Sea Turtle Awareness MonthKnow your ESS turtles!
The Green and Hawksbill turtles
The month of October has been dedicated as “Sea Turtle Awareness Month” by the
Environmental Management Authority (EMA). As part of the EMA’s ongoing efforts to protect
turtles through legislative, enforcement and educational measures, five sea turtles were
designated as Environmentally Sensitive Species (ESS) this year - the Green, Hawksbill,
Leatherback, Loggerhead, and Olive Ridley owing to their dwindling numbers and threatened
habitats. Most citizens may not be familiar with these ESS turtles and their characteristics. To
help you identify each turtle, here’s a brief synopsis of their unique features and nesting
grounds. This article features the Green and Hawksbill turtles.
Green Turtle (Chelonia mydas)
Green turtles occasionally nest on the shores of Trinidad, mainly on the north and east coasts,
and in Tobago. Their nesting period is believed to be between February and August each year,
and continues into September and October at Matura. This species is named for the greenish
colour of its body fat. The colour of their outer shell varies from light brown to dark brown,
sometimes with a hint of olive. Additionally, the shell has wavy dark marks with blotches of
dark brown. Their plastron or shell on the underside is yellowish in colour.
The adult green turtle weighs around 500 pounds and has a length of 80 cm to 150 cm. They
are generally found on broad expanses of shallow sandy flats covered with sea grass or
seaweed, and within coral reefs. Throughout the year they can be found in these near shore
habitats around Trinidad and Tobago.
Current estimates suggest the age of sexual maturity for the green turtle is 45 to 50 years.
Females migrate huge distances between feeding grounds and nesting areas, but tend to follow
coastlines rather than to cross open waters. An individual female nests approximately every 3
years, and lays 1-6 clutches of between 70 and 110 eggs. The incubation period lasts 50 to 70
days.
Adult green turtles are the only truly herbivorous marine turtles. They feed mainly on
seagrasses or algae, mostly in the tropics and subtropics.
A current estimate of worldwide numbers of breeding female green turtles is 203,000. 1989
data suggest the main nesting beaches were in Queensland, Australia and in Indonesia.
Hawksbill Turtle (Eretmochelys imbricate)
The Hawksbill sea turtle is a small to medium-sized sea turtle and this species is characterised
by rough, serrated edges of the shell and a distinct beak-like mouth. The hawksbill shell is less
than three feet in length and is usually amber and reddish/ blackish-brown, with yellow streaks
or markings. Immature hawksbill turtles are usually black or brownish-black in colour. The adult
turtle can weigh up to 200 pounds.
The hawksbill appears to nest every 2 to 3 years and lays 60 to 200 eggs at a time. The hawksbill
often nests close to coral reefs, and can be encountered by snorkelers and scuba-divers at
localities where the turtle habitat is in a good condition. The nesting period for the Hawksbill is
July to November in Trinidad, and April to November in Tobago each year. The Hawksbill turtle
can be found in estuaries, bays, coral reefs and lagoons.
Hawksbill turtles are mainly carnivorous and use their narrow beaks to extract invertebrate
prey from crevices on the reef. Both sessile and mobile animals are eaten and hawksbills
appear to be opportunistic predators, although sponges normally constitute a major proportion
of their diet. Despite their protection under CITES, as well as under many national laws, there is
still a large amount of trade in hawksbills products, and this probably constitutes the major
threat to the species.
Hawksbills declined globally by over 80% during the last century. There are difficulties in
accurately assessing population size, but a recent estimate of adult nesting females of 8,000+
has been made. There are only 5 populations worldwide with more than 1,000 females nesting
annually.
Next week we will feature the Leatherback, Loggerhead and Olive Ridley turtles.
For more information visit www.ema.co.tt. If you have any comments or would like to
contribute to this column please respond to [email protected].
(Information sourced from Worldwildlife.org)