Increased turning per unit distance as an area-restricted search mechanism in a pause-travel predator, juvenile plaice, foraging for buried bivalves

During searching, discovery of a prey patch by juvenile plaice Pleuronectes platessa was associated with a change from extensive to intensive search behaviour several moves before an attack on a prey. Intensive search behaviour was characterized by reduced distance of moves, a greater rate of turning per unit distance and shorter pauses between moves. The increase in turn rate was associated with area-restricted seaching, while a decrease in distances moved suggests that plaice search more efficiently for prey when stationary than while moving. The klinokinetic mechanism that appears to regulate search behaviour in juvenile plaice should allow efficient exploitation of a range of prey distribution patterns based on localized cues alone. Such a mechanism is especially useful to a migratory predator, like plaice, whose foraging is subject to time constraints imposed by tidally available feeding areas. (C) 2000 The Fisheries Society of the British Isles.