Long‐Term Cold Acclimation Leads to High Q10Effects on Oxygen Consumption of Loggerhead Sea TurtlesCaretta caretta (original) (raw)
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Corticosterone and Thyroxine in Cold-Stunned Kemp's Ridley Sea Turtles ( Lepidochelys Kempii )
Journal of Zoo and Wildlife Medicine, 2012
Kemp's ridley sea turtles (Lepidochelys kempii), a critically endangered species, frequently strand on the shores of Cape Cod (Massachusetts, USA) in late autumn in a state of ''cold-stunning'' exhibiting low body temperature and related clinical issues. Stranded turtles are transported to the New England Aquarium (Boston, Massachusetts, USA) for treatment and rehabilitation. This study tested the hypothesis that cold-stunned sea turtles might exhibit high corticosterone (''stress hormone'') or low thyroxine (which is often affected by temperature), or both, and that monitoring of both hormones may be useful for assessing recovery. In a retrospective analysis, 87 archived plasma samples were assayed from 56 cold-stunned juvenile Kemp's ridley sea turtles for corticosterone and free thyroxine (fT4). Upon admission, mean corticosterone was the highest yet reported for a population of sea turtles (39.3 6 2.5 ng/ml; mean 6 standard error of the mean [SEM]) and fT4 was usually undetectable. On admission, corticosterone was negatively correlated with white blood cell count but was not correlated with blood glucose. There were no differences in either hormone between survivors and nonsurvivors on admission. After 18þ days in recovery, surviving turtles' corticosterone dropped significantly to levels typical of baseline in other species (0.9 6 1.0 ng/ml) while fT4 increased significantly (1.3 6 1.5 pg/ml). During recovery, corticosterone was positively correlated with blood glucose and was not correlated with white blood cell count. Turtles that showed persistent deficits in feeding, activity, or both during recovery had significantly lower fT4 than did turtles with no such deficits. The ''high corticosterone, low fT4'' endocrine profile seen on admission may be a useful marker of cold-stunning in this and other species. Further studies are necessary to determine whether low thyroid hormones play a causal role in deficits in feeding and activity during recovery. Monitoring of both hormones may be useful for triage, monitoring of recovery, and assessing readiness for release.
2020
Sea turtles annually migrate to the coasts of the Northeastern United States, venturing farther north every year along the Gulf Stream into the Gulf of Maine. During the warmer months, sea turtles utilize the nutrient-rich waters of New England before migrating south as Fall approaches. However, many of these individuals cannot navigate out of Cape Cod Bay due to the geographic configuration of Cape Cod’s eastern shorelines, which create a land barrier and prevent sea turtles from accessing open waters. These sea turtles, particularly the critically endangered Kemp’s ridley (Lepidochelys kempii), become cold-stunned as water temperatures decline. The cold-stunned sea turtles that do not survive provide valuable opportunities for scientific research that allows for a better understanding of how these animals are interacting with Cape Cod habitats. Literature elaborating the biochemistry of sea turtles is very limited, despite the crucial value of this information in understanding the...