DAILY MOVEMENTS, HABITAT USE, AND SUBMERGENCE INTERVALS OF NORMAL ANDTUMOR-BEARING JUVENILE GREEN TURTLES (CHELONIA-MYDAS L) WITHIN A FORAGING AREA IN THE HAWAIIAN-ISLANDS

Depth-sensitive ultrasonic transmitters monitored the horizontal and v ertical movements of 12 juvenile (<65 cm carapace length) green turtle s (Chelonia mydas L.) in Kaneohe Bay, Oahu (Hawaii, USA). This site wa s chosen because of its accessibility, its importance as a foraging ar ea, and the high incidence (almost-equal-to 50%) of fibropapillomatosi s, a tumor disease of unknown etiology. Our objectives were to determi ne the daily movements, habitat use, and submergence intervals of norm al and tumor-bearing animals. The presence of tumors had no obvious ef fects on movement patterns or habitat use. All turtles remained within a small portion of the bay where patch reefs and shallow coral-covere d areas are common, and algal growth most abundant. During daylight, t wo normal and two tumor-bearing animals remained within known feeding areas, all other turtles studied stayed within deep mud bottom channel s or within crevices on the sides of reefs. All, except one tumor-bear ing turtle, moved up on to shallow patch reefs or shallow coral-covere d areas at night. Submergence intervals for both groups were short (ov er 90% were 33 min or less and none exceeded 66 min) compared to maxim um breath-hold times (up to 5 h) measured in the laboratory by earlier workers. Juvenile green turtles in Hawaii, therefore, most likely mai ntain aerobic metabolism while submerged and surface before oxygen sto res are significantly depleted. Tumor-bearing turtles had a higher fre quency of longer submergence intervals during the night, indicating th ey may have been somewhat less active at night. Normal turtles showed no such day-night difference.