Hundreds of extinct snails released into the wild

Hundreds of extremely rare Partula snails bred at the Royal Zoological Society of Scotland’s (RZSS) Edinburgh Zoo have been flown more than 15,000km to be reintroduced to their French Polynesian home. The wildlife conservation charity has been helping to restore wild populations of the species since 1984.

Jo Elliot, curator at RZSS, said: “It is extremely exciting to be able to send some of our Partula snails, which we have been breeding for years, to be reintroduced directly back into their native habitat. We are extremely proud to be part of this vital collaborative breeding project, which is giving this incredible species a significant boost.

“Our success within the Partula snail programme is owed to the teams who began the work here at Edinburgh Zoo many years ago and to those who now form the wider project partnership, working to ensure this initiative goes from strength to strength. This is a really wonderful conservation success story and further demonstrates the critical role zoos can play in species recovery.”

Now on their way back from the brink of extinction thanks to the dedicated work of conservation zoos and the French Polynesian Government’s Direction de l'environnement, Partula snails were previously under imminent extinction threat in the 1980s and early 1990s after the predatory ‘rosy wolfsnail’ was introduced from Florida to rid the islands of a previously-introduced alien species - the giant African land snail. Unfortunately, the rapacious predator devoured the tiny native snails instead.

Not only did this harm the islands’ fragile forest ecosystem, as the snails are important vegetation recyclers, but the snails have also been a huge loss for Polynesian culture, as the snail shells were sustainably used in cultural artefacts.  

The last few surviving individuals of several Partula species were rescued in the early 1990s by RZSS and ZSL, in order to begin the international conservation breeding programme – a collaboration between 15 zoos which care for 15 species and sub-species, the majority of which are classed as extinct-in-the-wild. Combined with others already being studied at universities around the world, it was these individuals that formed the source group to begin re-populating the Islands.

Since 2015, conservationists have reintroduced more than 24,000 Partula snails onto French Polynesian islands, with each year’s release painted with a dot of a different coloured glow-in-the-dark animal-friendly ‘snail varnish’ - so that their individual progress can be monitored with the help of a UV torch light. Snails released earlier in the year sport an orange dot while the most recent cohort are blue.

During recent surveys of the release sites on the French Polynesian island of Moorea, unmarked juvenile snails were found as well as orange-marked snails released by RZSS senior keeper Craig Close earlier this year that had grown into adults. This is incredible news for the species and demonstrates that the species is potentially breeding successfully in the wild.

Jo added, “We were thrilled to learn that the reintroductions have gone well so far and that snails from earlier releases have been found within the habitat continuing to thrive. It’s a great result for Partula snails and shows that all some species need to flourish is a helping hand.”