Over 1,300 Tiny Captive-Bred Snails Released on Uninhabited Island

Conservation efforts for endangered animal species sometimes involve breeding them in captivity so that they can be released into their natural habitat. Recently, Siberian tigers found orphaned grew up in semi-captivity before being successfully released across the Russian-Chinese border.

This time, they are tiny snails that have bred safely in zoos in order to reach their habitat. Biologists actually released 1,329 pea-sized snails on the island of Bugio located in the Desertas Islands archipelago.

Invasive predators almost caused these tiny snails to become extinct

Snails are native to the Desertas Islands off the coast of Madeira. They were previously thought to be extinct. Their population has declined sharply following the introduction of invasive predators such as rats, mice and goats. Neither species had been observed for a century.

Fortunately, conservation expeditions conducted between 2012 and 2017 confirmed that these tiny snails were still very much alive. However, there were only 200 surviving individuals left on Deserta Grande Island. Located southeast of Madeira, this mountainous, windswept island is uninhabited.

These 200 snails could well be the last of their respective species. Biologists therefore collected them in order to breed them in captivity. They were sent to zoos in France and the United Kingdom.

The released snails were marked with a blue dot on their shell

Chester Zoo near Liverpool has provided them with a suitable habitat in a converted transport container. Miniature aquariums with the right food, vegetation and conditions have been prepared especially for them. 60 of these tiny snails have taken up residence there.

These gastropods thrive at Chester Zoo. The biologists therefore decided to release 1,329 snails on their island of origin. These are the offspring of the 60 snails that arrived at the zoo.

Before being released into their natural environment, the 1,329 snails were all marked. Small identification dots were made on their shells with non-toxic pens and nail polish.

“It’s color coded. This will allow us to spot them and track where they disperse, how they grow, how many survive and how they adapt to their new environment,” explains Dinarte Teixeira, conservation biologist at the Institute for Nature Conservation and forests of Madeira.

Snails are essential for decomposing organic matter

In order to protect them from invasive species, the snails were released on the small island of Bugio. This has been prohibited to humans since 1990 in order to preserve its ecosystem. Invasive species have also been eradicated there. So the snails no longer have to worry about rats, mice and goats.

They will still serve as a food source for the island's native predators. “These snails are such an important part of the natural habitat of these islands. As well as being a food source for other native species, snails break down organic matter and provide nutrients to the soil,” says Heather Prince of Chester Zoo.

More tiny snails could be released next spring

Biologists therefore established a wildlife refuge on the island of Bugio to help with the reintroduction of the tiny snails. This reintroduction is “a major step in any species recovery plan,” adds Gerardo Garcia of Chester Zoo.

So far, everything seems to be going well. If this reintroduction achieves the hoped-for results, other snails will be released next spring. The objective is to reverse the situation to ensure the survival of both species in the long term.

Source: BBC