Designated as environmentally sensitive species, they are all under threat
A leatherback hatchling heading to sea at Back Bay, Tobago, 2010. Photo by Ryan P. Mannette courtesy SpeSeas, used with permission.
This article was written by Michelle Cazabon-Mannette and originally published on Cari-Bois News. An edited version is republished here as part of a content-sharing agreement with Global Voices.
May 23 is World Turtle Day, marked annually to protect turtles and their disappearing habitats. In Trinidad and Tobago, the species most people are familiar with, thanks to their nesting habits and the country's conservation efforts, is the leatherback turtle, which visits the shores of the twin-island Caribbean nation each year from March to August. Less well known are four other sea turtle species, all hard-shelled: Hawksbill, Green, Loggerhead and Olive Ridley.
All five species share some common characteristics. They all spend the majority of their long lives at sea, travelling great distances, with the females returning to beaches near their birthplace to lay large numbers of eggs. All hard-shelled sea turtles have bony plates called scutes that make up their shell, the pattern of which, in addition to the number of prefrontal scales between the eyes, is key to determining the species.
They are all also under threat, and have been designated as environmentally sensitive species. Local penalties for harming these turtles are 100,000 Trinidad and Tobago dollars (nearly 15,000 United States dollars) and imprisonment for two years.
Leatherback (Dermochelys coriacea), Vulnerable (IUCN)
Early morning leatherback at Grande Riviere, along Trinidad's east coast, 2018. Photo by Ryan P. Mannette courtesy SpeSeas, used with permission.
The largest of the sea turtles, leatherbacks spend a significant portion of their lives in the vast open ocean, travelling thousands of kilometres. They can be found in all tropical and subtropical oceans, with a range that extends into the much cooler Arctic Circle.
What sets leatherbacks apart from other sea turtles is their soft, leathery shell, which enables them to dive deeper than any other species of sea turtle. Their main diet consists of soft-bodied animals that drift throughout the water column, such as jellyfish.
For nesting season, they favour warmer climates. Trinidad and Tobago, located at the southern end of the Caribbean archipelago, is home to one of the largest populations of nesting leatherbacks in the world; as such, the country has played an important role in global conservation efforts.
While global populations are considered to be vulnerable, due to recent declines, the regional subpopulation is currently classified as endangered—a more alarming designation—by the International Union for Conservation of Nature (IUCN).
The primary threat to leatherbacks, both locally and globally, is bycatch of the species in fisheries.
Hawksbill (Eretmochelys imbricata), Critically Endangered (IUCN)
A juvenile hawksbill resting on the reef at Castara, Tobago, 2012. Photo by Ryan P. Mannette, courtesy SpeSeas, used with permission.
Hawksbills are the next most common turtle using Trinidad and Tobago as a nesting ground. Being a small, agile species, their nesting activity is scattered across many beaches, including small bays protected by rocks or reefs. Mature females make breeding migrations between foraging and nesting grounds on the scale of hundreds to thousands of kilometres.
Juvenile hawksbills can be found in local waters year-round, in coral reefs, underwater cliff walls and hard bottom habitats, where they feed primarily on sponges. Their unique diet helps maintain the diversity and health of coral reefs. Distinct from the nesting population, they originate from a variety of other islands, including as far away as Cuba and Puerto Rico.
Hawksbills can be recognised by their four lateral scutes, two pairs of prefrontal scales, and narrow, pointed beak. The scutes on their shell overlap like shingles on a roof, resulting in the serrated appearance of the shell, which appears more prominently in juveniles.
Hawksbills are distributed throughout the tropics and, to a lesser extent, the subtropics. Turtles born on the shores of Trinidad and Tobago tend to migrate widely across the Caribbean region, with females returning to nest.
Sadly, hawksbills have been harvested for their beautiful “tortoiseshell,” which in the past was used to make jewellery and other decorative items. IUCN lists them as critically endangered.
Green (Chelonia mydas), Endangered (IUCN)
A juvenile green turtle swimming offshore Curaçao, 2017. Photo by Ryan P. Mannette, courtesy SpeSeas, used with permission.
Uncommon to find in Trinidad and Tobago, green turtles are the largest of the hard-shelled turtles. Just like the hawksbill, however, juvenile greens do live offshore year-round. They are a herbivorous species, feeding primarily on seagrass and algae, and typically live in seagrass beds and coral reefs, where algae may be present.
They are occasionally spotted around the rocky coastlines of Trinidad's north and east coasts, and their grazing activity plays an important role in maintaining the health of seagrass beds and coral reefs. They are easily distinguished from hawksbills by their blunt beak and are the only species with one pair of prefrontal scales between their eyes.
While the meat from the green turtle has generally been the most sought-after worldwide, both hawksbills and greens continue to be threatened locally by poachers, either on beaches or at sea. IUCN lists them as endangered.
Loggerhead (Caretta caretta), Vulnerable (IUCN)
A sub-adult loggerhead that was stranded on Manzanilla beach along Trinidad's east coast; it was successfully rehabilitated and released in 2017. Photo by Ryan P. Mannette courtesy SpeSeas, used with permission.
Loggerheads are rare in Trinidad and Tobago, but a number of sightings have been confirmed over the last 12 years, off Trinidad's east, south, and western coasts, as well as around Tobago.
In 2017, one loggerhead that was stranded on the east coast was successfully rehabilitated and subsequently released with a satellite tag, which showed that the turtle spent some time exploring the Gulf of Paria after being released.
Loggerheads are distinguishable from other species by their large heads and the five lateral scutes on their shell, though hatchlings may easily be mistaken for hawksbills if you don’t pay attention to the scute pattern.
Loggerheads like muddy, hard-bottom habitats, where they feed on a variety of animals, including shellfish, which they crush with their large heads and strong jaws. They nest along shorelines in tropical and temperate zones, and frequent all tropical and temperate ocean basins, with Florida boasting the largest nesting population of loggerheads in the world. IUCN lists them as vulnerable.
Olive Ridley (Lepidochelys olivacea), Vulnerable (IUCN)
An injured Olive Ridley that stranded on Lambeau beach in Tobago, 2007. Photo by Ryan P. Mannette courtesy SpeSeas, used with permission.
The smallest of the sea turtles found locally, sightings of Olive Ridleys are rare, but they do happen. Their varied diet, which can include crabs, snails, barnacles, algae, fish, jellyfish and other soft-bodied animals, means that they feed in soft-bottom coastal habitats, as well as at the surface of the open sea.
The species usually has six or more lateral scutes, making them distinct from the other species found locally. In some parts of the world, Olive Ridleys exhibit a unique nesting behaviour called an “arribada,” whereby thousands of nesting females coordinate and nest on a single stretch of beach over the period of a few days. During the nesting season, the entire group remains close to their nesting beach, but this behaviour has not been recorded in Trinidad and Tobago, which sees only the occasional, solitary nesting turtle. IUCN lists Olive Ridley as vulnerable.
These once-abundant sea turtles play important roles in maintaining healthy marine ecosystems, yet they have been harvested for their meat, eggs, shells and other products, including intensive harvesting by the region's European colonisers in the 17th and 18th centuries, which significantly depleted the populations.
Locally, sea turtles generate significant revenues from eco-tourism activities that include guided tours to nesting beaches and scuba diving. Despite this, the species continues to face numerous threats, including continued attempts at harvesting, bycatch, habitat loss, climate change and plastic pollution.
If you want to contribute to learning more about sea turtles in Trinidad and Tobago, the marine advocacy website SpeSeas encourages netizens to become citizen scientists by filing reports on turtle encounters.
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