The pursuit strategy of predatory bluefish

A predator's ability to capture prey depends critically on how it coordinates its approach in response to a prey's motion.
Flying insects, bats, and raptors are capable of capturing prey with a strategy known as parallel navigation, which allows a predator to move directly toward the anticipated point of interception. It is unclear if predators using other modes of locomotion are capable of employing this strategy when pursuing evasive prey. Using kinematic measurements and mathematical modeling, we tested whether bluefish (Pomatomus saltatrix) pursue prey fish (Fundulus heteroclitus) with parallel navigation. We found that the directional changes of bluefish were not consistent with this strategy, but rather were predicted by a strategy known as deviated pursuit. Although deviated pursuit requires few sensory cues and relatively modest motor coordination, a comparison of mathematical models suggested negligible differences in path length from parallel navigation, largely due to the ...