Meeting Abstract

P2-23   -   Thermal impacts on fish jaw musculature performance Moran, C/J*; Olczak, L/G; Gerry, S/P; The Citadel; Fairfield University; Fairfield University cmoran3@citadel.edu

The sternohyoideus and adductor mandibulae are the primary jaw opening and closing muscles in fishes. While critically important to the success of fishes, the contraction kinetics of these two muscles is rarely addressed. We aimed to describe the contraction kinetics of the sternohyoideus and the adductor mandibulae in response to changing water temperatures. In addition, we used the primary aerobic locomotor muscle of labrid fishes, the abductor superficialis, as a baseline comparison to previous studies. Using cunner (Tautogolabrus adspersus) captured from Long Island Sound, we analyzed in-vitro muscle performance using a muscle ergometer. We tested all three muscle types at 7, 15 and 22 °C. Contraction time and time to relaxation were similar among all muscles, while jaw musculature produced more relative force compared to locomotor musculature. We found that, despite distinct fiber type composition, differences in fiber performance was remarkably similar. Cold temperatures limited contraction performance but all three muscles responded to temperature changes similarly. While we expected comparable results for muscle contractions at the cold temperature treatment, the contraction performance similarities among muscles were surprising. We conclude that differences in fiber types are not enough to amount to single twitch and tetanic contraction differences. Perhaps if more sustained movement was required of the muscle, greater contraction dynamic differences may become apparent.