Most brown trout fisheries open between February 15th and March 17th. Most close on September 30th with some exceptions which close on various dates between September 15th and October 12th. Clubs may have their own regulations on opening and closing dates.
The behaviour of trout depends on the amount and type of their food supply. This will depend on the habitat. Trout in the nutrient rich / limestone waters will have a good and constant food supply but those in more acidic waters have to be more opportunistic in their feeding patterns. Warm settled periods tend to lead to large fly hatches and these will usually trigger trout to feed on the surface. In limestone habitats the trout will spend a lot of time ‘grubbing’ around the bottom and in weeds for food, but in more acidic waters with poorer food supplies they will be more focused on food blown onto the water.
Behaviour can be greatly affected by many factors, including the month, prevailing weather conditions or even the time of day.
Early in the season, most fish will be feeding hard to regain condition after the rigors of spawning and the restricted food supply of the winter. Trout in the loughs will feed on hog louse and shrimp but will rise for the early hatches of duck fly.
Ireland is justly famous for its mayfly hatches that can start as early as April and go through to July, though the peak of the hatch varies from lough to lough.
Warm summer evenings herald the arrival of the sedges and toward the end of the season the trout may be given a final feast of daddy long legs (crane flies) that can produce excellent top of the water sport.
It is also worth keeping an eye out for trout feeding on fry in the autumn. This is a very rich food supply and allows trout to put on plenty of weight. This will often also lure the larger fish to come and join in the feast.
Limestone rivers generally produce heavy hatches of ‘up winged flies’ (ephemeroptera). These start with the large dark olive of early spring, to medium olives, iron blue duns and the blue winged olives in summer.
Sedge species are also an important food supply particularly as the summer progresses. It is important to be aware of these species and have a few suitable patterns to hand, as when they hatch in large numbers trout can get totally preoccupied.
Throughout the season aquatic hatches are boosted by the appearance of terrestrials such as the hawthorn, beetles, cow dung and of course daddy long legs. In addition such streams will have large populations of crustaceans.
The trout of more acidic rain-fed rivers tend to be more opportunistic feeders. Such rivers may well have hatches of ephemeroptera, but terrestrial flies will be more important here, especially in upland or moorland rivers. The dry fly will catch, but the wet fly is more important, as is a selection of more general and less imitative flies.
The time of day is important. Early in the year feeding is often restricted to warmer times of the day from 11 to 14.00. However as the year progresses trout do not like bright light and so in summer their feeding can be restricted to early morning and late evening. Dawn can be a magical time on many fisheries with hatches of fly from 4 am onwards. Conversely all trout anglers will be familiar with the evening rise. When the sedges are around this can last all night.
Large trout are large because they are careful. However, anglers do have an opportunity to catch one of these fish when water is clearing after a flood or during large hatches of fly on loughs. Many specimen brown trout have been caught during the mayfly hatch, when chasing sedges in the dusk or taking a trotted worm. Behaviour will vary on different waters during the year. Check with local tackle shops or an angling guide or ghillie for the best taking times on the fisheries you are looking to fish and the best time of season to try for a large trout.
Climatic Influences on Irish Wild Brown Trout
Trout may be fished for from February through to October. At all times the fishing depends on prevailing weather, water levels, barometric pressure and temperature. The influence of the Irish climate, as well as the habits of the trout, also has to be taken into account. Most Irish rivers and loughs are subject to seasonal rhythms of high and low water. The high winds of spring and autumn can render boat fishing on the bigger loughs unsafe for short periods. However, trout fisherman in Ireland can usually find sheltered waters available when others are affected by floods or gales. When water levels are high and some fisheries are unfishable, rivers like the Cong can be the place to fish. Hot summer temperatures are probably the only time of year when trout are not active during the daytime period.