Ecological Consultancy Services Limited (EcoServe)
Annual monitoring of the distribution and abundance of the River Nore pearl mussel
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Client: Arcon Mines
Date: 1996-2000
Margaritifera durrovensis is protected under the Wildlife Act, EU Habitats Directive, and Bern Convention, and is one of only two endemic species in Ireland. It is closely related to the southern European hard-water pearl mussel Margaritifera auricularia, and the more widely distributed soft-water mussel Margaritifera margaritifera. EcoServe conduct an annual survey of M. durrovensis for Arcon Mines Ltd which follows on from the surveys conducted by Evelyn Moorkens as part of her PhD.
In parts of the river mussels have been surveyed for 6 years and will continue to be surveyed in future years. In contrast to healthy populations of M. margaritifera in which hundreds of mussels may occur over a few square metres, only widely scattered individuals and clusters of M. durrovensis exist. No juvenile mussels (less than ca. 8 years of age) have been recorded during these surveys. The single population of M. durrovensis is thus threatened with extinction.
Bibliography
Moorkens E.A., Costello M.J. and Speight M.C.D. 1992. Status of the freshwater pearl mussels Margaritifera margaritifera and M. m. durrovensis in the Nore, Barrow, and Suir river tributaries. Irish Naturalists' Journal 24, 127-131.
Moorkens E.A. and Costello M.J. 1994. Imminent extinction of the Nore freshwater pearl mussel, Margaritifera durrovensis: a species unique to Ireland. Aquatic Conservation: marine and freshwater ecosystems 4, 363-365.
Costello, M.J., Moorkens E.A., Larkin M. and Kurz I. 1997. The River Nore and its almost extinct pearl mussel: a priority for management and river restoration. In: Colloquy on conservation, management and restoration of habitats for invertebrates: enhancing biological diversity. Killarney, Ireland, 26-29 May 1996. Council of Europe, Strasbourg, Environmental encounters no. 33, 31-37.
Costello, M.J., Moorkens E.A., Larkin M., Kurz I. and Dowse J. 1998 Management priorities for the River Nore (Ireland) to conserve the pearl mussel, Margaritifera durrovensis. Journal of Conchology Special Publication No. 2, 257-264.