Meeting Abstract

P2.75  Jan. 5  Feeding Performance of Juvenile Red Snapper (Lutjanus campechanus) From Two Habitats CASE, JE*; MARSHALL, CD; Texas A&M University @ Galveston casejanelle@neo.tamu.edu

Juvenile red snapper are attracted to structure and settle onto low profile reefs, which serve as nursery grounds. Little is known about their biology during this time. Recent studies from a shell bank in the NW Gulf of Mexico have shown higher growth rates for fish located on adjacent mud habitats, perhaps due to varied prey availability and abundance. For this study juveniles were collected from a shell ridge (on ridge) and adjacent mud areas (off ridge) on Freeport Rocks, TX. Feeding morphology and kinematics were characterized and compared between the two habitats. A dynamic lever model was used to make predictions about feeding mechanics, and was validated using kinematic profiles obtained from high-speed videos of prey capture events. The model reasonably predicted kinematic profiles of jaw closure for maximum gape velocity and displacement. Model output suggested that on ridge fish have faster jaw closing velocities than off ridge fish. Off ridge fish therefore have greater mechanical advantage and longer closing durations. Analysis of prey capture events indicated that on ridge fish demonstrate greater velocities and larger displacements of the jaws than off ridge fish. Shape analysis was used to further investigate habitat effects on morphology. Off ridge fish differed from on ridge in possessing a deeper head and body. Results from model simulations, kinematic profiles, personal observations, and shape analysis all compliment the conclusion that on ridge fish exhibit suction feeding behavior, whereas fish from off ridge use biting behavior. These results suggest that habitat disparity, perhaps available prey composition, has generated variations in feeding mechanics and consequently feeding behavior. This may ultimately affect growth rate and indicate nursery quality.