Sea turtles

During my Bachelor studies I went to Costa Rica to protect sea turtle eggs and to study the effect global warming has on the development of these eggs!

In Costa Rica the 'nesting season' falls between July and October. That is when female sea turtles migrate to beaches at night to lay eggs in the sand. I patrolled the beach of 'Reserva Playa Tortuga' for weeks in the dark to find the eggs before the poachers would find them, who would trade or consume them. My colleagues and I, however, took the eggs to a safe hatchery. Later, we would release the freshly hatched baby sea turtles back to the sea.

The species that nested at the location where I stayed is the olive ridley (Lepidochelys olivacea). That is the smallest of the seven existing sea turtle species. When we came across an olive ridley, we had to measure it and help out with the nest. Sometimes we had to hold them back briefly in case we had not yet recorded all the data, but the sea turtle decided it was time to return to the water. This sounds easier than it is! They may be relatively small, but still they can be surprisingly strong!

All sea turtle species are endangered, for instance by illegal poaching and overfishing. But in Costa Rica I focused on a less 'visible' issue. I investigated the temperature of the nests. Why? Because sex determination in sea turtles depends on environmental temperature. As the earth is warming, the sex ratio is shifting: more and more females, and fewer males, are being born. This can of course become a problem once the ratio will shift too much...