Anglers on Lough Derg claim fish stocks are so depleted in the lake they have had to cancel all competitions this year.
The Lough Derg Anglers' Association said a Central Fisheries Board five-year plan will not alleviate the pollution problems that have decimated fish stocks.
The "Save Our Lough Derg" campaign has called on the Minister for the Environment to ban phosphate-laden detergents which have been responsible for the deterioration of water quality.
The anglers admit, however, that water quality is improving and they hope new sewage treatment plants starting this year and next in the lake's catchment area will reduce the pollution.