Page 335 - Hawaii: Diving, Surfing, Pearl Harbor, Volcanoes and More

Predation and Disease

urtles are highly vulnerable to predation the exposure time to predators. Predation by
T and the kind of predator depends on their fish during the early morning hours is greater
developmental stage. Eggs are most suscepti- than at night (Mann, 1977; Limpus, 1978). Crabs,
ble to predation even if they are safely buried, particularly ghost crabs (Ocypode sp.), are per-
because of their long incubation period. Sand haps the most efficient nocturnal predators of
or ghost crabs often burrow into the nest and hatchling sea turtles (Raymond, 1984).
eat the eggs, and the resultant tunnel provides
access to additional predators such as dipterous esting turtles become easy prey on land
maggots and ants. They may also be eaten by Nbecause of their sluggishness. Feral mam-
varanid lizards and terrestrial mammals. Fungal mals may hurt them and take on their eggs
and bacterial infections are also common. but such predation is minimal. Man is the most
explicit example of a predator. Green turtles in
pon emerging from the sand, hatchlings Hawaii, Florida and Bahamas have been found
Uare usually preyed on by ghost crabs, develop fibropapillomas that appear as lobe-
which by instinct know that the part of the like tumors, that grow primarily in the skin but
body to be damaged first are the eyes (Mros- can also appear between scales and scutes, in
ovsky, 1968). Sea birds and varanid lizards also the mouth, eyes and on the internal organs.
prey on the little hatchlings. While in the water, These tumors are debilitating. The cause and
predation continues, by birds at the surface and mode of transmission is yet unknown. Different
fishes in the water column. Sharks are formida- species of barnacles have been found to infest
ble enemies throughout the life cycle of marine turtles
turtles. Any hatchling disorientation increase