Sex bias in biopsy samples collected from free-ranging dolphins
Silva, Monica A.
Matos, Jose A.
Santos, Ricardo S.
MetadataShow full item record
KeywordBottlenose dolphin; Common dolphin; Spotted dolphin; Biological samples; Sex ratio; NE Atlantic
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).
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.
Showing items related by title, author, creator and subject.
Organohalogen contaminants and metabolites in cerebrospinal fluid and cerebellum gray matter in short-beaked common dolphins and Atlantic white-sided dolphins from the western North Atlantic Montie, Eric W.; Reddy, Christopher M.; Gebbink, Wouter A.; Touhey, Kathleen M.; Hahn, Mark E.; Letcher, Robert J. (2009-03-12)Concentrations of several congeners and classes of organohalogen contaminants (OHCs) and/or their metabolites, namely organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), hydroxylated-PCBs (OH-PCBs), ...
Cruz, Maria João; Menezes, Gui; Machete, Miguel; Silva, Monica A. (Public Library of Science, 2016-11-16)Common dolphins (Delphinus delphis) are responsible for the large majority of interactions with the pole-and-line tuna fishery in the Azores but the underlying drivers remain poorly understood. In this study we investigate ...
Mooney, T. Aran; Nachtigall, Paul E.; Vlachos, Stephanie (2009-03-10)There is increasing concern that human-produced ocean noise is adversely affecting marine mammals, as several recent cetacean mass strandings may have been caused by animals’ interactions with naval “mid-frequency” sonar. ...