LICAMELE, Jason D; TURINGAN, Dr. Ralph; Florida Institute of Technology: Linking development of prey selectivity and feeding functional morphology in marine fish larvae.

Extensive collection of marine fishes by the commercial food and marine ornamental industries has accounted for the observed decline in populations and a decrease in overall body size of marine fish. Success in captive culture of marine-fish species is hindered by the ability to provide fish larvae with an appropriate size and nutritional feed during the critical period of first feeding. This phenomenon creates a need for research that will lead to our understanding the processes that drive feeding performance in marine fish larvae. The mechanism for opening the mouth in early marine fish larvae is driven by protrusion of the hyoid and cranial rotation (hyoid stage). Throughout ontogeny marine fish larvae undergo a change in their feeding mechanism from the simple hyoid stage, to a more complex and efficient hyoid-opercular stage. The hyoid- and opercular series linkages (hyoid-opercular stage) incorporate the expansion of the operculum coupled with hyoid depression to create a more efficient and adult-like feeding mechanism. This hyoid-opercular stage is a more efficient process enabling larvae to consume more prey, larger prey, and a greater variety of prey thus increasing their feeding efficiency and ultimately increasing growth and survival. This study investigates prey-selectivity and feeding mechanics in P. aldabraensis larvae, from the early hyoid stage (0-15 D.P.H) to the hyoid-opercular stage (15+ D.P.H.). The increased presence of Artemia (4.4 Artemia/fish) in the gut of older larvae indicates a change in feeding capability. An increase in average prey consumed (8 prey items/fish) indicates an increase in feeding efficiency. Maximum gape does not limit prey consumption. We therefore hypothesize that prey selection is limited by the overall functional capability of the oral jaw mechanism in marine fish larvae.