Dear colleagues, My co-authors and I are happy to announce the publication of the following paper in Marine Ecology Progress Series:
Christiansen, F., Vivier, F., Charlton, C., Ward, R., Amerson, A., Burnell, S. & Bejder, L. 2018. Maternal body size and condition determine calf growth rates in southern right whales. Marine Ecology Progress Series 592:267-282. In this study we used unmanned aerial vehicles to repeatedly measure the body size and condition of southern right whale mother and calf pairs through an entire breeding season in South Australia. Apart from the biological findings, the methodology used in this paper should be of interest to anyone interested in UAV photogrammetry work. The paper and supplementary materials detail the many aspects that need to be considered when doing UAV photogrammetry work on whales, including data filtering based on picture grading, error estimations, identifying minimum sample size and duration for estimating growth, and how to account for errors in sensitivity analyses etc.. Please find the abstract and a link to the paper below: Abstract: The cost of reproduction is a key parameter determining a species’ life history strategy. Despite exhibiting some of the fastest offspring growth rates among mammals, the cost of reproduction in baleen whales is largely unknown since standard field metabolic techniques cannot be applied. We quantified the cost of reproduction for southern right whales Eubalaena australis over a 3 mo breeding season. We did this by determining the relationship between calf growth rate and maternal rate of loss in energy reserves, using repeated measurements of body volume obtained from unmanned aerial vehicle photogrammetry. We recorded 1118 body volume estimates from 40 female and calf pairs over 40 to 89 d. Calves grew at a rate of 3.2 cm d−1 (SD = 0.45) in body length and 0.081 m3 d−1 (SD = 0.011) in body volume, while females decreased in volume at a rate of 0.126 m3 d−1 (SD = 0.036). The average volume conversion efficiency from female to calf was 68% (SD = 16.91). Calf growth rate was positively related to the rate of loss in maternal body volume, suggesting that maternal volume loss is proportional to the energy investment into her calf. Maternal investment was determined by her body size and condition, with longer and more rotund females investing more volume into their calves compared to shorter and leaner females. Lactating females lost on average 25%of their initial body volume over the 3 mo breeding season. This study demonstrates the considerable energetic cost that females face during the lactation period, and highlights the importance of sufficient maternal energy reserves for reproduction in this capital breeding species. The paper can be accessed from the following link: http://www.int-res.com/abstracts/meps/v592/p267-281/ Best regards, Fredrik Christiansen Postdoctoral Research Fellow Cetacean Research Unit, School of Veterinary and Life Sciences Murdoch University, Murdoch, WA 6150, Australia +61 417 502 098, f.christian...@murdoch.edu.au<mailto:f.christian...@murdoch.edu.au>, twitter: @FChristiansen83 http://scholar.google.com.au/citations?user=vkA5Y3EAAAAJ&hl=en&oi=sra http://www.researchgate.net/profile/Fredrik_Christiansen3/?ev=hdr_xprf
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