Page 331 - Hawaii: Diving, Surfing, Pearl Harbor, Volcanoes and More

Eggs and Hatchlings - Danger is Everywhere

pproximately a month after the last dropped one, or two or three at a time and biotic (roots, microbial flora, predators,
A mating, the female turtle emerges the eggs are covered with mucus when nesting turtles) components of the nesting
from the sea to lay her several clutches of they leave the cloaca. A few abnormally habitat Limpus, 1994). The average incu-
eggs. The season and frequency of nest- small or non-spherical eggs are usually bation of eggs ranges from 45 - 75 days,
ing among female depends on individual found in each nest. depending on the temperature.
populations and the species of turtles.
he eggs incubate in the sand and the uring incubation, or immediately
emales lay their eggs high up on the T hatchlings must dig their own way up D following emergence from the nest,
F beach, usually within the vegetative from the nest after a successful incubation. the hatchling is imprinted on to the earth’s
strand. Prior, the eggs contain a pinhead- Incubation period is an inverse function magnetic field at the rookery and possibly
sized embryo that has developed to of nest temperature: higher temperatures also to the rookery’s olfactory character-
mid-gastrulation. Further development is result in shorter incubation period within istics. Responding to visual cues which
stopped a couple of days before the nester embryonic tolerance limits. Lower temper- guide it seaward as well as by orienting
comes ashore to lay the eggs. The embryo atures result in an increase in the incuba- towards wave fronts, the hatchling is
will not develop further until the eggs are tion period by retarding the rate of de- directed out into open water and away
laid. While the eggs are deposited into the velopment. Cool temperatures may cause from the coast. Sea turtle hatchling usu-
egg chamber, they are tolerant to bounc- some morphological and/or metabolic ally emerge from their nests at night, on
ing, rolling, tumbling or handling. How- problems depending on which stage of early mornings or after the rains, when the
ever, two hours after laying, the embryo development they occur. Exposure to high temperature is relatively low. Nocturnal
will resume development and a simple roll temperatures results in malformation of emergence is advantageous to hatchlings
of the egg is enough to kill the develop- the embryo, especially in the first trimes- in a number of ways. First, there is lesser
ing embryo. Marine turtle eggs resemble ter. Incubation success is a function of the exposure to the intense heat of day which
the shape and color of table tennis balls. physico-chemical (temperature, moisture can easily be fatal to them.
During oviposition, the eggs are usually content, salinity, gaseous exchange) and