Plea to help save one of Devon’s most endangered species

A conservation project which aims to save one of Devon’s most endangered animals is now urgently seeking donations from the public so that it can continue its vital work.

The freshwater pearl mussel might not look as stunning as some wildlife but the conservation charity Devon Wildlife Trust describes it as a ‘remarkable animal’ and one that can have a positive impact for us all.

Freshwater pearl mussels filter bacteria and algae. So a large population helps to clean up our rivers for the benefit of other wildlife - and people.

They have been wild residents of Devon’s rivers for thousands of years. But now the mussels are declining significantly across their range and in the whole of Devon they are only found on the Torridge and the Taw.

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

Devon Wildlife Trust is working to clean up the river and to breed mussels in captivity - so they can survive in healthy water at their earliest stage of life, before being returned to the wild. However, it now needs to fill a £9,000 funding gap in the project and is asking people to help.

In her role as Freshwater Pearl Mussel officer for the national ‘Restoring Freshwater Mussel Rivers in England’ project, Devon Wildlife Trust’s Izzy Moser has been working with landowners to help improve water quality in the River Torridge for the last two years. She is also involved in the captive breeding programme, as part of this nationwide effort co-ordinated by the Freshwater Biological Association.  

Izzy Moser 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 amazing 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. Once they are big enough, the larvae will drop off the fish, down to the gravel bed of the tanks and then grow to become juvenile mussels.

And the juveniles then have a real growth spurt, growing approximately 200% bigger in their first year.

But even in unpolluted rivers, only an average of five larvae from the five million released by an adult mussel each year will survive to become an adult freshwater pearl mussel.

The next stage of the project is crucial. Izzy will have to move the juvenile mussels from their gravel habitat in the tanks, to specially selected points of the Torridge riverbed - and then monitor these sites to check on the progress of the first young mussels on the river since the 1960s.

Although this project is largely funded by Biffa Award, Devon Wildlife Trust 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 said: “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. And by supporting work to improve water quality in one of Devon’s grandest rivers – the Torridge – they’ll be helping a wide range of other wildlife too, including otters, dragonflies, bats and kingfishers.

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

Photos show freshwater pearl mussels in a tank at the hatchery in north Devon; Devon Wildlife Trust’s Izzy Moser inspecting a freshwater pearl mussel for larvae; Izzy Moser in the River Torridge.