Climate Change Watchmen

Contributed by Nature Seychelles

It's been a very exciting time for the Turtle monitoring team on Cousin Island and there is something of a celebratory mood at present. You see, nearly two months of waiting are over and slowly hundreds of nests will begin to release their prize: brand new baby hawksbill turtles.

“Alongside the hatchlings, we will also receive data from 30 nests through a pilot program looking at how cool or hot the nests are” says Jovanni Simeon, the Chief Warden of Cousin. The data will be retrieved from instruments called data loggers that were buried in the nest during laying.

"To date, we have maintained a long term rigorous monitoring programme for the Hawksbill on Cousin Island, which has helped in the conservation of this endangered species. Adding a new dimension with the temperature data loggers is expected to elevate this monitoring to new standards now being adopted elsewhere in the world. We have become climate change watchmen". Says Nirmal Shah, Nature Seychelles CEO.

Cousin Island is the most important nesting site in the western Indian Ocean for the critically endangered hawksbill turtle. They nest here, as in the rest of the Seychelles Islands, between August and February and intensive monitoring takes place during this period to collect as much information as possible to inform the conservation management of this species.

The turtle monitoring program on Cousin is based on regular beach patrols carried out around the island to intercept and collect data on as many turtles as possible. Tags applied to the turtles’ front flippers are used to identify individuals and to provide an estimate of the size of the nesting population. Other information such as the size of the turtle and tracks are also noted and the location of any nests are marked and recorded.

But now with the dangers of Global Warming all the conservation efforts may come to nought if we do not know what is going on and act in time. Why is this? Temperatures inside the turtle nests determine the sex ratio of hatchlings. Warmer temperatures produce more females and cooler temperatures give more males. With rising global temperatures, it is essential to understand the potential impacts of climate change on this thermally sensitive species. It is the temperature within the middle third of the approximately 60-day incubation period that determines the sex of the hatchlings.

Temperatures inside the nests determine the sex ratio of turtle hatchlings.

This is why during this season, data loggers were added to 30 nests to collect information on nest temperature. Nests are closely monitored around the time of hatching. The data logger is removed so data can be downloaded and used in estimating an approximate sex ratio of the hatchlings.

"As soon as we observe hatching, we prepare to download the data as well as take measurements from a sampling of the hatchlings. The total number of hatchlings is also recorded." Says Eric Blais Conservation Officer, who is working alongside volunteer, Mary Ledlie, who has given her time to this important project. Photos are taken to add to the information database on these animals.

Hawksbill hatchling being measured before release, photo Nature Seychelles

The new addition of climate change monitoring to the long term turtle management program on Cousin is expected to yield important results. Results that will help us to understand the impacts of climate change on wildlife and how we can react in appropriate ways to save our precious natural heritage.