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How marine predators 'walk' to find food

Posted on 4 April 2008

The natural world is unpredictable, so how can we ever hope to exploit it sustainably? This question forms a major area of study in the York Centre for Complex Systems Analysis (YCCSA), a multi-disciplinary centre which studies complexity science. Complexity science uses mathematics and computational modelling to study the behaviour of systems across diverse scales and applications.

A nursing shark feeding: image by Richard Ling

Staff recently collaborated in an international research project which used dive data collected from marine predators such as sharks, tuna, cod, sea turtles and penguins, in various locations around the world. These data were compared with the distribution patterns of the animals’ prey, leading to the development of a computer model which was used to identify optimal marine predator search behaviour.

The research showed that marine predators forage for food in a similar search pattern to the way many people shop in supermarkets. The animals’ behaviour seems to have evolved as a general 'rule' to search for sparsely distributed prey in the vast expanse of the ocean. This rule involves a pattern of random movement known as a Levy Walk, where the predators use a series of small motions interspersed with large jumps to new foraging locations. This increases the chance of finding food, however widely scattered it might be.

A practical application of this work is finding sustainable ways of managing fisheries, and in particular to understanding whether marine reserves can be effective in European waters. By analysing the movement of individual fish, YCCSA researchers hope to identify the key parameters for strategic marine reserve models for the North Sea.

Sea turtle: photo by Bemep

An exciting feature of complexity science is in spotting mathematical similarities between seemingly unrelated phenomena at diverse scales. Researchers in YCCSA are currently investigating the ideas of probabilistic Levy processes for modelling superspreading in epidemics such as SARS, identifying how plant roots forage for nutrients, and trying to understand why some plankton move in mysterious ways.

 

About the researcher

 Dr Jon Pitchford is a lecturer in the Department of Mathematics and works in York Centre for Complex Systems Analysis (YCCSA)

Contact

Email: jwp5@york.ac.uk

http://maths.york.ac.uk/www/jwp5

Further information