P2.151 Thursday, Jan. 5 Characterization of the Rostrum Lateral Line of Juvenile Paddlefish (Polyodon spathula) KRUEGER, J.A.*; ROBERTSON, J.C.; Westminster College, PA firstname.lastname@example.org
Paddlefish (Polydon spathula) are found predominantly in the Mississippi River drainage basin and are characterized by the prominent rostrum that extends from their cranium. While not present at hatching, the rostrum appears quickly and grows rapidly in juvenile paddlefish. The rostrum is covered superficially by electroreceptors that respond to electrical signals emitted by planktonic prey and are used in feeding. Our studies have identified an internal lateral line canal system that extends from base to tip in the paddlefish rostrum. Lateral lines function in sensing hydrodynamic stimuli in water. Neuromasts are the receptive elements of the lateral line that detect vibrations or movement in water originating from prey, predators, other fish, or environmental obstacles. The objectives of this work are to describe and characterize the lateral line canal in the rostrum of juvenile paddlefish. We examined H&E stained slides of cross sections of rostrums; three sections of the rostrum of six juvenile paddlefish of uniform body length were examined. The three sections were obtained from standard locations at points 25%, 50% and 75% along the eye-to-tip length of each rostrum, allowing for comparison of the lateral line at different locations along the rostrum. An image analysis program was used to obtain measurements of different features of the rostrum lateral line. These measurements include canal diameter, canal area, and the cross-sectional heights of sensory cells and canal wall cells. Qualitative observations additionally allow comparison of the paddlefish rostrum system with the lateral line canals of other species. This work furthers understanding of the functional anatomy and sensory biology of the paddlefish rostrum and may be of use in ongoing efforts to conserve paddlefish.