Scarce Yellow Sally insect returns after extinction fears

Scarce Yellow Sally, which is a tiny river fly, was thought to have died out back in 1995.

However, following pioneering conservation work at Chester Zoo, a small number were rediscovered in a short stretch of the River Dee in North Wales.

The discovery prompted scientists to launch a rescue mission to try to save them.

Insect feared extinct in Britain 'comes back from the dead' after 28 years

Now, the critically-endangered creature has been bred by a team of aquarists at Chester Zoo for the first time ever.

Joe Chattell, an aquarist at the zoo, said: “When just 30 scarce yellow sally stoneflies arrived at the zoo, the scientific data on the species was extremely limited.

"They were so few in number and, living for a period of just four to six weeks as adults, we really had no room for error in our efforts to save them.

"We had to learn as much as we could, as quickly as we could, to help them back from the brink.

“We’ve been able to record and document every tiny detail about the stoneflies and their larvae – beginning by replicating their wild environment, which is highly-oxygenated water on the riverbed caused by water passing over cobbles, in our specially created breeding facilities.

"We then tweaked the lighting and temperature conditions each day to mimic a normal 24-hour cycle, while also including seasonal variations – a lot of intricate work goes into saving a tiny insect from extinction.

Following pioneering conservation work at Chester Zoo, a small number were rediscovered in a short stretch of the River Dee in North Wales. ( SWNS) (Image: SWNS)

“In just a few weeks we were able to understand the species and its lifecycle, breeding patterns and favoured environment.

"Everything we have learned so far, including every slight tweak we made, has been meticulously recorded and given us a detailed blueprint which we hope will set the foundations for a conservation breeding programme for the critically endangered insect - all while helping to further increase the small surviving population in the River Dee.

“We’re enormously proud to be the first zoo to successfully breed this special stonefly, adding valuable scientific insight into the project with our partners, Buglife Cymru, who are safeguarding the species and its future here in the UK.”

The experts believe that this is the first time that the species has been successfully bred and reared through its complete lifecycle in a zoo setting outside of its river habitat.