THEY once flourished in every Irish river and stream.
But now there are fears that otters will become an endangered species in their former stronghold due to loss of habitat, poaching and competition from non-indigenous species.
However, an ambitious project in Duhallow in north Cork aims to reverse the decline as part of a €1m campaign.
It is estimated that Ireland has around 12,000 otters -- but their numbers and activity has dramatically declined over the past 50 years.
In 1981, otters were found at 88pc of Irish sites surveyed -- but, by 2005, that had slumped to 70pc.
The new campaign -- funded by the EU's LIFE project -- will see a regional development company, IRD Duhallow, working with Inland Fisheries Ireland (IFI) to try to support otter populations in the Rivers Allow, Dalua and Brogeen in the north of the county.
All three are strategic tributaries of the Blackwater -- one of Ireland's foremost fishing rivers and, for centuries, a stronghold of the European otter.
A three-month study of otter activity along the three river valleys has been completed.
The project will continue until 2014 amid concerns that Ireland could follow other EU countries where the otter has become an endangered species or extinct.
Project director, Pat Fitzpatrick, said one of the tributaries, the River Allow, had 60pc otter activity at sites surveyed -- while the River Brogeen had just 10pc otter activity.
"This forms the baseline for the first year of the project. Subsequent studies will be benchmarked off this data as the project progresses," he told the Irish Independent.
"An important element of the project is the placement of otter-holts, or specially constructed breeding boxes, in areas where otter occurrence was low,'' he added.
It is hoped that otters can be re-introduced to areas which were once a key part of their breeding grounds.