Behavioural responses of killer whales ( Orcinus orca) to whale‐watching boats: opportunistic observations and experimental approaches
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...
Published in: | Journal of Zoology |
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Online Access: | http://dx.doi.org/10.1017/s0952836902000298 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1017%2FS0952836902000298 https://onlinelibrary.wiley.com/doi/pdf/10.1017/S0952836902000298 https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1017/S0952836902000298 |
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crwiley:10.1017/s0952836902000298 2024-06-23T07:55:58+00:00 Behavioural responses of killer whales ( Orcinus orca) to whale‐watching boats: opportunistic observations and experimental approaches Williams, Rob Trites, Andrew W. Bain, David E. 2002 http://dx.doi.org/10.1017/s0952836902000298 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1017%2FS0952836902000298 https://onlinelibrary.wiley.com/doi/pdf/10.1017/S0952836902000298 https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1017/S0952836902000298 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Journal of Zoology volume 256, issue 2, page 255-270 ISSN 0952-8369 1469-7998 journal-article 2002 crwiley https://doi.org/10.1017/s0952836902000298 2024-06-06T04:22:44Z 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 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 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 whale‐watching 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. Article in Journal/Newspaper Orca Orcinus orca Wiley Online Library Journal of Zoology 256 2 255 270 |
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Wiley Online Library |
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crwiley |
language |
English |
description |
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 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 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 whale‐watching 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. |
format |
Article in Journal/Newspaper |
author |
Williams, Rob Trites, Andrew W. Bain, David E. |
spellingShingle |
Williams, Rob Trites, Andrew W. Bain, David E. Behavioural responses of killer whales ( Orcinus orca) to whale‐watching boats: opportunistic observations and experimental approaches |
author_facet |
Williams, Rob Trites, Andrew W. Bain, David E. |
author_sort |
Williams, Rob |
title |
Behavioural responses of killer whales ( Orcinus orca) to whale‐watching boats: opportunistic observations and experimental approaches |
title_short |
Behavioural responses of killer whales ( Orcinus orca) to whale‐watching boats: opportunistic observations and experimental approaches |
title_full |
Behavioural responses of killer whales ( Orcinus orca) to whale‐watching boats: opportunistic observations and experimental approaches |
title_fullStr |
Behavioural responses of killer whales ( Orcinus orca) to whale‐watching boats: opportunistic observations and experimental approaches |
title_full_unstemmed |
Behavioural responses of killer whales ( Orcinus orca) to whale‐watching boats: opportunistic observations and experimental approaches |
title_sort |
behavioural responses of killer whales ( orcinus orca) to whale‐watching boats: opportunistic observations and experimental approaches |
publisher |
Wiley |
publishDate |
2002 |
url |
http://dx.doi.org/10.1017/s0952836902000298 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1017%2FS0952836902000298 https://onlinelibrary.wiley.com/doi/pdf/10.1017/S0952836902000298 https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1017/S0952836902000298 |
genre |
Orca Orcinus orca |
genre_facet |
Orca Orcinus orca |
op_source |
Journal of Zoology volume 256, issue 2, page 255-270 ISSN 0952-8369 1469-7998 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1017/s0952836902000298 |
container_title |
Journal of Zoology |
container_volume |
256 |
container_issue |
2 |
container_start_page |
255 |
op_container_end_page |
270 |
_version_ |
1802648788812169216 |