Meeting Abstract

58.4  Thursday, Jan. 6  Just swim away: the C-start escape response in four species of surfperches (Embiotocidae) from central California PERLMAN, B.M.; Moss Landing Marine Laboratories perlbm0@wfu.edu

Surfperches exhibit a C-start escape response to avoid disturbances, such as predators. This fast-start response consists of bending their body into a “C” shape, immediately followed by swinging their tail in the opposite direction to propel away from a stimulus. I hypothesized that barred, shiner, black, and pile surfperches would differ in their escape response due to variations in their fin morphology. Fishes with a higher fin angle and lower aspect ratio (AR) of the pectoral fin were predicted to turn faster and achieve greater bending than fishes with lower fin angles and higher AR. I collected four species with varying pectoral fin angles and AR and elicited C-starts from individual fish, recording the escape response with a high-speed digital camera at 250 fps. I measured the maximum angle of body curvature during Stage 1 and 2, duration of Stage 1 and 2, duration of the entire C-start escape response, escape trajectory angle (ETA), and peak angular velocity. I conducted a PCA on the seven variables to reduce the dimensionality of the dataset. ANOVA was then performed on the principal component scores (PCs), followed by LSD post hoc tests to reveal where significant differences, if any, occurred. PC1 described duration of Stages 1 and 2, Stage 1 angle, total escape response duration, ETA, and peak angular velocity. PC2 described Stage 1 angle and duration, and ETA. PC3 described Stage 2 angle. Shiners (46° fin angle; 2.63 AR) had the fastest response with piles (51° fin angle; 4.24 AR) being the slowest and least maneuverable. Barreds (35° fin angle; 3.16 AR) achieved the greatest body curvature and the second fastest response time. Morphological differences among these species seemed to be part of the reasons for the varying performances in the C-start escape response.