The Most Threatened Species named in the report
Freshwater Pearl Mussel
The freshwater pearl mussel lives in "soft" water
rivers, mainly in the west of Ireland but also in areas of the
south and southeast where granite or sandstone rock occurs.
Individuals grow very large, building up thick shells, and live to
over 100 years of age. Threats include severe nutrient enrichment
of the water as well as silting. A recent survey of 23 populations
of pearl mussels concluded that none could be considered
viable.
The species is listed as "critically endangered" in Ireland in the most recent review by the International Union for Conservation of Nature (IUCN).
Pollan
The Irish population of pollan is the only one in
western Europe and is almost unique in being confined to freshwater
lakes. Pollan is found in five large lakes, including Lough Derg,
Lough Ree and Lough Allen, on the River Shannon; the other two,
Lough Neagh and Lough Erne, are in Northern Ireland. The species is
now at "critically low levels" with only hundreds or very low
thousands of fish remaining in each of the three Shannon lakes
— mainly due to eutrophication, climate change and the
introduction of alien zebra mussels.
Nore Pearl Mussel
The Nore freshwater pearl mussel is currently known
only from the lime-rich waters of the river Nore and does not live
in acid waters like its close relative, Margaritifera
margaritifera. This species was previously known from the Barrow,
Nore and Suir, but living specimens have not been found outside the
Nore since 1993. The most recent survey of the total number of
extant Nore pearl mussel adults in Ireland is 500 individuals
— a decline of 75 per cent since 1991.
Atlantic Salmon
Ireland's salmon population has declined by 75 per
cent in recent decades and, although salmon still occur in 148
Irish rivers, only 43 of these have healthy populations. Numerous
factors include reduced marine survival (probably as a result of
climate change), poor river water quality, forestry-related
pressures and over-fishing. Current estimates suggest that less
than 10 per cent of the wild smolts that go to sea from Irish
rivers are surviving.
Desmoulin's Whorl Snail
With a shell height of about 2.5mm, this is the
largest whorl snail in Ireland. All whorl snails favour damp or wet
habitats, such as swamps or fens, and the Desmoulin variety is
particularly sensitive to changes in water levels.
The greatest loss of habitats for this species has been through drainage of wetlands, and water management of the Grand and Royal canals.
Natterjack toad
These are found in a small number of coastal sites
around the Dingle and Iveragh peninsulas in Co Kerry. The toad
breeds in shallow ponds and lakes, and recent surveys put the
population at 12,000 adults. Its range has contracted significantly
due to the loss of breeding ponds following land drainage. A study
carried out in 2004-2006 indicated that the range is at risk of
contracting further, with very poor and irregular breeding activity
recorded at Fermoyle, the most westerly part on the Dingle
peninsula, despite the creation of two additional pools.
Twaite shad
These fish spend their adult life at sea or in the
lower reaches of estuaries and normally spawn near the tidal
limits, so unimpeded access from the sea through the estuarine and
tidal areas to the spawning grounds is essential. Gravel must be
clear of algal growth and fine deposits. Spawning activity has only
been recorded in five large rivers in the southeast: the Barrow,
Munster Blackwater, Suir, Nore and Slaney. Even in these rivers
population levels are thought to be low.