Saving Paradise

Category: Cousin Island, Turtles | Date: Nov 10 2009 | By: savingparadise

It is that time of the year again and hawksbill turtles are making their annual pilgrimage to our shores to nest. The hawksbill breeds throughout Seychelles, peaking between mid-October and mid-January.  On Cousin Island, Conservation Officer Eric Blais reported an early appearance on August 8. Appearances are starting to pick up now and more turtles will arrive in November, December and January.

As numbers peak, so will monitoring. On a short visit to Cousin yesterday (9 Nov 2009), I took part in an afternoon monitoring exercise with Eric, David (Science Coordinator for Nature Seychelles), Mary (a volunteer helping with the turtle work) and Claire (from Kelonia) to see just what this means.

Cousin Island has one of the longest running monitoring programmes - started in 1972 - forming a core part of the wardens and volunteers work programs. Appearance dates and locations have to be recorded, with nesting beaches being patrolled several times a day. Metal tags with unique identification code, attached to the front flippers of each nesting turtle encountered help identify individual females returning to the beach each season.

Turtle emergences are recorded under four categories of behaviour: 1) “LAID” during which eggs were laid after digging one or more nests; 2) “Did Not Lay (DNL)” during which one or more nests were dug but no eggs laid; 3) “Half Moon (HM)”emergences during which digging did not occur although no disturbance factors were apparent; and 4) “Emergence Stopped by Obstacle (ESBO)” during which no digging occurred because the female was discouraged by obstacles on the beach.

After a short walk, we came across a female who had just begun to dig her pit. As I took covert pictures of her, my colleagues went about taking their data and doing their tagging. To my utter surprise Mary put her hand into the pit and with a counter in the other, began to tally the eggs as they came out.

A female turtle crawls out of the sea and using her front flippers drags herself up to the beach to a suitable nest site. There, she digs a pit with her front flippers and then excavates a vertical egg chamber with her hind flippers in which she lays her eggs. Eggs can be as many as 250. Mary counted 210 eggs for this one! Afterwards, the turtle used her hind legs to cover up the nest with sand and returned to sea.

It will take close to sixty days for the eggs to hatch and two or more days for the baby turtles to get to the surface. The babies will emerge as a group and - usually at or after dusk - head towards the sea attracted by the reflection of the moon on the water. But they face a number of challenges. Once hatched, babies are a favorite food for ghost crabs, birds and fish. Baby turtles could also be affected by beach lighting, which can cause them to head inland rather than out to sea. On Cousin, lights are of low wattage and screened from all nesting beaches.

As I left Cousin, I reflected on the work ahead for these hardworking people. Things will certainly get very busy soon. But thankfully, the collection of data will be increasingly efficient due to new technology and data analysis techniques that are being introduced.

Tags: Cousin Island, hawksbill turtle, monitoring