Scaling laws of marine predator search behaviour

TY - JOUR

T1 - Scaling laws of marine predator search behaviour

AU - Sims, David W.

AU - Southall, Emily J.

AU - Humphries, Nicolas E.

AU - Hays, Graeme C.

AU - Bradshaw, Corey J. A.

AU - Pitchford, Jon

AU - James, Alex

AU - Ahmed, Mohammed Z.

AU - Brierley, Andrew S.

AU - Hindell, Mark A.

AU - Morritt, David

AU - Musyl, Michael K.

AU - Righton, David

AU - Shepard, Emily L. C.

AU - Wearmouth, Victoria J.

AU - Wilson, Rory P.

AU - Witt, Matthew J.

AU - Metcalfe, Julian D.

PY - 2008/2/28

Y1 - 2008/2/28

N2 - Many free- ranging predators have to make foraging decisions with little, if any, knowledge of present resource distribution and availability(1). The optimal search strategy they should use to maximize encounter rates with prey in heterogeneous natural environments remains a largely unresolved issue in ecology(1-3). Levy walks(4) are specialized random walks giving rise to fractal movement trajectories that may represent an optimal solution for searching complex landscapes(5). However, the adaptive significance of this putative strategy in response to natural prey distributions remains untested(6,7). Here we analyse over a million movement displacements recorded from animal- attached electronic tags to show that diverse marine predators - sharks, bony fishes, sea turtles and penguins - exhibit Levy- walk- like behaviour close to a theoretical optimum(2). Prey density distributions also display Levy- like fractal patterns, suggesting response movements by predators to prey distributions. Simulations show that predators have higher encounter rates when adopting Levy- type foraging in natural- like prey fields compared with purely random landscapes. This is consistent with the hypothesis that observed search patterns are adapted to observed statistical patterns of the landscape. This may explain why Levy- like behaviour seems to be widespread among diverse organisms(3), from microbes(8) to humans(9), as a `rule' that evolved in response to patchy resource distributions.

AB - Many free- ranging predators have to make foraging decisions with little, if any, knowledge of present resource distribution and availability(1). The optimal search strategy they should use to maximize encounter rates with prey in heterogeneous natural environments remains a largely unresolved issue in ecology(1-3). Levy walks(4) are specialized random walks giving rise to fractal movement trajectories that may represent an optimal solution for searching complex landscapes(5). However, the adaptive significance of this putative strategy in response to natural prey distributions remains untested(6,7). Here we analyse over a million movement displacements recorded from animal- attached electronic tags to show that diverse marine predators - sharks, bony fishes, sea turtles and penguins - exhibit Levy- walk- like behaviour close to a theoretical optimum(2). Prey density distributions also display Levy- like fractal patterns, suggesting response movements by predators to prey distributions. Simulations show that predators have higher encounter rates when adopting Levy- type foraging in natural- like prey fields compared with purely random landscapes. This is consistent with the hypothesis that observed search patterns are adapted to observed statistical patterns of the landscape. This may explain why Levy- like behaviour seems to be widespread among diverse organisms(3), from microbes(8) to humans(9), as a `rule' that evolved in response to patchy resource distributions.

KW - SOUTHERN ELEPHANT SEALS

KW - WANDERING ALBATROSSES

KW - PATTERNS

KW - ENVIRONMENT

KW - ZOOPLANKTON

KW - MOVEMENTS

KW - SUCCESS

KW - WALK

UR - http://www.scopus.com/inward/record.url?scp=39849092398&partnerID=8YFLogxK

U2 - 10.1038/nature06518

DO - 10.1038/nature06518

M3 - Article

VL - 451

SP - 1098

EP - 1102

JO - Nature

JF - Nature

IS - 7182

ER -