CARROLL, Andrew M.; WAINWRIGHT, Peter C.; HUSKEY, Stephen H.; COLLAR, David C; TURINGAN, Ralph G.; Univeristy of California, Davis; Univeristy of California, Davis; Western Kentucky University; Univeristy of California, Davis; Florida Institute of Technology: Force transmission during suction feeding in centrarchid fish.

Suction feeding fish differ in their capacity to generate subambient pressure while feeding, and these differences appear to relate to morphological variation. We developed a morphological model of force transmission in the fish head and parameterized it with measurements from individual fish. The model was applied to 45 individuals from five species of centrarchid fishes: Lepomis macrochirus, L. punctatus, L. microlophus, Micropterus salmoides, and Pomoxis nigromaculatus. Measurements of epaxial cross-sectional area, epaxial moment arm, buccal area and buccal area moment arm were combined to estimate pressure generation capacity for individual fish. This estimation was correlated with pressure measured in fish feeding on elusive prey to test the model�s ability to predict pressure generation from morphology. The model explained differences in pressure generation found among individuals (P<0.001; r2=0.71) and produced a realistic estimate of normalized muscle stress during suction feeding (68.5�6.7 kPa). These results reveal a direct trade-off between morphological requirements of feeding on larger prey (larger mouth size relative to body depth) and the ability to generate subambient pressure while suction feeding on elusive prey. The model can also be used to calculate muscle force in vivo during feeding, allowing the estimation of the muscular power required for explosive suction feeding.