Meeting Abstract
71.4 Tuesday, Jan. 6 Muscle mass limtis suction feeding performance among three centrarchid species. CARROLL, Andrew M.*; HUSKEY, Steve; WAINWRIGHT, Peter C.; University of Evansville, Evansville, IN ac204@evansville.edu
The influence of musculoskeletal design on suction feeding performance (i.e. volumetric expansion and sub-ambient pressure generation) is not quantitatively or generally established. It has been hypothesized that mechanical work and power, and thus suction feeding performance are limited by available energy from suction feeding muscle contraction. Here, we measured external kinematics, buccal sub-ambient pressure, and available epaxial muscle volume to determine whether available muscular capacity in fact limits suction feeding performance. Silicone casts of buccal dimensions were used to estimate internal buccal volume change from external kinematics (videoed at 500 or 1000 Hz), while sub-ambient pressure was measured directly. Measurements where made on a broad size range of individuals from three species of centrachid fishes, largemouth bass (Micropterus salmoides), bluegill sunfish (Lepomis macrochirus), and green sunfish (Lepomis cyanellus), feeding on evasive prey. Muscle mass was found to have a strong correlation with mechanical work (r=0.85; p<0.001) and power (r=0.83; p<0.001). The slopes of these correlations where found to be realistic estimates of mass-specific muscle work (11.82 J Kg-1) and power (634127 W Kg-1). Interestingly, the relative proportion of suction feeding muscle to body mass was found to strongly correlate with suction feeding work (r=0.84; p<0.01) and power (r=.88; p<0.01) among <i>Lepomis individuals (but not when Micropterus were included). Finally, a strong (r=0.81; p<0.001) trade-off between sub-ambient pressure magnitude and volume was found, but only when the latter was normalized to available muscle mass. Thus, suction feeding fish are limited first by their proportion of available muscle mass available for suction feeding, then by the trade-off between volumetric expansion and sub-ambient pressure production.
