Effects of overwintering temperatures on the escape response in cunner (Tautogolabrus adspersus).

Abstract

Cunner (Tautogolabrus adspersus) are a temperate labrid species that inhabit the Western Atlantic and experience temperatures ranging from 0°C to 25°C. During autumn, once temperatures drop below 10°C in Long Island Sound, cunner find shelter and enter a state of quiescence. Previous work has shown that acclimation to low temperatures limits the performance of locomotor musculature, which significantly lowers steady swimming capabilities. We aimed to understand how the escape response (C-start) might be impacted by temperatures experienced by cunner in Long Island Sound over the course of a year. Escape responses were recorded at 250 frames/s at 20°C, 15°C, 10°C, and 5°C. Average peak velocities and accelerations were faster in fish acclimated to 20°C than to 5°C and 10°C. Despite taking a similar turn angle to 10°C and 15°C fish, the 5°C treatment group took longer to complete the C-start, which might make them more susceptible to predation at this temperature. Based on these results it appears that the escape response is reduced at cold temperatures. Previous research has shown that locomotor musculature performance is significantly reduced at cold temperatures, which could explain the results seen here. The decrease in escape performance at cold temperatures could explain their state of extended torpor as the slowed C-start at these cold temperatures might make them more susceptible to predation.