Eco-Corner: Sea Turtles and their Natural Habitats

Beach and sand dune at Cove Bay

These habitats also act as nursery areas for hatchlings (baby sea turtles). On land, the beaches and sand dunes are used by female sea turtles as nesting areas. Female sea turtles dig their nests deep into the sand where their eggs will be protected and incubated.

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Seagrass bed at Forest Bay

Some of us have been lucky enough to have seen sea turtles up close, either in the water or nesting onshore. If you look closely enough, in Island Harbour where a rich seagrass bed grows, you can sometimes see green sea turtles poke their heads above the water’s surface as they fill their lungs with air before ducking back under waves and into the marine environment where they are most at ease. While we may think that there are many sea turtles in Anguilla’s and the world’s waters, sea turtle populations are in fact under extreme stress – so much so that the World Conservation Union (the International Union for the Conservation of Nature) has listed them as at least endangered. For the sea turtle species that are found in Anguilla’s waters – the Leatherback, Hawksbill, and green – the former two are listed as critically endangered while the latter is considered endangered. There are stories, however, from the time of Columbus, of boats being surrounded by hundreds of sea turtles at any one time – the Caribbean Sea was teeming with these creatures.

Porites colony at Sandy Island

For populations to have declined so dramatically that their very existence on this planet is threatened is disturbing to say the least.

Sea turtle populations have been directly and negatively impacted by the over-harvesting of adults and their eggs and this has undeniably led to a significant decline in their numbers. At the same time, however, loss of habitat has also contributed to their endangered status and, to an extent, limited their populations’ ability to recover.

A Closer Look at the Critical Ecosystems

The Importance of Coral Reefs
Coral reefs are living and growing underwater structures that have taken thousands of years to form. Made up of small, individual, simple animals living in a symbiotic relationship with zooxanthallae (single-celled algae), coral reefs are extremely sensitive to the temperature, salinity, and clarity of the water in which they live, as well as to the amount of nutrients in it. Too much or too little of any of these things and coral reefs won’t be healthy and their ability to survive could even be compromised. Maintaining their health is essential: coral reefs provide homes and nursery grounds for a wide range of commercial and non-commercial fish species; provide sand for beaches; act as barriers against wave action; produce materials of medicinal value; and directly and indirectly support fisheries and tourism industries. For sea turtles, coral reefs are foraging grounds and protective habitat.

As sensitive and fragile environments, coral reefs are being damaged at an alarming rate – in Anguilla and around the world. Some of the major negative impacts on coral reefs are from:
• Water pollution, including the land-based and water-based dumping of high-nutrient sewage and garbage into the nearshore environment.
• Sedimentation, where particles of disturbed sand and soil from erosion, inappropriate coastal construction, or coastal dredging blanket the reefs and prevent them from growing, sometimes suffocating and killing them.
• Careless nearshore usage, including the dropping of anchors on reef structures, swimmers standing on them, physically removing them for souvenirs or jewellery, and damage caused by spearguns when the gun accidentally hits corals if it misses its intended target.
• Coral bleaching, caused by an increase in sea temperature that kills the coral animals and makes the reef more susceptible to lethal diseases.

The Importance of Seagrass Beds
Seagrass are types of plants that have evolved from those found on land. They are specialised to live completely submerged in water but they still have leaves, roots, flowers, and seeds. They are able to make their own food through a process called photosynthesis during which light energy is used to convert carbon dioxide and water into chemical energy.

Similar to coral reefs, seagrass beds are also sensitive to changes in the waters that surround them – so much so that they are considered to be important indicators of the general health of coastal ecosystems. Beyond this, seagrass beds provide food, shelter, and nursery areas for commercial and recreational fish species and many types of invertebrates as well as for sea turtles. The extensive network of seagrass roots that run under the sea bottom prevents predators from digging too deep and from preying on organisms that bury themselves in the sandy ground. The roots also prevent erosion of the sea bottom by keeping the sand compact and in place.

Similar to coral reefs, however, seagrass beds are also being threatened, with the most serious threats being:

• Water pollution.
• Sedimentation.
• Careless nearshore usage, including the dragging of anchors through seagrass beds which in turn uproots the grass and the scraping of propellers through the grass which can scar them significantly.

Importance of Beaches and Sand Dunes
Anguilla’s beaches and sand dunes were formed hundreds of thousands of years ago and are coral- and limestone-based. That is, they were formed through the breaking down of coral reefs and calcium-based algae into tiny particles that were then deposited by wave action onto Anguilla’s nearby shores.

Both beaches and sand dunes are dynamic: they are structures that are constantly changing in shape and size, depending on the amount of sand deposition (which increases their size) and erosion (which decreases their size).

Beaches and sand dunes are an important part of the interconnected coastal system: they act as natural buffers against eroding wave action; function as filters of sediment and bacteria found in the water that passes through them; provide nesting, feeding, and resting habitat for many different species of birds, invertebrates, and reptiles (including the endangered sea turtles); and are used for recreation by more people (residents and tourists alike) than any other habitat found on the island.

Beaches and sand dunes are especially sensitive to human-based stressors, including:
• Unsustainable/Inappropriate coastal development, especially when buildings are not setback from the coastal vegetation line (which tends to lead to beach erosion and when outdoor lighting takes no regard for impacts on sea turtle nesting behaviour (lighting often disorients nesting sea turtles and their hatchlings so that they head further inland instead of towards the sea, and can therefore lead to increased incidences of death).
• Sand mining, where sand is physically (and illegally) removed from the beach, leading to chronic beach and sand dune erosion and a net loss of critical habitat.

Ecosystem Conservation
Anguilla’s coastal ecosystems – its coral reefs, seagrass beds, beaches, and sand dunes – work together to help maintain a delicate balance that keeps Anguilla’s coastal waters and shoreline clean, stocked with fish, lined with white sand, and protected from excessive and destructive wave action. For sea turtles, whose populations have declined dramatically, urgent action is required to protect the habitats on which they depend. While Anguilla’s moratorium on harvesting these marine reptiles and their eggs speaks volumes of the government’s, and our people’s, commitment to species conservation, equal concern and attention on the sustainable use and conservation of the island’s coastal ecosystems is also needed. While it may take more time and effort to develop and implement a national coastal conservation plan, it will undoubtedly be a wise investment for the future of this island, its people, and its sea turtles.

For more information about the ASCG, its activities, or what you can do to help protect Anguilla’s sea turtles, please contact Ms Janeczka Richardson, ASCG Coordinator, at axascg@hotmail.comor at 497 5297 / 729 9443.
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