We are pleased to announce a recent publication in Ecology Letters which may be of interest to anyone tracking animals and interested in the routes they follow. We compare the actual routes of individuals GPS tracked by satellite, to the optimum routes to minimise travel times.
Hays GC, Christensen A, Fossette S, Schofield G, Talbot J, Mariani P. (2014). Route optimisation and solving Zermelo's navigation problem during long distance migration in cross flows. Ecology Letters 17, 137-143. doi: 10.1111/ele.12219 Abstract: The optimum path to follow when subjected to cross flows was first considered over 80 years ago by the German mathematician Ernst Zermelo, in the context of a boat being displaced by ocean currents, and has become known as the 'Zermelo navigation problem'. However, the ability of migrating animals to solve this problem has received limited consideration, even though wind and ocean currents cause the lateral displacement of flyers and swimmers, respectively, particularly during long-distance journeys of 1000s of kilometres. Here, we examine this problem by combining long-distance, open-ocean marine turtle movements (obtained via long-term GPS tracking of sea turtles moving 1000s of km), with a high resolution basin-wide physical ocean model to estimate ocean currents. We provide a robust mathematical framework to demonstrate that, while turtles eventually arrive at their target site, they do not follow the optimum (Zermelo's) route. Even though adult marine turtles regularly complete incredible long-distance migrations, these vertebrates primarily rely on course corrections when entering neritic waters during the final stages of migration. Our work introduces a new perspective in the analysis of wildlife tracking datasets, with different animal groups potentially exhibiting different levels of complexity in goal attainment during migration. The paper is downloadable from the Ecology Letters website: http://onlinelibrary.wiley.com/doi/10.1111/ele.12219/abstract Or for a reprint please contact Graeme Hays: [email protected]<mailto:[email protected]> Cheers, Graeme Professor Graeme Hays School of Life and Environmental Sciences, Deakin University Warrnambool Campus, PO Box 423, Warrnambool, VIC 3280 (+61 3 55633311) http://scholar.google.co.uk/citations?user=7rc3SmAAAAAJ&hl=en&oi=ao Recent highlights: Hays GC, Christensen A, Fossette S, Schofield G, Talbot J, Mariani P. (2014). Route optimisation and solving Zermelo's navigation problem during long distance migration in cross flows. Ecology Letters 17, 137-143. doi: 10.1111/ele/12219 Hinder SL, Gravenor MB, Edwards M, Ostle C, Bodger OG, Lee PLM, Walne AW, Hays GC (2014). Multi-decadal range changes vs thermal adaptation for north east Atlantic oceanic copepods in the face of climate change. Global Change Biology 20, 140-146. doi: 10.1111/gcb.12387 Important Notice: The contents of this email are intended solely for the named addressee and are confidential; any unauthorised use, reproduction or storage of the contents is expressly prohibited. If you have received this email in error, please delete it and any attachments immediately and advise the sender by return email or telephone. Deakin University does not warrant that this email and any attachments are error or virus free.
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