Janssen, J., 1997.  A Comparison of the Sensitivity of the Ruffe and Yellow Perch Lateral Lines to Daphnia and Hexagenia, Loyola University

A Comparison of the Sensitivity of the Ruffe and Yellow Perch Lateral Lines to Daphnia and Hexagenia

ABSTRACT
The ruffe (Gymnocephalus cernuus) and the yellow perch (Perca flavescens) have very different cephalic lateral line systems. The ruffe, which is nocturnal and frequents turbid water, has a cephalic lateral line with very wide canals, large neuromasts, and membranes covering the canal openings. This anatomy is convergent with many deep sea fishes. The yellow perch has a lateral line composed of neuromasts enclosed in narrow canals freely open to the water. This anatomy is typical of active, diurnal, shallow water fishes. Using infrared video in the dark, I found that ruffe detected Daphnia magna and the mayfly Hexagenia limbata at a greater distance than did yellow perch. Ruffe also swam faster than yellow perch while searching for prey. Swimming of ruffe consisted of a thrust by the pectoral and caudal fins followed by a glide; prey were detected during the glide phase. Yellow perch were usually immobile when they detected Daphnia. When searching for mayflies, yellow perch were swimming, but not in the thrust and glide pattern of the ruffe. It is suggested that the membranes over the openings in the ruffe's lateral line function to eliminate self-generated laminar flow "noise" from reaching the neuromasts. Non-laminar flows such as those created by stream turbulence or fast swimming are expected to compromise lateral line function in the ruffe more than in the yellow perch.

Contact: John Janssen, Biology Department, Loyola University, 6525 North Sheridan, Chicago, IL 60626 or jjanse@orion.it.luc.edu
Keywords: Ruffe, Basic_biology, Predators
Product Type: Publications, Conference_proceedings
User Type: General