The understanding of the interplay of movement, behaviour and physiology that biologging offers has applied relevance for a range of fields, including evolutionary ecology, wildlife conservation and behavioural ecology. In recognition of this, the Journal of Animal Ecology has an upcoming Special Feature on Biologging (submissions due 20th September).
One of the issues when studying the movements of large animals is the fact that they cover large distances. Here, Dr Ana Sequeira from the University of Western Australia tells us about her collaborative approach to mapping marine megafauna movements.
Ever since I was a child, I have been fascinated with the ocean and the animals that move within it. One of the things that captured my imagination was thinking about the freedom with which large migratory animals move through seawater while covering large distances across the global ocean. My fascination increased when I discovered that not much was known about the whale shark – such an iconic marine megafauna species – and so I set out to make a few discoveries myself by embarking on a PhD to study the global distribution of whale sharks.
Part of the problem in understanding movements of such migratory animals is that the focus of past research has been on isolated areas or work by single groups. But we know that these animals can traverse entire ocean basins, so there is a need to do more encompassing studies and to understand movements at much larger areas. For my first PhD chapter, I compiled all tracking data available for whale sharks at a global scale (Sequeira et al. 2013) but only to find out that not much data were publically available at that time. Unfortunately, this meant that not many inferences could be made from such a sparse dataset. Indeed, part of the original idea for my PhD was to tag whale sharks in different locations of the Indian Ocean to contribute to the pool of tracking datasets available for the species. Although my PhD took a different turn in the end, I still managed to participate in whale shark field trips to Ningaloo Reef, Western Australia, throughout my PhD. Each of these field trips was the most amazing experience of my life. Being in the water with such an enormous, harmless creature is just indescribable. During the time of my PhD, I swam with whale sharks on more than 300 occasions; and each of them felt as intense as the first.
However, the questions: ‘where are these animals going to?’, ‘where have they come from?’, and ‘why are they here?’ kept my curiosity alive. In fact, this is the reason why it is important to understand the movement of marine megafauna species. Without understanding how they move, which areas of the ocean are of importance to them, or the reasons why they occur in specific locations at specific times of the year, our job of conserving these species will be hard, if not impossible. But, as for whale sharks, marine animal tracking studies are often relatively local and restricted to small sample size, and the best way to move forward it to work together in order to improve our understanding of marine megafauna movements.
My current research aims to achieve this by fostering collaborations that collate multi-species tracking datasets for the marine environment, and has already led to some fascinating results. For example, in a recent publication involving almost 60 authors from around the world, we undertook one of the largest multi-species marine tracking studies ever conducted. Our results highlighted a convergence of movement patterns among of marine megafauna species, including sharks, whales, penguins, seals, sea birds, and turtles. In this study we analysed more than 2,500 tracks and found out that unrelated marine species display similar movement patterns when moving in coastal or open oceans (Sequeira et al. 2018). This result highlighted that the movement of marine megafauna differs significantly from the movement of terrestrial species. On land, animal movement patterns are commonly associated with their body size or length. In the marine environment, the movement patterns seem to differ based on habitat, with animals displaying more ‘directed’ movements in the open ocean in comparison with more ‘complex’ movements in coastal waters. It is important to understand how animals adapt their movement patterns to different environments because increasing anthropogenic activities and coastal changes might impact them in ways we do not expect.
This work is one of the many publications that came out of the Marine Megafauna Movement Analytical Program (MMMAP; mmmap.wordpress.com). MMMAP started in 2014, setting out to synthesise existing datasets of marine megafauna movement to address fundamental scientific questions about animal movement and assess how anthropogenic activities might impact these species. Since its inception, MMMAP has produced a number of publications in high-impact journals (Hays et al. 2016, Meekan et al. 2017, Rodriguez et al. 2017, Sequeira et al. 2018, Thums et al. 2018) and plans to continue to do so. Because marine megafauna cover such large extents of the global ocean through their migratory behaviour, big collaborative initiatives such as MMMAP provide the means to move forward our understanding of these species movement behaviour. Currently, our global dataset on tracking data of marine megafauna has expanded immensely, and, together with the rest of the marine animal movement community, we are now looking into questions associated with effects of interactions between marine megafauna and anthropogenic activities.
Hays, G. C., L. C. Ferreira, A. M. M. Sequeira, M. G. Meekan, C. M. Duarte, H. Bailey, F. Bailleul, W. Don Bowen, M. J. Caley, D. P. Costa, V. M. Eguiluz, S. Fossette, A. S. Friedlaender, N. Gales, A. C. Gleiss, J. Gunn, R. Harcourt, E. L. Hazen, M. R. Heithaus, M. Heupel, K. Holland, M. Horning, I. Jonsen, G. L. Kooyman, C. G. Lowe, P. T. Madsen, H. Marsh, R. A. Phillips, D. Righton, Y. Ropert-Coudert, K. Sato, S. A. Shaffer, C. A. Simpfendorfer, D. W. Sims, G. Skomal, A. Takahashi, P. N. Trathan, M. Wikelski, J. N. Womble, and M. Thums. (2016). Key Questions in Marine Megafauna Movement Ecology. Trends in Ecology & Evolution 31: 463-475.
Meekan, M. G., C. M. Duarte, J. Fernandez-Gracia, M. Thums, A. M. Sequeira, R. Harcourt, and V. M. Eguiluz. ()2017. The Ecology of Human Mobility. Trends in Ecology & Evolution 32: 198-210.
Rodriguez, J. P., J. Fernandez-Gracia, M. Thums, M. A. Hindell, A. M. Sequeira, M. G. Meekan, D. P. Costa, C. Guinet, R. G. Harcourt, C. R. McMahon, M. Muelbert, C. M. Duarte, and V. M. Eguiluz. (2017). Big data analyses reveal patterns and drivers of the movements of southern elephant seals. Scientific Reports 7: 112.
Sequeira, A., J. Rodríguez, V. Eguíluz, R. Harcourt, M. Hindell, D. Sims, C. Duarte, D. Costa, J. Fernandez-Gracia, L. Ferreira, G. Hays, M. Heupel, M. Meekan, A. Aven, F. Bailleul, A. Baylis, M. Berumen, C. Braun, J. Burns, M. Caley, R. Campbell, R. Carmichael, E. Clua, L. Einoder, A. Friedlaender, G. ME, S. Goldsworthy, C. Guinet, J. Gunn, D. Hamer, N. Hammerschlag, M. Hammill, L. Hückstädt, N. Humphries, M.-A. Lea, A. Lowther, A. Mackay, E. McHuron, J. McKenzie, L. McLeay, C. McMahon, K. Mengersen, M. Muelbert, A. Pagano, B. Page, N. Queiroz, P. Robinson, S. Shaffer, M. Shivji, G. Skomal, S. Thorrold, S. Villegas-Amtmann, M. Weise, R. Wells, B. Wetherbee, A. Wiebkin, B. Wienecke, and M. Thums. (2018).Convergence of marine megafauna movement patterns in coastal and open oceans. Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1716137115
Sequeira, A. M. M., C. Mellin, M. G. Meekan, D. W. Sims, and C. J. A. Bradshaw. (2013). Inferred global connectivity of whale shark Rhincodon typus populations. Journal of Fish Biology 82: 367-389.
Thums, M., J. Fernández-Gracia, A. M. M. Sequeira, V. M. Eguíluz, C. M. Duarte, and M. G. Meekan. (2018). How big data fast tracked human mobility research and the lessons for animal movement ecology. Frontiers in Marine Science, DOI: 10.3389/fmars.2018.00021