The humble freshwater pearl mussel may not look like a lot - but did you know it’s a key factor in keeping North Devon’s rivers clean?

The freshwater pearl mussels in a tank at the hatchery in North Devon.The freshwater pearl mussels in a tank at the hatchery in North Devon.

A conservation project to protect an animal unique to the Taw and Torridge is in desperate need of funding.

Devon Wildlife Trust (DWT) is urgently seeking donations to fill a £9,000 funding gap to breed the 'remarkable' freshwater pearl mussel.

The mussels filter bacteria and algae, so a large population can help to clean up the rivers for the benefit of wildlife and people.

Their numbers are declining significantly, and the Taw and Torridge are now the only places these mussels can be found across Devon.

Izzy Moser of DWT in the River Torridge.Izzy Moser of DWT in the River Torridge.

But even these rivers are too polluted for the mussels to breed successfully.

Although they can live to 130 years of age, the youngest freshwater pearl mussels on the River Torridge were born in the 1960s.

DWT is warning that if they are unable to breed, this unique animal will be lost from the county.

This is why the trust is hoping to breed the mussels in captivity, so they can survive in healthy water during their early life, before being returned to the wild.

Izzy Moser, freshwater pearl mussel officer for the national Restoring Freshwater Mussel Rivers in England project, has been working with landowners to improve water quality in the Torridge.

She said: "This winter, we had some great news: the first signs of breeding success for freshwater pearl mussels from the River Torridge in more than 50 years."

This animal's life cycle involves a stage of living on the gills of Atlantic salmon or brown trout, so right now, the fish - and the mussel larvae - are all in tanks in a hatchery in North Devon.

Although this project is largely funded by Biffa Award, DWT has to find a further £9,000 to cover the costs of this critical work on the freshwater pearl mussel project over the coming months.

Izzy Moser added: "Despite the projects recent successes, there is still a significant amount of work to be done on a catchment scale to reduce run-off from farmland, roads and domestic sources and protect our local waters.

"We have already planted 80 trees and 250 willow stakes this year to reduce riverbank erosion, and fenced 1km of river but there is much more to be done."

Anyone making a donation to the Freshwater Pearl Mussel appeal will be playing a role in the rescue plan for one of Devon's most endangered creatures.

People wanting to make a difference to one of Devon's most endangered species should visit www.devonwildlifetrust.org/freshwater-pearl-mussel-appeal