Meeting Abstract

S1-2.9  Jan. 4  Going with the flow: rheotaxis and station holding in the shiner surfperch (Cymatogaster aggregata). VAN TRUMP, W.J.; Univ. of California, Irvine wvantrum@uci.edu

Shiner surfperch (Cymatogaster aggregata) contend with the fast and rapidly changing currents of an intertidal environment. The aim of the present study was to determine the functional role of the lateral line in the rheotaxis and station holding ability of C. aggregata. The kinematics of swimming were measured in fish in a flume under illuminated, and darkened conditions with both the lateral line intact and blocked with ototoxic antibiotics. I found that C. aggregata is capable of rheotaxis at very slow speeds (<0.5 cm/s, <0.08 BL/s). The ability to orient to slow flow was enhanced when fish were permitted to school. However, schooling reduced station holding ability. The effects of schooling were diminished under darkened conditions. These results suggest that visually mediated social behaviors influence the ability of fish to respond to flow. When observed in the dark, however, no reduction in the absolute ability to respond to flow was found, either in group trials or when tested individually. Additionally, no reduction in rheotaxis or station holding was seen after inhibition of the lateral line. This suggests that station holding and rheotaxis in C. aggregata may be achieved by utilizing sensory systems other than vision or lateral line hydroreception, such as olfaction or the vestibular response.