Donal Hickey: Sewage pollution and the pearl mussel

Once widespread, they are now found in very few catchments. Ireland is believed to have almost half of Europe’s pearl mussel population, with the Blackwater catchment accounting for a sizeable portion of that

The catchments of the Munster Blackwater and river Araglen, in north Cork, are among the pearl mussel's remaining habitats. Picture: Larry Cummins

The odds of finding a pearl in a pearl mussel are reckoned at around 10,000/1. But, such has been decline in this critically endangered species in our rivers, you’d be lucky to find a mussel, never mind a pearl.

Numbers have dropped so much that it would be simply untenable to catch them: better to protect what little remains of the species.