Variable Kinematics of Sacramento Perch (Archoplites interruptus) Capturing Evasive and Nonevasive Prey

Kinematic analysis of the prey attack behavior of Sacramento perch (Archoplites interruptus) for familiar nonevasive prey (Daphnia magna), and for novel evasive prey (Diaphanosoma brachyurum) was undertaken using video taping. The fish use two distinct attack modes. The attack on nonevasive prey is characterized by leisurely approach and relatively conservative attack motions. Attacks on evasive prey are very vigorous and energetically more demanding. Vigorous attacks on the evasive prey which were successful 55% of the time required approximately four times as much energy per attack as did the always successful attacks on the nonevasive prey. Differences between the evasive and nonevasive prey were rapidly learned as shown by the development of the vigorous attack in naive fish, which generally occurred in 10–20 encounters.Key words: predation, behavior, learning, evasion, kinematics, Archoplites interruptus