marine turtle info

7/31/2019 Marine Turtle Info

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the Leatherback(Dermochelys coriacea)

Listed under CITES Appendix 1

The leatherback is the largest species, reaching a shell length of about sixfeet and a weight of 1000 pounds or more. The shell is unique: instead of

being covered with large, horny plates or "scutes," it has an undivided,

smooth, black or white-spotted surface and is raised into seven strongridges that run almost the entire length. The skin covering the shell is

paper-thin, but just below the surface is a layer composed of thousands ofsmall bones that form a mosaic, and below this is a layer of tough, oily

cartilage about two inches think. The ridges probably help the otherwise

flexible shell keep its shape, and also may function in streamlining. Theleatherback is a great diver, descending rapidly to a thousand feet or more

(although Guyanese waters are not this deep!), and moves enormousdistances across or around the North Atlantic between nesting season.

Traditional tagging in Surinam has shown that the turtles may reach New

England or even eastern Canada within a few months, and one taggedleatherback swam to Ghana in West Africa! Satellite tracking in French

Guiana has shown the routes (mainly towards the northwest) that turtlesfollow after their nesting season ends. Leatherbacks can maintain activity

even in very cold water, and the usual diet is jellyfish, which they seize

with their sharp-edged jaws. In Guyana, the leatherback is traditionallycalled "matamata," and nesting occurs on beaches of the North-West, from

Waini Point to Tiger Island. Many were slaughtered on the beaches beforethe protection patrols started around 1988, but the numbers currently are

relatively strong, and the 2000 season was the best year on record, by far.

the Green Turtle(Chelonia mydas)Listed under CITES Appendix 1

The green turtle, known traditionally in Guyana as "bettia," is the largest of

the so-called hard-shelled species, reaching a shell length of about fourfeet and a weight of about 600 pounds. The species is easily identified by

its relatively small head with a short, rounded snout, and by its smoothshell with four large scutes along each side. In color, the green turtle is

very variable (it is rarely actually green, a name that relates to the color of

the fat inside!). Hatchlings are almost black above and pure white below,but they soon become streaked with brown, and old adults sometimes

have a spotted pattern, or become uniformly grayish. The green turtlesnesting in Guyana are among the biggest in the world, and may be twice

the weight of the Caribbean green turtles that nest in Costa Rica. As an

adult this species is a grazer, some populations concentrating upon seagrasses of various species, while others eat seaweeds, technically known

as macroalgae. Because the food plants most typically grow in calmwaters, while the best nesting beaches have strong wave action and may

be a long way off, the turtles are obliged to migrate many hundreds ofmiles between good feeding grounds and good (and safe!) nesting


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grounds. Nesting occurs in Northwestern Guyana and in eastern Surinam,and the best regional feeding grounds are in eastern Brazil. The Surinam

population, which has not been exploited for meat for a great many years,remains strong, but in Guyana many years of slaughter have brought the

nesting population down to a very low level.

the Green Turtle(Chelonia mydas)Listed under CITES Appendix 1

The green turtle, known traditionally in Guyana as "bettia," is thelargest of the so-called hard-shelled species, reaching a shell lengthof about four feet and a weight of about 600 pounds. The species iseasily identified by its relatively small head with a short, roundedsnout, and by its smooth shell with four large scutes along each side.

In color, the green turtle is very variable (it is rarely actually green,a name that relates to the color of the fat inside!). Hatchlings arealmost black above and pure white below, but they soon becomestreaked with brown, and old adults sometimes have a spottedpattern, or become uniformly grayish. The green turtles nesting inGuyana are among the biggest in the world, and may be twice theweight of the Caribbean green turtles that nest in Costa Rica. As anadult this species is a grazer, some populations concentrating uponsea grasses of various species, while others eat seaweeds,technically known as macroalgae. Because the food plants mosttypically grow in calm waters, while the best nesting beaches havestrong wave action and may be a long way off, the turtles areobliged to migrate many hundreds of miles between good feedinggrounds and good (and safe!) nesting grounds. Nesting occurs inNorthwestern Guyana and in eastern Surinam, and the best regionalfeeding grounds are in eastern Brazil. The Surinam population, whichhas not been exploited for meat for a great many years, remainsstrong, but in Guyana many years of slaughter have brought thenesting population down to a very low level.

