TROUT (salmo trutto) The relatively unpolluted waters of Ireland are one of the last few places where you can find truly wild trout. There is no licence required for trout fishing in the Republic of Ireland unlike Northern Ireland. In some cases permits are required but not for Lough Derg. Brown trout are a native Irish species and like all water types. The limestone bed of Lough Derg is rich in food and therefore produces trout of a good average size. Every year in Ireland trout of over 10lbs in weight are caught and sometimes even 20lb fish are hooked. Croneen and Ferrox are the most popular varieties in the lake. Fly-fishing, spinning and baiting are the most common methods used. The fishing season is open from March 15 to September 31 in the Shannon catchment area.