Meeting Abstract

P3-57  Sunday, Jan. 6 15:30 – 17:30  Seasonal Changes in Pectoral Fin Muscle Histology in Temperate Labrid Fishes TRAVITZ, LS*; MORAN, CJ; GERRY, SP; COUGHLIN, DJ; Widener University, Chester, PA; The Citadel, Charleston, SC; Fairfield University, CT; Widener University, Chester, PA lstravitz@widener.edu

Cunner (Tautogolabrus adspersus) and tautog (Tautoga onitis) are temperate wrasses with different strategies for overwintering. While cunner enter torpor during winter, tautog migrate off shore into stable deep-water habitats. Previous work has shown significant decreases in muscle and locomotor performance at temperatures ≤10^°C. In the present study, we use immunohistochemistry with fast and slow myosin heavy chain antibodies to explore how the muscle fiber composition of the abductor superficialis varies across a range of thermal acclimation temperatures in these two species. The abductor superficialis powers the thrust-generating downstroke in these labriform swimming fishes. Preliminary analysis reveals that the bulk of this muscle is composed of a fast-twitch fibers while the slow-twitch muscle fibers are distributed in a discrete slip along one edge of the abductor superficialis. This work will explore how the relative amount of fast- and slow-twitch varies with thermal acclimation in cunner and tautog. To maintain performance in winter would require a relative increase in the contribution of fast-twitch fibers. For instance, tautog may differ from cunner in their pectoral muscle fiber distribution due to differences in over-wintering behavior.