Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2009. 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 European Journal of Wildlife Research 56 (2010): 151-158, doi:10.1007/s10344-009-0299-7.
Description:
Biological samples of free-ranging dolphins are increasingly used to gain information on
population structure and ecology. In small cetaceans, the gender of individuals usually cannot
be determined at sea, and population sex ratio has to be inferred indirectly. We used
molecular sexing to determine the gender of 340 biopsy samples of bottlenose dolphins,
Tursiops truncatus, spotted dolphins, Stenella frontalis, and common dolphins, Delphinus
delphis, collected around the Azores and Madeira. Sex ratio was globally skewed in favor of
males, and differed between species and archipelagos. Skew was probably influenced by the
selectivity of biopsy collectors and seasonal or year-round predominance of males in natural
populations. Skew was also influenced by sampling duration and intensity. In the Azores,
when several samples were successively collected within the same group, the proportion of
female samples decreased as a function of sample order. This trend indicated a tendency for
females to increasingly avoid the boat while samples were being collected. It showed that
males and females reacted differently to the perturbation caused by the biopsy sampling
process (i.e. sample collection and driving style).
Description:
Portuguese Foundation for
Science and Technology (FCT) and the FEDER program for funding the CETAMARH
(POCTI/BSE/38991/01) and the GOLFINICHO (POCI/BIA-BDE/61009/2004) projects,
S.Q.'s post-doctoral grants (IMAR/FCT- PDOC-006/2001-MoleGen and
SFRH/BPD/19680/2004), M.A.S.'s doctoral (SFRH/BD/8609/2002) and post-doctoral
(SFRH/BPD/29841/2006) grants, S.M.'s investigation assistant grant
(CETAMARHII/POCTI/BSE/38991/2001) and I.C.'s investigation assistant grants
(IMAR/FCT/GOLFINICHO/001/2005 and IMAR/FCT/GOLFINICHO/004/2006). FCT for its pluri-annual funding to Research Unit #531 and the EU funded
program Interreg IIIb for funding the MACETUS project (MAC/4.2/M10) as well as R.P. and S.M.’s grants (IMAR/INTERREGIIIb/MACETUS/MAC1/2).
Keywords:
Bottlenose dolphin
;
Common dolphin
;
Spotted dolphin
;
Biological samples
;
Sex ratio
;
NE Atlantic
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
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