Sustainable catchment restoration for reintroduction of captive bred freshwater pearl mussels Margaritifera margaritifera

Abstract

Please cite this article as: Horton, M., Keys, A., Kirkwood, L., Mitchell, F., Kyle, R., Roberts, D.,Sustainable catchment restoration for reintroduction of captive bred freshwater pearl mussels Margaritifera margaritifera., Limnologica (2014), http://dx. AbstractThe Ballinderry River, Co. Tyrone (SAC), is one of only six rivers in Northern Ireland that still supports a population of the globally endangered freshwater pearl mussel, Margaritifera margaritifera. Fewer than 1000 individuals still exist in the river; without intervention it is predicted the Ballinderry pearl mussel will be extinct by 2098. This paper aims to identify key catchment pressures on remaining mussel stocks and prioritise tributaries within the catchment for remediation work to ensure effective targeting of limited resources. A combination of redox assessment, river surveys and SCIMAP modelling was used to rank tributaries, taking into consideration their size and proximity to the main mussel population at the "sanctuary site". Diffuse and point sources of sediment were identified within the prioritised catchment. The Tulnacross tributary was selected as the highest priority tributary and has been used in a pilot remediation study. A number of different hard and soft engineering techniques have been used for remediation as well as replacing cattle drinkers with pasture pumps and fencing alongside the river. Initial observations suggest river substrate is cleaner. This study is an example of how to tackle problems within a large-scale catchment with limited resources with participation of local stakeholders and riparian landowners.

Development of release methods for captive‐bred freshwater pearl mussels (Margaritifera margaritifera

“…Extensive surveys were carried out along the Ballinderry River catchment to identify two suitable sites to test the release of juvenile M. margaritifera into mussel silos. Site 1 was a tributary of the main Ballinderry River channel selected because of high water quality and the presence of suitable habitat, such as cobbles with gravel for burrowing and bankside vegetation (following Wilson et al , ; Horton et al , ). Site 2 was on the main Ballinderry River channel with suitable habitat (following Wilson et al , ) and a nearby extant remnant, non‐functional, adult mussel population.…”

“…Total species extirpation in Northern Ireland has been predicted by the year 2098 (Wilson and Roberts, ). Surveys have shown that there are fewer than 1000 wild mussels in the Ballinderry River (Reid et al ., ); these declines are linked primarily to habitat degradation and declines in host fish (Horton et al ., ).…”

An alien fish threatens an endangered parasitic bivalve: the relationship between brook trout (Salvelinus fontinalis) and freshwater pearl mussel (Margaritifera margaritifera) in northern Europe

“…Many conservation strategies for the restoration of FPM populations have been developed; habitat protection and restoration , Bolland et al 2010, Geist 2010, Horton et al 2015 probably are the primary strategies but methods such as reintroduction of mussels (Young and Williams 1983b, Valovirta 1993, Beasley and Roberts 1999, Bolland et al 2010, Geist 2010, release of glochidia-infected fish (Buddensiek 1995, Geist et al 2006, Thomas et al 2010, Simon et al 2015 and artificial culture of mussels (Buddensiek 1995, Preston et al 2007, Geist 2010, Schmidt and Vandré 2010, Thomas et al 2010, Gum et al 2011, Simon et al 2015 are also widely used. However, despite the conservation activities, increased freshwater mussel research (see e.g.…”

The current status and future challenges for the preservation and conservation of freshwater pearl mussel habitats

“…Especially the role of fine sediment accumulation reducing the redox potential and thus influencing juvenile mussel habitats has been highlighted several times. Exemplarily (Horton et al, 2015), identify diffuse and point sources of sediment as possible trigger factors within a large-scale perspective (catchment scale) for clogging river bed surfaces in Northern Ireland. In Austria, on a local scale, Scheder et al (2015) investigated sediment clogging and its impact on the interstitial habitat quality in relation to variable hydro-morphological boundaries (near natural river sites vs. artificial millrace).…”

“…The restoration strategy for the Rede pearl mussel population (England case study presented by Gosselin (2015)) should focus mainly on limiting sediment and nutrient input into the river throughout the catchment in order to improve habitats for juvenile pearl mussels. Land use was also addressed on the catchment scale, both by Popov (2015) who points out that the preservation of forest vegetation along the river banks correlates with the presence of pearl mussel populations; -and by Horton et al (2015), who mention a number of different hard and soft engineering techniques for remediation, like fencing for cattle alongside the river. Different wording but similar meaning according to possible mitigation measures on various spatial scales have been reviewed and discussed by Hauer (2015), concerning possible structural (e.g.…”