TURINGAN, R. G.; BECK, J. L.: Predator-prey interactions in the marine plankton: functional and morphological bases of prey-capture performance in marine fish larvae

Our knowledge of the relationship between feeding functional morphology and prey-capture performance in marine fish larvae is limited compared to our knowledge of juvenile and adult fish feeding ecomorphology. The central theme of this study is based on two major findings of previous investigators. First, that variation in swimming behavior of zooplankton prey could potentially influence prey-selection in marine fish larvae. Second, that the feeding mechanism of marine fish larvae develops from a simple, hyoid-driven system (i.e., the hyoid stage) to a more complex system that involves the opercular-mandible couplings, in addition to the hyoid mechanism (i.e., the operculo-hyoid stage). This study tests the central hypothesis that stage-specific change in the complexity of the biomechanical design of the feeding mechanism underlies the ability of marine fish larvae to capture their planktonic prey. Results of pilot studies on the functional morphology of the feeding mechanism, feeding performance, and feeding kinematics in marine fish larvae revealed that: (1) the hyoid apparatus mediates lower-jaw depression in first-feeding larvae, (2) hyoid-stage larvae feed on small, less elusive plankton, and (3) movement of the hyoid is synchronous with lower-jaw excursions during mouth opening in first-feeding larvae. The structural and functional design of the feeding apparatus underlies the ability of marine fish larvae to capture prey. Thus, understanding the performance consequences of the development of the feeding mechanism is crucial to our understanding of the causes of starvation during the early-life history stage of marine fishes.