For Green Turtles, Some Good News (at Last)

Green Turtle

By Sophia Read

For The Bali Times

SEMINYAK ~ The green turtle (Chelonia mydas) is listed as endangered by the International Union for Conservation of Nature, but a new study suggests the outlook for them is not as bad as feared.

Conservationists studied the population of green turtles at Ascension Island, and discovered that it has increased by 232 percent since the 1970s. The green turtle population in Florida and Hawaii is also on the rise. Turtle protection measures seem to be working.

The study suggests that the listing “endangered” should perhaps only be applied to populations and species that are at serious risk of immediate extinction.

Green turtle populations are spread around the globe – Australia, the Caribbean, South Pacific, Africa, South America, even the Mediterranean. They have been badly affected by loss of habitat – as they will return to the beach they hatched on to lay their eggs some 30 years later – and if it has vanished, they do not breed. They have also suffered from being caught in trawler nets. The major factor in the endangered listing has been, however, the collection of eggs and adults from the nesting beaches.

After they hatch, the tiny turtles swim straight offshore, and do not return to coastal waters for several years – these are often referred to as “The Lost Years.” It’s only very recently that scientists analyzing the chemical accretions on their shells have determined that they spend these years on the surface of the ocean eating jellyfish and other creatures.

When they reach about 30cm in length, they return to coastal waters and become herbivores (unlike any other species of turtle), and feed mainly on seagrass and algae. Turtles are essential for the health of a seagrass meadow, as their grazing stimulates new growth. It’s this diet that gives them their name – the flesh of a green turtle is greenish, but they themselves are brown.

The listing of endangered has led to a battery of governments enacting legislation to protect their turtle – all the countries that have major nesting populations have moved to protect them. With legislation a great benefit, direct action has also helped. In the US, the Fisheries Office of Protected Resources has worked closely with the fishing industry, and developed “Turtle Exclusion Devices” (TEDS) which can be fitted to nets. They are a grid of iron bars, fitted to the mouth of the net, that simply prevents larger marine animals from entering. They have been adopted across the world.

The other significant factor in the population recovery has been the protection of habitats. All governments have moved to closely monitor and protect any known nesting beach – thus, human predation has greatly decreased. Turtle hatcheries have been set up worldwide, and hatchling-release programs greatly increase the percentage of hatchlings that actually reach the ocean, and therefore, hopefully, the percentage of those that survive to maturity.

The recovery of these populations is a welcome positive sign in these times of doom and disaster. With climate change now an accepted reality by all but the fanatic fringe, it’s easy to despair at the magnitude of the task we must achieve to halt the downward spiral of our ecosystem.

The green turtle has benefited by being considerably more attractive than many species that are more at threat. The world reacted relatively quickly to the threat, and concern was widespread. The popularity of turtles to divers and snorkellers may well have influenced the scale of the reaction by the respective governments. The population is also global, and they are a long-lived species, giving the species stability – it’s unlikely that one disaster could wipe out the species, as is unfortunately often the case.

Archey’s frog, for example, is found only at two sites, in the North Island of New Zealand – a disaster at one site would halve the global population in one fell swoop. The green turtle is vulnerable to fibropapilloma, a type of lesion, but it is unlikely that an outbreak would affect the entire global population. In contrast, the Chapa pygmy dormouse lives only in Vietnam – a disease introduced into that country would wipe out the entire species.

However, the recovery of the Green Turtles proves that we can stop species extinction; we just need to try.

The writer is sales manager of AquaMarine Diving – Bali.

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