Meeting Abstract

P3.17  Tuesday, Jan. 6  Estimate of Survival Time of Diamondback Terrapins Caught in Crab Traps Based on Voluntary Dive Times and Metabolic Rates THOMSON, Amy*; VATNICK, Itzick; BAKER, Patrick; Widener University; Widener University; Swarthmore College amthomson@mail.widener.edu

Mortality in commercial crab traps has contributed to the decline of local populations of the diamondback terrapin, Malaclemys terrapin. It is unknown how long a terrapin can survive after entering a submerged crab trap. For this reason, behavioral and physiological analyses were conducted to estimate survival time. Average (Mean +/- SD) voluntary dive time (8.4 +/- 5.7 min; n = 9) of captive terrapins was determined by videotaping animals in the laboratory. Females (9.2 +/- 6.8 min; n = 5) generally had longer dives than males (7.4 +/- 3.4 min; n = 4) and dive length was not correlated with body mass. The longest voluntary dive was 50 minutes. In contrast, the average time of submergence for seven crab traps set in tide creeks over a 4-day period was 58 +/- 54 min for morning high tides and 314 +/- 61 for evening high tides. Oxygen consumption was determined at 10, 20 and 30 °C. As expected, metabolic rate increased with temperature (Q10 = 1.73). Using mass-specific lung volume and metabolic rates, it was calculated that a ~200g terrapin in this study had enough oxygen stores to sustain aerobic metabolism for ~ 11 min at 25°C. Therefore, our data seem to indicate that voluntary dives in the laboratory are terminated before the anaerobic diving threshold has been reached. Because commercial crab traps are likely submerged for several hours at high tide, terrapins that are accidentally caught in these traps must rely extensively on their ability to sustain anaerobic metabolism to avoid drowning.