Cold River Trout

Tom Jarman makes the most of early season on the rivers

After a long winter and closed season, I’m always eager to get back onto a favourite trout stream and have some fun. But early in the season the fishing on the rivers can be a little slow. Snowmelt and late winter rains will mean higher flows and colder water in many fisheries, whereas others with reduced flows will be even more affected by short days and frosty nights, running cold, clear and low.
But what does this mean for our cold-blooded trout? At low water temperatures their metabolism slows down, reducing appetite and digestion. Under these conditions the trout become lazy and lethargic, and will seek out slower and deeper water.
Arriving at a stretch of river, the first thing we need to consider is where the fish are most likely to be positioned. No angler is capable of catching all of the available trout, so targeting the easy fish is the most efficient way to spend our time. This is essentially the art of ‘reading the water’, and this will change depending on the time of year and conditions. When the water is cold, anywhere the fish don’t need to work too hard against the current is a logical place to start.
Good examples of early-season water include pools, deep holes, the back or lower half of runs, and pockets or soft seams created by structure such as rocks and timber. Even just the soft cushions or slower water on the edge of the stream can be great.
Techniques that are most productive when the water is cold revolve around nymphing. This is because we can present the fly to the fish so they don’t need to move far to eat it. This doesn’t mean that dry fly fishing is a waste of time, as trout will sometimes rise to midges and small mayflies in pools in the coldest of weather. However, you will catch more trout when fishing nymphs.
In flat water such as pools or slow runs my go-to technique is nymph-below-dry. Here the flow is generally quite uniform, allowing you to achieve a long drift without drag, and this is why nymph-below-dry is so effective in this water type. Long drifts mean you cover good amounts of water with each cast and your fly is in the zone for longer periods. In the slow water, it also gives the fish time to find your fly and move to it if necessary.
You can also fish this water effectively with a pinch-on or yarn strike indicator, with a single nymph below. But I prefer to fish a dry fly as my indicator because trout will occasionally come up to eat the dry in slow water. A size 14 CDC sedge is a favourite, as it can support a reasonably weighted nymph, and trout of all sizes will take it with confidence. Wulffs and parachute mayflies are also perfectly suitable.
When selecting a nymph I prefer a small, lightly weighted fly. A 2.5 mm bead is an ideal weight, and size 16 and 18 hooks are perfect. For me, it’s important that the nymph is slim or sparsely tied. This will allow it to sink to depth quickly and drift nicely as it is not overdressed or overweighted. Pheasant Tail and Perdigon nymphs are perfect examples of this style of fly.
The distance between your dry and nymph is very important because the fish are quite lethargic at this time of year and we need to make sure that the fly is getting down. Fishing 60–70 cm between dry and nymph is a great starting point. If I encounter deeper water I will not hesitate to lengthen this to a metre or longer if needed. Similarly, if the water is very shallow, shortening this distance is just as important.
On a river with limited flat water, sometimes the best early-season holding water comes in the form of slack pockets and soft seams behind structure, or in the cushions and soft edges tight to the river bank. This water can be quite complex, as many currents are working in different directions. Here I default to European nymphing as my technique of choice. It allows me to present two nymphs to the fish

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