Prime feeding and reversing currents

Words by:
Barry Grantham
Featured in:
February 2023

The trout will not live just anywhere in a river system. It has a lifestyle based on certain areas.

Trout will want a place to feed, where food will be readily available, and a place to rest and be safe from predators. In the river there will be many such places. Uneven river beds, where the flow of the current has created dips, large rocks, weed beds and bends in the river’s course – these features will affect a trout’s behaviour.

To be a successful trout angler you have to understand the river (or lake) and the trout’s domain. Feeding areas are essential and on rivers like the Eau and Witham there are many such places. With an average depth of one to three feet and some much deeper pools, they are ideal. They also have nice, gravelled bottoms, large stones and rocks and flowing weed beds. This is the perfect environment for aquatic life.

As anglers, therefore, we must look for a spot along the river that is a safe, comfortable place for the trout, and where the current will provide a steady supply of food. A good example of a prime feeding area is an undercut bank flanked with weed or shaded with bankside vegetation. How many times have you, when walking along the banks of a river, seen a large trout dart out from the undercut bank creating a bow wave as it disappears down the river. Other prime areas are the clear gravelled sections of the river surrounded by weeds and overhanging trees.

Now a bit of controversy: it is thought that a fish, when in the river, will be facing into the flow of the river.

Yes, this is true but there are instances when it will be facing the opposite way. The flow of the water can be reversed due to an obstruction, an eddy, or a fallen tree in the water. A weir pool will have a back current, creating an undertow. These will cause the trout to face in the opposite direction to the main flow of the river. If you can find an area like these, you can expect to catch trout – and possibly a very large trout.

To fish an area with an undertow or reverse flow is not easy. You do need a certain amount of casting skill. To present the fly correctly and not scare the fish, you must use what us fly casting instructors call an upstream mend cast. This involves casting a slack line above the fish, the leader and fly can travel with the reversing current or undertow towards the fish. Once this method of fishing is mastered it can be very deadly.

I have discussed prime feeding areas, so let us now look at feeding habits. If you look at the flow of the river, you can get a good idea of the type of aquatic insect that will be present. In a fast flowing shallow stretch of the river it will most likely be the agile darting nymph known as Baetis. These small nymphs will make up a huge part of a trout’s diet. Baetis is a mayfly more commonly referred to as a blue-winged olive (BWO). These nymphs are very common in all rivers and lakes in the UK. In this fast water the trout will have a constant conveyor belt of food. If it looks edible it will take it; if it does not like it, the trout will spit it out.

In a slow moving current, trout can be more selective. They will at times lock on to a particular food. The angler has to present the correct fly the trout is feeding on to be successful. Watching a trout in its prime lie between weeds feeding is fascinating. It moves slowly side to side, goes forwards and drifts backwards. Sometimes it swims a few feet to take its food and you notice its white mouth as it takes a tasty morsel.

would be a shrimp pattern. Shrimp are abundant in most areas of the river system, as well as snails. These patterns are so easy to tie and imitate and make a simple, effective fly for the beginner to attempt. Weight can be added to the artificial fly to enable it to fish those deep pools. A shrimp pattern is perfect for those reverse current situations on the river.

The freshwater shrimp’s life-cycle is rather complex. The male will grab a female and then hold onto her until he decides whether she can produce a lot of eggs. The male will keep hold of his chosen female, this could be for several weeks. The female will then shed her skin and the male will mate with her. The male then lets the female go and she will carry the developing shrimp in a pouch. After about four weeks the young shrimp will swim out of the female’s pouch; a few months later and the young shrimp can also breed. The female can produce up to 50 young shrimp a month. The population of the shrimp soon grows and the trout has a plentiful food source.

perfect imitation if there is an adult insect hatch on the water’s surface. The nymphs are not large, no longer than 10mm – again, an easy nymph to imitate, from a simple pheasant tail to more complex patterns.

that tasty morsel, it can be very selective, so it is important that you choose an imitation that bears a close resemblance in colour and size.

In April’s issue I will be writing about the emerging and adult fly in those prime feeding positions on the river and providing step-by-step instructions on how to tie the flies you will need.

Words: Barry Grantham



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