Piscivorous cyprinid fish modulates suction feeding kinematics to capture elusive prey.

Previous studies have shown that evasive prey generally elicit a different kinematical pattern of prey capture from suction feeding fish compared to non-evasive types of prey. However, no evidence exists that predatory fish can modulate their prey capture kinematics in response to whether or not an elusive prey performs an escape response. Here, we analyse prey capture kinematics of a specialist piscivore (asp, Aspius aspius) during feeding on untethered, live goldfish, which regularly displayed escape attempts when attacked by the asp. Significant modulation occurred in function of the escape attempts of prey: mouth opening was prolonged and increased in magnitude, and one individual also showed an increased hyoid depression when feeding on prey trying to escape. As the orientation of the prey with respect to the predator prior to the start of mouth opening was related to the probability of observing an escape attempt, asp could theoretically perform this type of modulation by a priori choosing a pre-programmed motor pattern. However, since contact between the prey and the asp's mouth appeared to be a factor improving the timing of mouth closing, this fine-tuning of prey capture kinematics is more likely to be caused by reflexive neural feedback control.