Page 607 - The British Big Four

Predation and Disease

T urtles are highly vulnerable to predation time to predators. Predation by fish during the
and the kind of predator depends on their early morning hours is greater than at night
developmental stage. Eggs are most susceptible (Mann, 1977; Limpus, 1978). Crabs, particularly

to predation even if they are safely buried, be- ghost crabs (Ocypode sp.), are perhaps the most

cause of their long incubation period. Sand or efficient nocturnal predators of hatchling sea

ghost crabs often burrow into the nest and eat turtles (Raymond, 1984).

the eggs, and the resultant tunnel provides ac-
Ncess to additional predators such as dipterous
esting turtles become easy prey on land be-
maggots and ants. They may also be eaten by cause of their sluggishness. Feral mammals

varanid lizards and terrestrial mammals. Fungal may hurt them and take on their eggs but such

and bacterial infections are also common. predation is minimal. Man is the most explicit

Upon emerging from the sand, hatchlings example of a predator. Green turtles in Hawaii,
are usually preyed on by ghost crabs, which Florida and Bahamas have been found develop
fibropapillomas that appear as lobe-like tumors,

by instinct know that the part of the body to be that grow primarily in the skin but can also ap-

damaged first are the eyes (Mrosovsky, 1968). pear between scales and scutes, in the mouth,

Sea birds and varanid lizards also prey on the lit- eyes and on the internal organs. These tumors

tle hatchlings. While in the water, predation con- are debilitating. The cause and mode of trans-

tinues, by birds at the surface and fishes in the mission is yet unknown. Different species of bar-

water column. Sharks are formidable enemies nacles have been found to infest turtles

throughout the life cycle of marine turtles. Any

hatchling disorientation increase the exposure