LÉVY FLIGHTS AND THE SEARCH BEHAVIOUR OF MARINE PREDATORS
It has been hypothesised that animals have evolved to exploit optimal Lévy flights for searching for sparse prey. However, there is some controversy as to whether biological Lévy flights have been reliably detected in empirical data. Since 2006 we have been investigating the search problem in marine predators and have assembled the largest movement dataset for this purpose (12 million move steps and counting…). Predators such as sharks, tunas and penguins present themselves as excellent models to test these ideas because they are large enough to carry electronic devices without impacting normal behaviours, they have an incomplete knowledge of where prey is located, sensory distances are reduced to local scales in the seawater medium, and prey fields in the ocean are sparse and distributed unpredictably.
We have shown that complex patterns of movement during diving behaviour can be readily interpreted using statistical methods. A study of the macroscopic properties of fine-scale vertical movements of seven species of marine vertebrate [basking shark (Cetorhinus maximus), small spotted catshark (Scyliorhinus canicula), bigeye tuna (Thunnus obesus), Atlantic cod, leatherback turtle (Dermochelys coriacea), Magellanic penguin (Spheniscus magellanicus) and southern elephant seal (Mirounga leonina)] revealed Lévy-like scaling laws of search behaviour (Nature, Feb 2008). The emergent properties of animal movement were related to intrinsic patterns of prey abundance with simulations indicating an advantage of undertaking such movements in complex natural prey fields. Research is progressing with analysis of data from 14 species of pelagic fish to test the robustness of these general predictions.
The Team continues to grow…
Professor David Sims (MBA Fellow), Nick Humphries, Jenny Dyer, Nuno Queiroz (also at CIBIO, Portugal), Nick Pade, Dr Emily Southall, Dr Viki Wearmouth (MBA), Emily Shepard, Professors Graeme Hays and Rory Wilson (Swansea University), Dr Corey Bradshaw (University of Adelaide, Australia), Drs Julian Metcalfe and David Righton (CEFAS Laboratory, Lowestoft), Dr Jon Pitchford (University of York), Dr Alex James (University of Canterbury, New Zealand), Dr David Morritt (University of London), Professor Mark Hindell (University of Tasmania), Dr Mike Musyl (University of Hawaii, USA), Dr Mohammed Zaki Ahmed (University of Plymouth), Dr Andrew Brierley (St Andrews University), Drs Kurt Schaefer and Daniel Fuller (Inter-American Tropical tuna Commission, La Jolla, USA), Dr Tom Doyle (University College Cork, Ireland), Dr Jon Houghton (Queen’s University Belfast), Drs Les Noble and Cathy Jones (University of Aberdeen), Dr Juerg Brunnschweiler (ETH Zurich, Switzerland).
Funding: yes, lots… |
