A Strategy for Conservation of the Freshwater Pearl Mussel in Ireland

Sept 2011

The strategy prioritises eight of the 27 populations and encompasses approximately 9.6 million or 80% of the Irish freshwater pearl mussel population.

Summary perhaps explains why Ireland has limited FPM conservation measures to 8 sites, and why focus is on agricultural pressures (which is one of the pressures on FPM)

Ireland equates to approximately 37% of the EU freshwater pearl mussel population.

Strategy also proposes particular measures for the Nore pearl mussel population and a freshwater pearl mussel population in the South East.

The most significant pressures across the 27 catchments are:
(point sources)
o Quarries, sand and gravel pits
o Wastewater treatments plants (WwTP)

(diffuse sources)
o Agriculture (including overgrazing)
o Forestry
o On-site wastewater treatment systems (OSS)

Other more localised pressures include

peat extraction,

flow regulation,


morphological changes to the river bed and banks

Prioritisation of the 27 Irish SAC populations of freshwater pearl mussel, following the application of five filters (Moorkens, 2010)

Note: within a priority class, populations are not listed in ranked order.

“With the exception of the Bundorragha, all of the Group 1 catchments have had significant increases in pressures recently, including increases in once-off houses, land reclamation and clearfelling of coniferous forestry. If measures are not now taken, habitat conditions are likely to deteriorate further such that minimal or no recruitment will take place and ultimately leading to increased adult mortality.”

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