Subject: Abstract: Abstract on bottlenose dolphin habitat use (fwd)

Mike Williamson (
Wed, 11 Feb 1998 14:22:04 -0500 (EST)


---------- Forwarded message ----------
Date: Tue, 10 Feb 1998 14:04:48 +0000
From: Ben Wilson <>
Reply-To: Marine Mammals Research and Conservation Discussion
Subject: Abstract on bottlenose dolphin habitat use

Dear Marmammers,

The following paper has come out in the Journal of Applied Ecology.

Habitat use by bottlenose dolphins: seasonal distribution and stratified
movement patterns in the Moray Firth, Scotland.
Ben Wilson, Paul M. Thompson, & Philip S. Hammond. Journal of Applied
Ecology, 1997, 34, 1365-1374.

   (1) This study investigated the distribution of a population of
bottlenose dolphins (Tursiops truncatus) resident in the Moray Firth off NE
Scotland. Results add to information from studies in tropical areas to
provide a better understanding of area use in this species.
   (2) Boat-based surveys and photo-identification techniques were used to
study the distribution and movements of individually recognisable dolphins
over a three year period.
   (3) Dolphins were seen in all months of the year, but there were
consistent seasonal fluctuations in the number of individuals present.
Numbers were low in winter and spring and peaked in summer and autumn.
   (4) Dolphins were seen throughout the survey area but concentrated in
three regions. Each had similar topographic features being centred on deep,
narrow channels subject to strong tidal flows.
   (5) Area use changed with season. The outer part of the inner Moray
Firth study area was used for most of the year and areas closer to the head
of the firth were used seasonally.
   (6) The summer increase in numbers in the inner Moray Firth was not
simply due to incomers diluting an already resident population. Instead
there was a stratified movement of all individuals. This maintained
geographical stratification suggests that competition between individuals
or social groupings may shape distribution in this population.
   (7) Individuals demonstrated rapid movements across the population's
range. For instance, one individual was sighted at locations 190 Km apart
within a five day period.
   (8) In terms of conservation, the high use of the mouths of the inner
firths warrants special attention. Furthermore, the stratification patterns
amongst dolphins suggest that individuals do not move freely within the
inner Moray Firth and therefore may be unable to move away from localised
disturbance or pollution.

Reprints are available from Ben Wilson, Lighthouse Field Station, Cromarty,
Ross-shire, IV11 8YJ, The UK.