The many rivers and streams entering Lough Foyle have large runs of salmon in the summer and autumn. The salmon is native to Ireland, a migratory fish hatched and nurtured in mountain streams and rivers before going to sea as smolts. Maturing in the north Atlantic, salmon make their way back to the waters where they hatched a few years before. There, the hen fish makes a redd or nest in the gravel bed of a stream, where she deposits her eggs to be fertilised by the cock fish.
Sea trout are the anadromous form of the resident brown trout, meaning that they migrate to sea to feed and return to freshwater to breed - whereas the resident brown trout remains in freshwater for its entire life. Sea trout follow a similar life cycle pattern to Atlantic salmon in that they smolt and migrate to sea. Sea trout do not undertake as lengthy a marine migration as Atlantic salmon and may, in fact, return to the river and move back to sea repeatedly. Sea trout that feed in the Atlantic are normally smaller than their cousins that feed in the Irish Sea. Fishing for sea trout has similarities with salmon angling, though the tackle is lighter and sea trout - unlike salmon - are often fished for at night. Sea trout spend a large proportion of their life feeding in the rich waters in and around the sea lough and it is in this environment that they are targeted by anglers specialising in estuary/saltwater fishing from shore and boat.
The resident brown trout remain in freshwater but otherwise follow the same life cycle stages as both salmon and sea trout - without the marine phase.
Also present in some of the rivers within the Foyle catchment are pike, perch and roach. Great sport can be enjoyed targeting these species when the game fishing season has finished.