The responses of sea turtles to temperature changes : behavior, metabolism, and thyroid hormones /
| Main Author: | |
|---|---|
| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1992.
|
| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | To simulate the adaptational characteristics of sea turtles to cold in the wild, a series of experiments were conducted using captive sea turtles which have been maintained in constantly warm water temperature. Captive immature green, Chelonia mydas, and Kemp's ridley, Lepidochelys kempi, sea turtles showed depressed metabolism and activity in cold temperatures. Both species demonstrated that they are able to adapt to cold temperatures behaviorally and physiologically. Moreover, the two species appear to have different "strategies" to avoid cold temperature. The green turtle appear to behaviorally tolerate the onset of cold water temperatures, whereas the ridleys become very agitated and active as they are exposed to cold temperatures. However, both species displayed semi-dormant behavior in cold water at the temperatures below 15°C. Importantly, they did continue to come up to the surface to breathe periodically at intervals up to 3 hours. Plasma thyroid hormone levels and blood metabolic parameters, such as blood glucose, total protein, pO2, and pCO2 decreased with temperature, indicating slower metabolism in cold water. Under constant temperature, nutritional status affected plasma thyroid hormones and glucose level, but not protein level in green and Kemp's ridley turtles. Plasma T4 in green turtles decreased with deprivation of food, but did not do so in Kemp's ridleys. Increased feeding did not affect circulating levels of plasma T4 in either species. Plasma T3, in contrast, tended to decrease during fasting and increase with refeeding or increased feeding. Blood glucose level fell with deprivation of food, but remained constant during increased feeding. Sea turtles may use glycogen or lipid during short-term fasting as in endothermic vertebrates. In immature wild green and loggerhead, Caretta caretta, sea turtles, serum thyroid hormones appeared to be more or less associated with temperature. In contrast, captive adult Kemp's ridleys showed that serum thyroid hormones were associated with a reproductive status rather than temperature. It is suggested that the lower T4 levels in wild turtles relative to captive ones may be caused primarily by nutritional state... |
|---|---|
| Item Description: | Typescript (photocopy). Vita. "Major subject: Zoology." |
| Physical Description: | xxi, 174 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |