Meeting Abstract
Pelvic and pectoral fins play major roles in both controlling how a fish moves itself, and its ability to station-hold. However, the effect that the morphology of these fins has is something that isn’t as well understood. This study examined the relationship between fin shape and locomotion in six species of sympatric Etheostoma darter fish, which will provide a clearer picture of the ecological niches of the six species examined. We measured slip speed and fin angle during four different types of movement: hovering, ascending, descending, and braking. These tests were performed in a 5’x1’x1′ unidirectional flume, with a gravel substrate, and recorded with a high speed digital camera at 250 frames per second. The shape of the fins was described using geometric morphometrics, in order to more accurately quantify any differences in shape. The fish were dissected in order to remove the adductor and abductor superficialis muscles to identify the effect of muscle mass. Regression analysis was used to determine whether there is a significant relationship between fin shape and locomotion. Based on the results of previous studies, we believe that larger pelvic and pectoral fins, such as those seen in Etheostoma variatum, will result in generally higher slip speeds, and also believe that larger pectoral fins will show smaller fin angles in the fin angle tests. Having a greater understanding of these species’ ecology could improve preservation efforts, as other sympatric darters in this stream are threatened or endangered.
