Freshwater Pearl Mussel Rescue Project

The Ballinderry Freshwater Pearl Mussel Rescue Project (2013-2015) aims to save the Ballinderry freshwater pearl mussel from extinction by addressing the issues in the catchment which are preventing them from naturally recruiting and to raise awareness of this globally endangered species amongst the community.

The mussels in the Ballinderry are unique in that they are genetically distinct from all the remaining populations in Northern Irish rivers and, without intervention, at their current rate of decline will be extinct by 2098.

The project focuses on the upper 127km2 of the Ballinderry River catchment, County Tyrone, Northern Ireland. This catchment includes the main channel of the Ballinderry from its source at Cam Lough in the Sperrin Mountains to Cookstown (located half way down the Ballinderry River) and eleven tributaries. Within the project area, the Ballinderry River is designated as a Special Area of Conservation and an Area of Special Scientific Interest.

The £444,000 project has employed three dedicated staff members and delivered over £160,000 of silt remediation and river restoration works over 20 kilometres to improve the river to a standard in which freshwater pearl mussels can naturally reproduce and survive to adulthood.

In order to achieve our aims we have been:

1. Identifying the pressures in the catchment which are preventing mussels from naturally recruiting and surviving and addressing these issues at the catchment-scale.
2. Establishing a sanctuary population of freshwater pearl mussel comprising regrouped dispersed adult mussels and released captive-bred juvenile and young sexually mature adult mussels, complimented by improved stock densities of host fish.
3. Improving the captive-breeding programme and determining how young a captive-bred mussel can be released to the wild.
4. Delivering a learning and outreach programme aimed at the wider public through a variety of outlets and resources.

The methods used for identifying, planning and implementing silt remediation and education, outreach and communications were fully researched, evidence-based and defined as part of a six month project planning phase that saw, scientists, ecologists, conservationists, educationalist and statutory and non—statutory bodies contribute to a suite of project plans including a Conservation Plan, Education Plan, Volunteer Plan, Marketing and Communications Plan and an overarching Activity Plan. The Activity Plan provided determinate targets against which the success of the project is measured.

Monitoring surveys and results

The main aim of the project was to reduce the amount of silt entering the upper Ballinderry River. To identify critical source areas we surveyed 200 kilometres of riverbanks. Out of 75 landowners on whose land silt remediation measures were identified, 73 agreed to works being done. A significant number of farmers agreed to contribute to the work in-kind with time, machinery and materials. This contribution was valued at £40,000, in addition to the £100,000 silt remediation budget. An additional £20,000 was contributed by Inland Fisheries from NASCO funds. The £160,000 budget has delivered:

    • 20,000 meters of new or repaired stock-proof fencing resulting in 3,500 less cattle accessing the river now compared to summer 2014
    • 60 open livestock watering bays have been closed up and alternative watering supplied, using pasture pumps
    • 3,500 meters of bank revetments (soft and hard engineering) to prevent erosion
    • 4,000 meters of willow and alder planning along vulnerable river banks

Work has also begun on an Integrated Constructed Wetland to be used as a farm pollution control demonstration project. Already, farmers living in the upper catchment have reported that the riverbed appears cleaner than in previous years. Suspended silt levels are still being monitored by University of Ulster and we await the results. Similarly, silt levels in the gravel are being reassessed this summer. However, it is reasonable to assume that a significant reduction in silt entering the river has been achieved when considering the scale of the silt remediation works described above.

This work is now enabling us to release captive-bred juvenile mussels back to the river. Some have already been released and are being monitored. Survival and growth rates suggest that mass-release would be successful. By releasing these mussels we have already changed the extinction curve for the Ballinderry population. An independent mussel expert, Dr Evelyn Moorkens, has been quoted as saying that ‘the input of as little as 10 surviving juvenile mussels a year has the net effect of maintaining the population eventually at current levels’; 240 have been released over the last two years we are about to release 330 to two sites on the river. These numbers will shift the date of total extinction of the population far beyond the prediction (2098) and continued releases will avoid extinction entirely.

The project has been well publicised in various newspapers and on the BBC’s Countryfile programme. It has also featured in the UK Journal for the Quarry industry and in scientific journals. We have been making presentations on the project to Government Departments, farmers groups and at conferences whilst networking with other projects such as the Pearls in Peril Project in Great Britain and the Donegal Interreg Freshwater Pearl Mussel Practical Measures Project and Kerry LIFE project in the Republic of Ireland. From contact made at these events, groups including university students, NGO’s and environmentalists have visited our conservation breeding centre and silt remediation sites, comparing the work sites with photographs taken before the works started.

The silt remediation works have obvious benefits to species other than the freshwater pearl mussel. More salmon and trout eggs hatch when gravels are free of silt. An increase in fish numbers provides otter, kingfisher, heron and other piscivorous species a better environment to raise their young.

During the project many thousands of willow and alder trees were planted to stabilise eroding banks. The landowners concerned have agreed to train the height and width of the trees. When established in 3-4 years the tree-lined riverbanks will slow the flow of flood water both in the tributaries and the main channel. Flood relief in the middle and lower stretches of the Ballinderry will be delivered as a consequence of this project.

Economic benefits will be another outcome since the loss of land along the tributaries and main channel has been stopped and in several fields the over widened channel has been brought back to its natural width, bringing some 1,000 square meters of land back into agricultural production.

The project will help our Government avoid having to pay infraction fines if it cannot meet its obligations under the Water Framework and Habitats Directives; this is therefore a National economic benefit.

Most of the total project budget of £444,000 will have been spent in the Ballinderry catchment, providing an immediate local economic benefit arising from the project.

Our Learning and Outreach Officer has involved 24 schools in the catchment, in the mussel project. Both University of Ulster and Queen’s University staff and students have advised on and actually delivered this project. A Queens’ PhD student will complete her research in 2015; research which would not have been possible without the project on the ground.

In addition, landowners, quarry owners and other business owners along with school teachers, students and volunteers have attended stakeholder meetings.

All of this engagement work has made the whole community more aware of how vulnerable and valuable the freshwater pearl mussel is. River recreation and sports will also benefit from this project as a result of improved water quality, more fish for angling and greater biodiversity value as the Ballinderry River remains home to the freshwater pearl mussel.