Andrew W. Trites1 and David E. Bain2
1 Department of Zoology and Marine Mammal Research Unit, Fisheries Centre,
University of British Columbia, 6248 Biological Sciences Road, Vancouver, BC V6T
1Z4, Canada
2 D. E. Bain, Six Flags Marine World Vallejo, Vallejo, CA 94589, USA. E-mail:
(Accepted 5 March 2001)
Abstract
Johnstone Strait provides important summer habitat for the northern resident
killer whales Orcinus orca of British Columbia. The site is also an active
whale-watching area. A voluntary code of conduct requests that boats do not
approach whales closer than 100 m to address perceived, rather than
demonstrated, effects of boat traffic on killer whales. The purpose of the study
was to test the relevance of this distance guideline. Relationships between boat
traffic and whale behaviour were studied in 1995 and 1996 by shorebased
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 spy-hopping were recorded. On average, male killer whales
swam significantly faster than females. Whales responded to experimental
approaches by adopting a less predictable path than observed during the
preceding, no-boat period, although males and females used subtly different
avoidance tactics. Females responded by swimming faster and increasing the angle
between successive dives, whereas males maintained their speed and chose a
smooth, but less direct, path. Canonical correlations between whale behaviour
and vessel proximity are consistent with these conclusions, which suggest that
weakening whalewatching guidelines, or not enforcing them, would result in
higher levels of disturbance. High variability in whale behaviour underscores
the importance of large sample size and extensive experimentation when assessing
the impacts of human activity on killer whales.
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