Whitehead Hal

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Whitehead
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Hal
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  • Preprint
    Changes in persistent contaminant concentration and CYP1A1 protein expression in biopsy samples from northern bottlenose whales, Hyperoodon ampullatus, following the onset of nearby oil and gas development
    ( 2007-05-09) Hooker, Sascha K. ; Metcalfe, Tracy L. ; Metcalfe, Chris D. ; Angell, Carolyn M. ; Wilson, Joanna Y. ; Moore, Michael J. ; Whitehead, Hal
    A small population of endangered northern bottlenose whales (Hyperoodon ampullatus) inhabits “The Gully” Marine Protected Area on the Scotian Shelf, eastern Canada. Amid concerns regarding nearby oil and gas development, we took 36 skin and blubber biopsy samples in 1996-97 (prior to major development) and 2002-03 (five years after development began), and 3 samples from a population in the Davis Strait, Labrador in 2003. These were analysed for cytochrome P4501A1 (CYP1A1) protein expression (n=36), and for persistent contaminants (n=23). CYP1A1 showed generally low expression in whales from The Gully, but higher levels during 2003, potentially co-incident with recorded oil spills, and higher levels in Davis Strait whales. A range of PCB congeners and organochlorine compounds were detected, with concentrations similar to other North Atlantic odontocetes. Concentrations were higher in whales from The Gully than from the Davis Strait, with significant increases in 4,4’-DDE and trans-nonachlor in 2002-03 relative to 1996-97.
  • Article
    Impact assessment research : use and misuse of habituation, sensitisation and tolerance in describing wildlife responses to anthropogenic stimuli
    (Inter-Research, 2009-12-03) Bejder, Lars ; Samuels, Amy ; Whitehead, Hal ; Finn, H. ; Allen, S.
    Studies on the effects of anthropogenic activity on wildlife aim to provide a sound scientific basis for management. However, misinterpretation of the theoretical basis for these studies can jeopardise this objective and lead to management outcomes that are detrimental to the wildlife they are intended to protect. Misapplication of the terms ‘habituation’, ‘sensitisation’ and ‘tolerance’ in impact studies, for example, can lead to fundamental misinterpretations of research findings. Habituation is often used incorrectly to refer to any form of moderation in wildlife response to human disturbance, rather than to describe a progressive reduction in response to stimuli that are perceived as neither aversive nor beneficial. This misinterpretation, when coupled with the widely held assumption that habituation has a positive or neutral outcome for animals, can lead to inappropriate decisions about the threats human interactions pose to wildlife. We review the conceptual framework for the use of habituation, sensitisation and tolerance, and provide a set of principles for their appropriate application in studies of behavioural responses to anthropogenic stimuli. We describe how cases of presumed habituation or sensitisation may actually represent differences in the tolerance levels of wildlife to anthropogenic activity. This distinction is vital because impact studies must address (1) the various mechanisms by which differing tolerance levels can occur; and (2) the range of explanations for habituation- and sensitisation-type responses. We show that only one mechanism leads to true behavioural habituation (or sensitisation), while a range of mechanisms can lead to changes in tolerance.