Wild Atlantic salmon have begun reproducing in Dublin's Tolka River for the first time in at least 100 years.
The re-colonisation was spotted by Inland Fisheries Ireland during a recent review of fish stocks.
Following works carried out as part of the Tolka River's flood relief scheme, a number of man-made weirs were removed or modified - thereby opening up the river to migratory fish.
Now, young wild Atlantic salmon have been sighted in three locations in the Tolka in the Glasnevin and Finglas areas.
As salmon can only survive in clean water, their presence also reflects efforts to reduce pollution levels in the river.
Inland Fisheries Ireland says in environmental terms the discovery is an important step forward.
Dublin now has three rivers producing wild salmon stocks - the Liffey, Dodder and Tolka - making it the only European capital city to hold such an accolade.