the Hawksbill(Eretmochelys imbricata)


The hawksbill, sometimes known by the Spanish name "carey," is smaller

than the green turtle, reaching a shell length of about three feet and aweight of about 160 pounds. Instead of a short, rounded snout, it has a

narrow head with a pointed, protruding beak. Why this turtle is called

"hawksbill" is unclear, since a hawk has a downcurved bill while the turtlehas a straight one, but the beak is certainly bird-like. The hawksbill is


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widely distributed in the tropics, often living on coral reefs where itprimarily eats sponges, and populations have been reduced in many areas

for the thick, decorative shell plates, known as "genuine tortoiseshell,"which (before the international ban) fetched a high price on international

jewelry markets. It is somewhat of a mystery why the hawksbill nests onthe muddy shores of Guyana, and indeed there are only small numbers in

the country, with almost none in Surinam and French Guiana. But the onesthat do nest in Guyana are among the biggest in the world, and everynesting recorded is somewhat of a "special event."

the Olive-Ridley(Lepidochelys olivacea)


The olive ridley is the smallest of the sea turtles, adult females being about

26 inches long and weighing 80-100 pounds. The shell is short and almostcircular, the overall color is yellowish-olive (although hatchlings and

juveniles are grey), the head is triangular and bluntly pointed when seenfrom above, and there are at least five large plates along each side of the

shell, sometimes as many as nine. This is a tropical species, huge numbers

participating in mass-nesting events (called "arribadas") on a few, widely-flung beaches in Mexico, Costa Rica, and India. It was unknown in the

western Atlantic until Peter Pritchard discovered them nesting inNorthwestern Guyana in 1964, and around the same time Joop Schulz

discovered nesting in eastern Surinam, where small "arribadas" of up to

500 turtles occurred. Today the West Atlantic populations are seemingly

collapsing, and seasons go by without a single nest being recorded inGuyana, and just a few in Surinam, although in eastern French Guiana,near Cayenne, the nesting numbers are growing. The populations may

thus have either shifted or collapsed - or probably both. They are forced to

shift when mud flats build up in front of the beaches, as happened atEilanti Beach in eastern Surinam; and the populations have been hard

pressed by drowning of large numbers in shrimp trawls. Tagging byPritchard in Surinam has demonstrated that many individuals migrate to

Venezuelan and Trinidad waters after nesting two or three times in

Surinam, and the captured turtles reported by trawlermen have provided agreat deal of information about the at-sea habitats of the population

the Loggerhead(Caretta caretta)

The loggerhead turtle has never been found nesting in Guyana, but youngspecimens are occasionally washed up, dead or alive, along the northwest

coast. These turtles primarily nest in the eastern United States (especiallyFlorida) although there are also southern nesting colonies in southern

Brazil. After hatching in Florida, the young turtles embark upon a largely

passive circuit of the North Atlantic Ocean, carried northeast by the Gulf


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Stream and passing by the Azores, Canaries, Madeira, etc, where theymay reside for a time, feeding and growing. Eventually they are picked up

by the Equatorial Current and brought back to the Americas, and this iswhen they may be caught as they pass the Guianas. Loggerheads are

somewhat like ridleys in appearance, but are longer and narrower, withenormous heads, and the shell, head, and limbs are reddish-brown rather

than grey or olive. The large scutes along each side of the shell are almostalways five in number. The jaws are extremely strong and are adapted forfeeding upon very hard-shelled crabs, conchs, and other generally bottom-

living marine species.

marine turtle info

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