I would like draw your attention to our new publication. The abstract is
given below & the pdf is attached. Hope you find it informative.
I will be attending the Marine Mammal Conference next week in San Diego,
so if anyone has any comments, please don't hesitate to ask.
Response of travelling bottlenose dolphins (Tursiops aduncus) to
experimental approaches by a powerboat in Jervis Bay, New South Wales,
Michelle Lemon*, Tim P. Lynch, Douglas H. Cato, and Robert G.
* Corresponding author.
Email address: (M. Lemon)
Powerboats are potentially a significant source of disturbance to
coastal cetaceans. Information is scarce, however, on the nature of
interactions between powerboats and dolphins, particularly when both
surface and acoustic behaviour are combined. The surface behaviour and
acoustic response of travelling dolphins to approaches by a powerboat
were assessed by a series of experimental trials between November 2001
and November 2003 in Jervis Bay, New South Wales, Australia. Dolphin
behaviour was monitored continuously from an independent research boat
before, during and after a powerboat approached (n=12). Treatments were
interspersed with control observations (n=12). Changes in surface
behaviour indicated differences between the treatment and control
periods (z = 2.24, p = 0.025), with dolphins tending to alter their
surface behaviour when exposed to the powerboat approach. Analysis also
revealed a change in the direction of travel by dolphin groups when
approached (z = 3.22, p = 0.001). Changes in surface behaviour occurred
at vessel approach distances outside the minimum approach distance of 30
metres for recreational and commercial vessels, as proposed by the New
South Wales National Parks and Wildlife Service. In contrast, there
were no changes in dolphin whistle rates (F3,12 = 0.74, p = 0.54) or the
duration of echolocation click bouts (F3,12 = 0.76, p = 0.59) when
approached. These findings indicate that powerboats do affect the
surface behaviour and direction of travelling inshore bottlenose
dolphins in Jervis Bay; however it appears that this impact is not
reflected in their acoustic behaviour.
Michelle Lemon B.Sc.(Hons.)
Marine Mammal Research Group
Graduate School of the Environment
Macquarie University, Sydney, Australia, 2109
Don't let today's disappointments
cast a shadow on tomorrow's dreams.