81.3 Friday, Jan. 6 The diversity of strike kinematics in serranid fishes: support for the ram-suction continuum OUFIERO, Christopher E.*; HOLZMAN, Roi; WAINWRIGHT, Peter C.; Univ. of California, Davis firstname.lastname@example.org
Suction feeding, the most common form of prey capture in fish has been well characterized in relation to its biomechanics and morphology; yet, little is known about the underlying constituents for the diversity in this trait. We used principal component analysis to determine the major axes of variation in kinematics, morphology, and mechanics of suction feeding across 30 species of serranid fishes. We also examined correlations among traits to test for expected trade-offs. Prey capture sequences using fish prey were filmed at 1000 Hz. Between 5-10 sequences were filmed for 1-5 individuals per species for a total of 227 sequences. We tracked 11 landmarks throughout each sequence, generating 18 kinematic variables. Body size-corrected species means of traits were used in the PCA. PC1 (30%) distinguished species with a longer strike distance, fast ram speed, high head and lower jaw rotations from species with shorter, slower strikes with less movement; PC2 (24%) was a speed/timing trade-off axis and PC3 (18%) was correlated positively with suction index, lower jaw opening mechanical advantage, residual gape and jaw protrusion. In contrast to common expectations we found no significant correlation between ram speed and maximum jaw protrusion (r = 0.21, p = 0.26) or lower jaw opening mechanical advantage and jaw opening speed (r = 0.04, p = 0.83). However, we did find a significant trade-off between suction index with ram speed (r = -0.38, p = 0.04) and residual strike distance (r = -0.42, p = 0.02), which was also supported in the PCA. These results support the proposed ram-suction continuum, whereby a negative correlation between ram speed and suction reflects alternative strategies for closing the final distance between the predator and prey.