Dr Andrew Trites
Behavioural responses of killer whales to whale-watching: opportunistic observations and experimental approaches.
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 females. Whales responded to experimental approaches by adopting a less predictable path than observed during the preceding, no-boat period, although males and females employed 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 suggests 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 experimental studies when assessing behavioural impacts of human activity on killer whales.
Behavioural responses of killer whales to whale-watching: opportunistic observations and experimental approaches. Williams, R.M. 1999. MSc thesis, University of British Columbia, Vancouver BC. 68 pages (PDF)
Behavioral responses of male killer whales to a ‘leapfrogging’ vessel. Williams, R.M., D.E. Bain, J.K.B. Ford and A.W. Trites. 2002. Journal of Cetacean Research 4:305-310. (PDF)
Behavioural responses of killer whales (Ornicus orca) to whale-watching: opportunistic observations and experimental approaches. Williams, R.M., A.W. Trites and D.E. Bain. 2002. Journal of Zoology, London. 256:255-270. (PDF)
Effect of ration size and meal frequency on assimilation and digestive efficiency in yearling Steller sea lions, Eumetopias jubatus. Rosen, D.A.S., L. Williams and A.W. Trites. 2000. (PDF)
Articles published or accepted in refereed journals;
Erin Ashe, Dawn Noren and Rob Williams. 2010. Animal behaviour and marine protected areas: incorporating behavioural data into the selection of marine protected areas for an endangered killer whale population. Animal Conservation 13:196-203. (PDF)
Rob Williams and Patrick O’Hara. 2010. Modelling ship strike risk to fin, humpback and killer whales in British Columbia, Canada. Journal of Cetacean Research and Management 11:1-8 (PDF)
Rob Williams, Tom Okey, Scott Wallace and Vince Gallucci VF (2010) Shark aggregation in coastal waters of British Columbia. Marine Ecology Progress Series 414:249-256 (PDF)
Rob Williams and Len Thomas. Cost-effective abundance estimation of rare animals: Testing performance of small-boat surveys for killer whales in British Columbia. Biological Conservation 142:1542-1547. (PDF)
Rob Williams and Dawn Noren. (2009) Swimming speed, respiration rate and estimated cost of transport in killer whales. Marine Mammal Science 25:327-350. (PDF)
Rob Williams, David Lusseau and Phil Hammond. (2009) The role of social aggregations and protected areas in killer whale conservation: the mixed blessing of critical habitat. Biological Conservation 142:709-719.
Rob Williams*, David Bain, David Lusseau and Jodi Smith. (2009) Effects of vessel traffic on behaviour patterns of individual southern resident killer whales (Orcinus orca). Endangered Species Research 6:199-209. (* – Joint first-authorship.)
David Lusseau, David Bain, Rob Williams and Jodi Smith. (2009) Vessel traffic disrupts foraging behaviour of southern resident killer whales. Endangered Species Research 6:211-221.
Rob Williams, Anna Hall and Arliss Winship. (2008) Potential limits to anthropogenic mortality of small cetaceans in coastal waters of British Columbia. Canadian Journal of Fisheries and Aquatic Sciences 65(9):1867-1878.
Rob Williams and Len Thomas. (2007) Distribution and abundance of marine mammals in the coastal waters of BC, Canada. Journal of Cetacean Research and Management 9(1): 15-28.
Len Thomas, Rob Williams and Doug Sandilands. (2007) Designing line transect surveys for complex survey regions.Journal of Cetacean Research and Management 9(1): 1-13.
Williams, R., Leaper, R., Zerbini, A. and Hammond, P.S. (2007) Methods for investigating measurement error in cetacean line transect surveys. Journal of the Marine Biological Association of the United Kingdom 87: 313-320.
Rob Williams and Erin Ashe. (2007) Killer whale evasive tactics vary with boat number. Journal of Zoology (London) 272(4): 390-397.
Rob Williams and Kim Crosbie. (2007) Antarctic whales and Antarctic tourism. Tourism in Marine Environments (Special Issue on Polar Tourism).
Rob Williams and David Lusseau. (2006) A killer whale social network is vulnerable to targeted removals. Biology Letters 2(4): 497-500.
Rob Williams, Sharon Hedley and Phil Hammond. (2006) Modelling distribution and abundance of Antarctic baleen whales using ships of opportunity. Ecology and Society 11(1). http://ecologyandsociety.org/vol11/iss1/art1/
Rob Williams, David Lusseau and Phil Hammond. (2006) Estimating relative energetic costs of human disturbance to killer whales (Orcinus orca). Biological Conservation 133(3): 301-311.
Alexandra Morton and Rob Williams. (2006) Response of Sea Lice infestation on wild Pink and Chum Salmon smolts to arrival of parasitized wild adult salmon. Canadian Field-Naturalist 120(2): 199-204. [ABSTRACT: PDF]
Alexandra Morton, Rick Routledge and Rob Williams. (2005) Temporal patterns of sea louse infestation on wild Pacific salmon in relation to the fallowing of Atlantic salmon farms. North American Journal of Fisheries Management 25: 811-821. [PDF]
David Lusseau, Rob Williams, Ben Wilson, Kate Grellier, Tim Barton, Phil Hammond and Paul Thompson. (2004) Parallel influence of climate on the behaviour of Pacific killer whales and Atlantic bottlenose dolphins. Ecology Letters 7: 1068-1076. [PDF]
Meike Scheidat, Cristina Castro, Janira Gonzalez and Rob Williams. (2004) Behavioural responses of humpback whales to whalewatching boats near Isla de la Plata, Machalilla National Park, Ecuador. Journal of Cetacean Research and Management 6(1): 63-68. [PDF]
Alexandra Morton and Rob Williams. (2003). First report of the sea louse, Lepeophtheirus salmonis, infestation on juvenile Pink Salmon, Oncorhynchus gorbuscha, in nearshore habitat. Canadian Field-Naturalist 117: 634-641. [ABSTRACT: morton_williams_2003_CFN.txt]
Rob Williams, David Bain, John Ford and Andrew Trites. (2002) Behavioural responses of male killer whales to a ‘leapfrogging’ vessel. Journal of Cetacean Research and Management 4(3): 305-310. [PDF]
Rob Williams, Andrew Trites and David Bain. (2002) Behavioural responses of killer whales to whale-watching traffic: opportunistic observations and experimental approaches. Journal of Zoology (London) 256: 255-270. [PDF]
Papers in press;
- Other refereed contributions;
Rob Williams and Greg Donovan. Blue whales. In: Riffenburgh, B. (ed.) Encyclopedia of the Antarctic, Routledge, New York, 1248 pp.
Rob Williams and Greg Donovan. Fin whales. In: Riffenburgh, B. (ed.) Encyclopedia of the Antarctic, Routledge, New York, 1248 pp.
Rob Williams and Greg Donovan. Sei whales. In: Riffenburgh, B. (ed.) Encyclopedia of the Antarctic, Routledge, New York, 1248 pp.