Advice on Trout Fishing


This article is written by one of our experienced members to provide guidance to the fisherman wanting to try fly fishing for trout on the River Usk.


A 4lb Usk Brown Trout Caught on a Light Cahill

The River Usk is recognized as one of the best wild trout rivers in the UK, capable of producing brown trout up to five pounds in weight with the average fish being around a pound. The insect life inhabiting the river is both diverse and plentiful and includes a variety of up-winged flies, caddisflies, stoneflies and a selection of terrestrial flies. The ISCA Angling Club has fishing access to different beats spread along the Usk valley starting from the tidal beat located down-stream of Newbridge-on-Usk with additional beats (upstream) as far as Abergavenny. Although the Newbridge beat does have a significant population of trout, most anglers here focus on salmon fishing.

The River Usk provides a diverse habitat for wild trout with most pools possessing classical features starting with a fast run, a slow and deeper body leading into a gliding tail. Trout can be found feeding in areas such as the eye of the pool, behind or in front of various boulders or behind a shelf, in margins close to the bank as well as in the tail of the pool. After a spate, the river will become coloured but within a few days becomes very clear again. It is then possible to see and identify promising pockets of water. Combining these attractive features with a rich supply of invertebrates, fly fishing the Usk is a delightful but also testing experience as finding the right fly to match the hatch can be a challenge.

A 9ft or 10ft fly rod with a 4wt or 5wt line is ideal for fishing the Usk and it’s advisable to use a tapered leader with a selection of tips (copolymer or fluorocarbon) in the range of 3lb to 5lb breaking strain.

In early spring, fly hatches are generally seen during the warmest part of the day. Large Dark Olives (LDO’s) and occasional, but in recent years more frequent, hatches of March Browns provide short lived but exciting moments as good numbers of trout rise enthusiastically for both the adult or emerging forms of these flies. Also hatching at this time of year, are Grannum sedge flies which fill the air in large clouds as they return to lay eggs. Given a warm spring the chances of good sport are normally improved especially if the angler is able to fish between 10am and 2pm. On colder days when there is little surface activity, there are alternative options such as fishing a team of spider patterns (eg. Black and Peacock, Usk Naylor and Greenwell Spider).

May and June are amongst the best months of the year because the fly hatches expand in terms of diversity, numbers and duration. The variety of aquatic flies includes Sedges, LDO’s, Iron Blue Duns, Pale Watery Duns, Olive Uprights, Green Drakes, Large Brook Duns, Yellow May Duns and Blue Winged Olives. At times, a number of terrestrial flies can also appear on the menu notably the Hawthorn fly. Depending upon the conditions, the trout can change their feeding focus between a number of different types of flies and the occurrence of hatches can fluctuate through most of the day. Nevertheless, on some occasions the trout can be preoccupied with targeting a single fly. This can be frustrating but also very rewarding if the angler can identify the ‘fly of the moment’. Amongst the various invertebrates, Yellow May Duns [YMD] (Heptagenia Sulfurea) and Green Drakes (Ephemera Danica) will often hatch over sustained periods of time (sometimes hours) and both are very popular with the trout. In recent years, farming practices have resulted in deposition of fine-sand beds along the river margins and this new habitat has led to an increase in Danica mayflies which like to burrow in sand during their nymphal stage. During its transition from nymph to adult, the YMD is very different from other types of invertebrates because it needs to unpack its wing-case whilst on the bed of the river before swimming to the surface. Using emerger patterns which incorporate these wing-like features will certainly improve catches during a hatch of YMD’s. When fishing in the early morning or late evening, it is always worth investigating the river margins for signs of trout feeding on small sedges (Agapetus). Prior to hatching, these small sedges transform into free swimming pharates and often attract the attention of larger trout.

The Table below provides a number of recommended flies for the trout fisherman depending on the time of year and taking into account when the different types of flies appear on the river. Suggestions are also provided on where the flies can be purchased; for the fisherman who might not have the time to tie flies for themselves.

In July and August, both the river and the air temperature will increase and the river level usually will fall. Surface feeding activity tends to decline during the middle of the day and shifts into early morning and late evening. However, during these summer months YMD’s and Green Drakes continue to hatch in good numbers and these patterns are still a reliable option. In late evening, female YMD’s will leave the trees in large numbers and return to the river to lay their eggs. After sunset, the trout will feed for surface flies with a lot more confidence and some spectacular sport can be enjoyed if the angler can cope with the reduced visibility. Other flies that appear at this time include LDO’s, Pale Watery Duns and Blue Winged Olives.

Trout Flies for the river Usk

Recommended trout flies for the river Usk


Light Cahil dry fly

Light Cahill – a general pattern for Danicas and Pale Watery Duns


Yellow May Dun Fly

Ascending Yellow May Dun Emerger

Despite hot and bright conditions during the summer period, it is still possible to catch trout in the middle of the day by using weighted nymph patterns fished on or near the bottom of the river bed. This approach calls for long leaders and a team of 2 or 3 flies and can either be achieved using a longer rod (10 to 12ft) with a sink tip fly line or alternatively a Czech nymphing set-up. Some useful nymph patterns for the Usk include Shrimps (olive and orange), Pheasant tails, Sedge pupa (in olive, orange and dark green) and Cased Caddis. In September, the evenings start to become darker and slightly colder and so good sport can again be enjoyed during the daytime. At this stage of the season the main adult flies of interest include LDO’s, Pale Watery Duns and Sedge patterns. In addition, trout will start to feed on small fry especially in the shallow margins. It is then well worth carrying a selection of streamer-flies and fry imitations and in late season these patterns can attract some hungry large trout.