Turtles and tourism

Back into the marine world once more, with a story this week that has provided the first robust evidence that sea turtles are more successful at producing young when females lay their eggs on beaches that are untouched by human hand.

That's according to David Pike from the University of Sydney in Australia who published his study this week in the journal Biology Letters.

They may spend the majority of their lives in the ocean, but female sea turtles are tied to the land and have to haul themselves out on beaches to lay their eggs.

What Pike did was to hunt through hundreds of other studies published by people who have gone out and counted how many turtle eggs hatch on different types of beach - both those were people are present, with coastal developments like hotels and resorts, and beaches where there is no permanent human presence.

And what he found may not come as much of a surprise: for both the magnificent loggerhead turtles, and green turtles, on average around 12 to 16% more eggs hatched on undisturbed beaches compared to those on beaches with human developments on them.

That may not sound like a lot, but this is likely to be an important difference for turtles that face a host of different threats to their survival, including being accidentally caught at sea in trawling nets and because turtles often mistake plastic bags for one of their favourite food: jellyfish.

It is not clear exactly why the hatching success rate is so much lower on developed beaches, but it is likely to be a combination of factors including trampling and physical disturbance by people and various forms of pollution.

This study has shown how crucial it is to protect nesting beaches that are currently not disturbed by coastal developments because there are the areas where many turtles are being born, and it is the young turtles that will determine the future of these wonderful species.