31 research outputs found
Major ethnic group differences in breast cancer screening uptake in Scotland are not extinguished by adjustment for indices of geographical residence, area deprivation, long-term illness and education
Copyright 2012 Elsevier B.V., All rights reserved.Peer reviewedPublisher PD
Ranging patterns of bottlenose dolphins living in oceanic waters : implications for population structure
Author Posting. © The Author(s), 2008. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Marine Biology 156 (2008): 179-192, doi: 10.1007/s00227-008-1075-z.Very little is known about the ecology of
common bottlenose dolphins (Tursiops truncatus) living in
oceanic waters. This study investigated the ranging and
residence pattern, of bottlenose dolphins occurring in the
Azores (Portugal), the most isolated archipelago in the
North Atlantic. Data were collected during standardized
boat-based surveys conducted over a 6-year period in an
area of approximately 5,400 km2 (main study area). To
investigate the extent of movements of individual animals.
non-systematic surveys were also conducted outside this
area. Only 44 individuals out of 966 identified were frequently
sighted within and between years. The remaining
individuals were either temporary migrants from within or
outside the archipelago, or transients. Resident dolphins
showed strong geographic fidelity to the area. Long-distance
movements (of almost 300 km), consistent with
foraging or exploratory trips. were observed among non-resident
dolphins. Home range size was estimated for 31
individuals sighted ≥ 10 times. Range areas of these dolphins
varied in size and location, but considerable overlap
was observed in the areas used, suggesting the absence of
habitat partitioning between resident and non-resident dolphins.
Estimates of home range size of bottlenose dolphins
in the Azores were found to be considerably larger than
those previously reported for this species. It is hypothesized
that dolphins living in the Azores carry out extensive movements
and have large home ranges in response to the lower
density and patchy distribution of prey compared to other
areas. The extensive ranging behaviour and the lack of territoriality
provide an opportunity for interbreeding between
dolphins associated with different islands, thus preventing
genetic differentiation within the population of the Azores.This researd was funded by the Portuguese Science
and Technology Foundation (FCT). under the CETAMARH project
(POCTI/BSF/38991/01 ), by an EU-LlFE program (B4-3200/98/
509), and by an Interreg program (Interreg IIIBMAC/4.2/A2). We are
also grateful to FCT for funding M. A. S. doctoral grant (SFRH/BD/
8609/2002) and post-doctoral grams (SFRH/BPD/29841/2006), and S.
M. M. and M. I. S. research grams through the CETAMARH projec