For at least four centuries the snap net fishermen of the south-east have employed their unique skills on the Barrow, Nore and Suir rivers.
Between now and mid-August, the two- and four-man crews engaged in this particular activity will be out in their flat-bottomed wooden boats fishing for salmon, using methods which haven't changed for hundreds of years.
It's a highly-skilled activity and one of the oldest methods of fishing in Ireland, but the current generation of snap net fishermen may well be the last. Once the mainstay of large sections of the population in the region, the sector is under attack from several quarters and stocks are diminishing rapidly.
If the skill is lost, warns Mr Peter Walsh, chairman of the Barrow, Nore and Suir Snap Net Fishermen's Alliance, it can never be revived, as there will be no one around to pass it on.
Snap net fishing involves the use of nets up to 18 yards wide which are held by the fishermen. In the case of two-man crews, one holds the net and another paddles. This method of fishing, which can only be practised at certain times on the ebb and flood of the tides, is unique to the south-east.
In his book published last year, Men, Tides and Salmon - Snap Netting on the Barrow, Nore and Suir, Prof Noel P. Wilkins, of NUI Galway, says the earliest documentary evidence of the activity dates from 1600.
Because of its specialised requirements - a level, muddy river bottom and a significant tidal flow - it only ever developed to any great extent in the Shannon and Maigue estuaries, the Slaney, the Munster Blackwater below Lismore and in the Barrow, Nore and Suir. Today it is confined to the "three sisters".
It was once a major economic support to communities in south Kilkenny as well as small parts of south Tipperary, Waterford and Wexford, says Mr Walsh, who lives near Mooncoin. "Snap net fishing sustained the whole family structure here during the Famine years. Nobody died here during the Famine because they were able to live on fish."
Recently, he adds, it provided an income to locals who spent the winter on building sites in Britain and returned home for the summer fishing season. Even today 132 commercial snap net licences are issued annually by the Southern Regional Fisheries Board, which translates into a part-time income support for approximately the same number of families.
It is now strictly part-time, however. Three years ago the snap net season was cut by almost 50 per cent, as part of a general move to protect fish stocks, and now runs from May 12th until August 15th.
On top of this, says Mr Walsh, the activity is under threat from five different sources: "Massive, indiscriminate, interceptive driftnet fishing at sea"; increasing pollution; hydroelectric weirs which prevent salmon from reaching traditional spawning areas; drainage work on the upper Barrow; and sprat weirs, which are killing large numbers of young salmon making their way to the sea.
"The snap net fishermen had 5 per cent of the national salmon catch in the 1970s. We are now down to 0.4 per cent," he says.
There is some hope on the pollution front, with the Barrow being included in a three-year project along with the Boyne and the Liffey to improve water quality. But unless the other issues are also tackled urgently, he warns, this centuries-old activity will disappear.