A new joint initiative between the Marine Institute and the National Parks and Wildlife Service (NPWS) aims to revitalise the freshwater pearl mussel through a pilot captive breeding programme.
Pearl mussels are capable of surviving for up to 140 years, making them Ireland’s longest living animal.
But environmental changed have put them on the verge of extinction. The species is listed as Endangered on the IUCN Red List, and is one of the 365 most endangered species in the world.
In Ireland, 19 Special Areas of Conservation (SACs) have been designated in an effort to conserve the pearl mussel in its native habitats.
‘We are hopeful that over time this joint project will lead to a positive outcome for the freshwater pearl mussel in Ireland’
And the new programme — to be based at the Marine Institute’s Newport Research Facility in Co Mayo, close to one of the last remaining reproducing populations of freshwater pearl mussels — is hoped to safeguard the survival of the rare species into the future.
“Captive breeding programmes are already well established in several countries, and we are hopeful that over time this joint project between the Marine Institute and the National Parks and Wildlife Service will lead to a positive outcome for the freshwater pearl mussel in Ireland,” said Dr Áine O'Connor of the NPWS.
One of the reasons for the decline of the freshwater pearl mussel is the low survival rate among juveniles, which are extremely sensitive to slight changes in environmental conditions. This is leading to an ageing population, not capable of replenishing itself.
Juvenile survival is dependent on a clean riverbed, with little silt, sediment or algal growth. These mussels also have a very unusual life cycle, in that they are dependent on the Atlantic salmon and brown trout to host their larvae, called glochidia, for about 10 months. The captive breeding programme is targeted at this crucial life stage.
‘This small experimental population will be given a year to see if the juveniles grow to the stage where they can settle themselves in a suitable habitat’
Work on the programme began this past June when a tank in the Marine Institute’s hatchery was set up with 300 juvenile salmon. In July, 30 adult mussels were removed from the Newport River and transported to the tank.
The project team are currently waiting to see if mussels will release glochidia and whether these will naturally attach themselves to the gills of the salmon.
If successful, the Marine Institute and NPWS will maintain this small experimental population for a year to see if the juveniles grow to the stage where the mussels can detach from the fish and settle themselves in a suitable habitat.
“Historically, we know the Burrishoole catchment [in the area around Newport] contained pearl mussels, which gives us some confidence that the water supply to the hatchery on Lough Feeagh is suitable for long-term maintenance of the mussel populations,” said Marine Institute zoologist Dr Elvira de Eyto.
The pilot captive breeding programme is a partnership between the Marine Institute and NPWS in conjunction with freshwater pearl mussel specialists Evelyn Moorkens and Ian Killeen.
