Dear colleagues, My co-authors and I are pleased to share this new article entitled 'Combining hard-part and DNA analyses of scats with biologging and stable isotopes can reveal different diet compositions and feeding strategies within a fur seal population <http://www.int-res.com/abstracts/meps/v584/p1-16/>' published in Marine Ecology Progress Series as a Feature Article. As such it is freely available as Open Source. You can also see the facebook post and tweet from MEPS on this paper: www.facebook.com/MarEcolProgSer https://twitter.com/MEPS_IR/status/938776151585148928
Jeanniard-du-Dot T, Thomas AC, Cherel Y, Trites AW, Guinet C (2017) Combining hard-part and DNA analyses of scats with biologging and stable isotopes can reveal different diet compositions and feeding strategies within a fur seal population. Mar Ecol Prog Ser 584:1-16. https://doi.org/10.3354/meps12381 ABSTRACT: Accurately estimating predators’ diets at relevant spatial and temporal scales is key to understanding animals’ energetics and fitness, particularly in populations whose decline might be related to their diet such as northern fur seals *Callorhinus ursinus*. Our goals were to improve the accuracy of diet estimates and extend understanding of feeding ecology by combining 2 scat-based methods of diet determination (hard-part identification and DNA-metabarcoding) with stable isotope measurements and individual behavioural data. We collected 98 scats on a northern fur seal breeding colony. We also tracked 20 females with biologgers, and took blood samples to determine δ13C and δ15N values as proxies for seal foraging habitat and diet. Results show that diet composition from hard-parts analysis corresponded well with DNA results, with DNA yielding a greater diversity of prey species at a finer taxonomic level. Overall, scat-based methods showed that seals mostly fed on neritic shelf-associated prey. Cluster analyses of combined hard-parts and DNA results however identified 2 diet groups, one mostly neritic and the other mostly pelagic. Stable isotopes and behavioural data revealed that 40% of seals fed in oceanic waters on pelagic prey. This is more than indicated by scat-based analyses, which are likely biased towards animals foraging closest to the colony and underestimate some dietary specializations within the population. Consequently, the combination of multiple methods for diet identification with at-sea tracking of individuals can help identify and quantify specialist groups within a population and provide a wider spatial and temporal ecological context for dietary analysis. Best regards, -- Tiphaine Jeanniard-du-Dot, PhD Fisheries and Oceans Canada/Marine mammal biology and conservation Institut Maurice-Lamontagne 850 Route de la Mer, P.O. Box 1000 Mont-Joli, QC, G5H 3Z4, CANADA Cell:+1-604-724-4230 / Fax: +1-418-775-0740
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