Meeting Abstract

P2.65  Monday, Jan. 5  Gait diversity in juvenile labroid fishes KING, HM; NEUBARTH, N*; HALE, ME; Univ. Chicago; Univ. Chicago; Univ. Chicago hking@uchicago.edu

Juveniles of a number of labroid fish species, specifically pomacentrids, scarids, and labrids, use pectoral fin-based locomotion during steady swimming. At low speeds they alternate the pectoral fins and they use synchronous pectoral fin movement at high speeds. Above a critical speed they tuck the fins and power swimming with axial bending alone. We examine swimming gaits in juveniles of a related group, the cichlids. Cichlids also belong to the suborder Labroidae, and their morphological diversity provides opportunities to examine locomotor variation across a diverse range of morphologies and ecologies. We hypothesized that juvenile Labeotropheus sp. would use the same locomotor modes as juveniles of other members of Labroidae. Young fish were obtained from a local breeder. Fish were filmed at 250Hz in a flow tank at a range of speeds. A ventral view was used to determine fin/axial patterns and a lateral view was used to determine the location of the fish in the water column. Juvenile Labeotropheus exhibited an alternating pectoral fin gait at low speeds and transitioned to a synchronous pectoral fin gait at higher speeds. Both gaits were coordinated with axial undulation. In the alternating gait, pectoral fin movement was 180 out of phase with caudal bending. During synchronous pectoral fin movement, each tail beat cycle was associated with two pectoral fin beats so that each pectoral fin was alternately in phase and 180 out of phase with caudal bending. While there are similarities between the pectoral fin gaits of juvenile Labeotropheus and other labroid species, coordination of the pectoral fin with the body axis differs markedly indicating that there is considerably more diversity of swim coordination patterns in juvenile labroids than previously described. Supported by NSF grant IBN0238464 to MEH.