Developmental changes in the blood oxygen transport system of Kemp's ridley sea turtle, Lepidochelys kempi

Abstract

Lepidochelys kempi is the most endangered of the seven species of sea turtles. Very little is known about the developmental rate or blood oxygen system of this diving species. Lepidochelys kempi of various ages (4 months to 10 years) were sampled for changes in hematocrit, hemoglobin concentration and components, and concentrations of organic phosphates in red blood cells as indices of the developmental rate of the oxygen delivery system. The major increase in both hematocrit and hemoglobin concentration occurs between 4 and 7 months. By 7 months all traces of an "embryonic" hemoglobin component are gone. A distinct but minor hemoglobin component appears in turtles older than 28 months. At all ages the major organic phosphate in red blood cells is adenosine triphosphate. The level is highest at 4 months, and decreases until 28 months, when it is statistically equal to that found in adult turtles. The level of 2,3-bisphosphoglycerate is highest at 4 months, then drops to the adult level by 28 months. Inositol pentaphosphate slowly increases, reaching the adult level at 19 months. It takes L. kempi approximately 2 years to acquire the blood oxygen system of an adult turtle as measured by these parameters. This developmental pattern is compared with that known for other sea turtles. The possible physiological significance of organic phosphates in sea turtle red blood cells is discussed.