Dear colleagues, We are pleased to announce the recent publication of the following note on pilot whale dorsal fin shape:
Augusto, Joana F.; Frasier, Timothy R.; Whitehead, Hal. (2013). Using photography to determine sex in pilot whales (*Globicephala melas*) is not possible: Males and females have similar dorsal fins. Marine Mammal Science 29(1): 213-220. doi: 10.1111/j.1748-7692.2011.00546.x Summary: Pilot whales are sexually dimorphic odontocetes. Males are larger than females and, since dorsal fins growth isometrically with body size, also possess larger dorsal fins. Males are also thought to have dorsal fins that are thicker at the edge, with more rounded contour and rounded edge. The population of long finned pilot whales that summers in the waters around Cape Breton, Canada, has been studied since 1998. There are currently more than 2000 individuals photo- identified. If these individuals could be assigned to sex, the data set would be much more powerful .We tested whether dorsal fin shape, number of mark points and saddle patch density are different enough between sexes so they could be used to predict sex based on photographic data. We biopsied 18 known individuals from the population and determined their sex genetically, through PCR of the Zfx and Zfy introns. We used Eliptical Fourier Descriptor Analysis to determine the most variable parts of the dorsal fin shape for those individuals, and examined whether the patterns differed according to sex using a discriminant function analysis and MANOVA. Saddle patch density was compared across sexes using a permutation test, and the number of mark points using a Mann-Whitney U test. Eleven of the sampled individuals were males and seven females. We found that males and females have similar dorsal fin shape (MANOVA P=0.119), saddle patch density (P=0.17) and mark point distribution (P=0.23). It does not seem to be possible to use either dorsal fin shape, saddle patch density or number of mark points to usefully predict sex of individual pilot whales. It is available at http://onlinelibrary.wiley.com/doi/10.1111/j.1748-7692.2011.00546.x/abstractor by request. Cheers, Joana Augusto ******************************* Joana Augusto, M.Sc. PhD candidate Whitehead Lab Biology Dept. Dalhousie University Halifax, NS B3H 4R2 Canada http://whitelab.biology.dal.ca/ Let's Talk Science Coordinator Dalhousie University [email protected] http://letstalkscience.ca/dalhousie
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