Sea Turtle Awareness MonthKnow your ESS turtles!
The Leatherback, Loggerhead and Olive Ridley turtles
Last week we featured we featured the characteristics of two of the turtle species designated
as Environmentally Sensitive Species (ESS) by the EMA- the Green and Hawksbill turtles. This
week we will continue with the characteristics of the Leatherback, Loggerhead and Olive Ridley
turtles.
Leatherback turtle (Dermochelys coriacea)
This is the most commonly known species of turtle in Trinidad and Tobago. The Leatherback is
quite different in shape and physiology to other marine turtles. This species has a soft, leathery
shell with seven longitudinal ridges or keels. The shell of the adult Leatherback turtles is black in
colour with white spots and interrupted white lines on the keels. The head is black with large
white markings and a pink spot on the top of the head.
Leatherbacks are the largest turtles on earth and the weight of adults generally exceed 1100
pounds. Their nesting period is February to August each year and can be found in beaches such
as Matura, Grand Riviere and Manzanilla, in Trinidad, and Black Rock, Turtle Beach and
Englishman's Bay in Tobago.
Female leatherbacks may lay 4 to 5 times per season, each time depositing 60 to 120 eggs.
Leatherbacks appear to nest once every two or three years with an incubation period of
approximately 60 days.
The large size of leatherbacks is all the more remarkable given their low energy, low protein
diet of soft-bodied creatures such as jellyfish, squid and tunicates ("jelly fish-like" marine
invertebrates).
Loggerhead Turtle (Caretta caretta)
This species is the rarest marine turtle found in Trinidad. A loggerhead nesting event was
recorded in Tobago in the mid-1990s as such nesting activity has been a rarely recorded event.
The head and upper shell range from a yellow-orange to a reddish-brown, while the underside
is typically pale yellow. The turtle's neck and sides are brown on the top and yellow on the sides
and bottom, and has a distinct patchwork of hexagonal- rings on its back.
The adults generally exceed 400 pounds and average 250 pounds in weight. The age of sexual
maturity has been estimated at between 10 and 30 years but studies in Australia indicate that it
may be between 34 and 37 years.
Females nest an average of 3 to 5 times per season, and between 40 and 190 eggs are laid per
clutch. Data from studies in the USA suggests that nesting takes place about every 2 years. A
recent estimate of the numbers of nesting female loggerheads is more than 60,000.
In terms of diet, Loggerheads are carnivorous eating bottom dwelling molluscs (conches,
clams), crabs, urchins and sponges, as well as free swimming jellyfish and seemingly
impenetrable prey such as the queen conch.
Olive Ridley (Lepidochelys olivacea)
The Olive Ridley species is one of the smallest sea turtles in the world, and is named for the
colour of its shell. This species has an olive or greenish-white, round shell and a yellowish-white
plastron. Their beaks are usually horny and serrated.
The Olive Ridley generally weighs about 100 pounds and has an average length of 70 cm. Their
nesting period is unknown in Trinidad and Tobago but the species is known to exist in our
waters. Most individuals of this species nest at river mouths, estuaries and prefer low saline
conditions.
After reaching sexual maturity when they are about 12 years old, thousands of females emerge
from the sea and nest simultaneously over a period of 2 to 3 days. The olive ridley often
chooses small, narrow beaches and their nests may be so closely packed that subsequent waves
of females often dig up other nests in efforts to lay their own eggs.
The Olive Ridley feeds essentially on crabs and shrimps, but also jellyfish, small invertebrates,
tunicates, small invertebrates and fish eggs. Individuals have been captured in prawn trawls at
depths of 80 to 110m, and are therefore considered capable of foraging at these depths.
The Olive Ridley is a threatened species in Central America as the illegal harvest of its eggs
continues. There is also high mortality of adults due to coastal fisheries that do not yet use
Turtle Excluder Devices (TEDs) in their nets.
Each of the above ESS is protected by law and illegal activities such the taking, removing,
harming, injuring, hunting, selling or killing of the turtles and possession of or trade in any
specimen of the living animal and its parts, eggs and products are strictly prohibited!
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].