Threatened geckos returned to the wild five years after being rescued from oil spill in Mauritius

In a major step to prevent another extinction on Mauritius, Durrell Wildlife Conservation Trust has returned 57 eggs of the endangered lesser night gecko to the wild on the remote islet of Ilot Vacoas. The move is part of a long-term effort to protect the species, whose survival was put at serious risk by the 2020 MV Wakashio oil spill.

The lesser night gecko, found only on four islets, is now listed as Vulnerable on the IUCN Red List. Invasive predators, fire, extreme weather and habitat loss all threaten the species. The situation worsened significantly in 2020 when the MV Wakashio spilled around 1,000 tonnes of toxic oil into the surrounding marine and coastal environment.

In response, Durrell and its partners launched an emergency rescue, relocating 66 reptiles to Jersey Zoo, including 30 lesser night geckos. Supported by the Jean Boulle Group, the animals were transferred to form a new ‘assurance population’ under expert care.

Matt Goetz, Interim Director of Zoo Operations at Jersey Zoo and Curator of Herpetology, who managed the team that looked after the geckos at the zoo said: "Our team had to replicate the natural habitat for the geckos and provide highly specialised care. Every individual survived and the geckos have since bred very successfully."

DNA analysis of wild geckos on Ilot Vacoas, carried out by Cardiff University using samples from 2021 and 2022, showed that the oil spill had altered the genetic structure of the population. This reduced the geckos’ ability to adapt to future threats and increased the risk of extinction. By contrast, the geckos in Jersey Zoo retained the pre-spill genetic diversity, providing a vital opportunity to restore what had been lost.

From mid-2023, Durrell’s Herpetology team adjusted lighting and enclosure conditions at Jersey Zoo to replicate the Mauritian climate and encourage breeding at the right time of year and by December 2024, 57 eggs were prepared for transfer to Mauritius.

In January 2025, the eggs were returned to Ilot Vacoas in partnership with the Mauritian Wildlife Foundation and the National Parks and Conservation Service. Custom-built egg release units were used to protect them from predators and weather. Of the 57 eggs, 88% successfully hatched. Durrell now has plans to replicate this translocation on an annual basis at a larger scale, to further safeguard the future of this species.

Dr Nik Cole, Island Restoration Manager at Durrell who helped co-ordinate the rescue effort and was part of the team who undertook this successful translocation commented: “This whole project from start to finish has provided a much-needed lifeline for this precious species. Transporting these eggs halfway across the world and having such a high hatching rate is no mean feat. For our first repatriation effort, we couldn’t have asked for better results, it’s truly phenomenal”.

Becky Brewer, CEO of Durrell Wildlife Conservation Trust, said: "The successful return of these gecko eggs to the wild is a hopeful moment in a story that could have ended very differently. It shows what’s possible when science, commitment and collaboration come together to protect life on the edge."

The initiative is part of the Mauritius Island Restoration Programme, a partnership between Durrell, the Mauritian Wildlife Foundation and the Government of Mauritius National Parks and Conservation Service, with support from the Government’s Forestry Service.