Mark Wintle, an angler for thirty-five years, is on a quest to discover and bring to you the magic of fishing. Previously heavily involved with match fishing he now fishes for the sheer fun of it. With an open and enquiring mind, each week Mark will bring to you articles on fishing different rivers, different methods and what makes rivers, and occasionally stillwaters, tick. Add to this a mixed bag of articles on catching big fish, tackle design, angling politics and a few surprises.
Are you stuck in a rut fishing the same swim every week? Do you dare to try something different and see a whole new world of angling open up? Yes? Then read Mark Wintle’s regular weekly column.
PART TWO – WHAT THEY EAT, AND THEIR IMPACT ON FISHERIES
Otters
What Do Otters Eat On The Dorset Stour? The big question that every angler asks is, “what do otters eat?” Clair Rogers, a third year student at Bournemouth University, with lots of help from many volunteers that collect spraints for analysis, has been painstakingly analysing what they eat in the Stour. She doesn’t have much to go on for there are often few clues in the spraints. It has been a case of carefully separating the remains to see if anything identifiable can be found. Not every spraint contains bones, scales or other remains. For fish, she can identify the species from scales, jawbones and vertebrae. Sometimes, bird remains are found, like the foot, believed to be a moorhen’s, shown at the open day. Other foods may leave no evidence at all in the spraint though it may be found on the riverbank. A good example of this is river mussels. These are bitten open and the soft parts eaten leaving the shells with distinctive signs of the otter’s teeth. As you can imagine, the vertebrae of many of the fish are very small though different types of fish have different vertebrae. In some cases the identification is only generic, ie, roach and dace vertebrae are sufficiently similar that they are counted the same but a perch vertebra is identifiably different.
Much of the fish diet is what one would expect; eels, perch (I’ve seen the otter-eaten remains of perch on the Stour), roach and dace. But other fish surprised me; such tiddlers as sticklebacks and minnows. I’ve already mentioned river mussels; they also eat small mammals, crayfish, birds, and in the sea, crabs. Like most animals, the otter takes advantage of suitable and abundant food supplies. A typical food intake for an adult otter is about 2lbs per day.
Otters and Eels At the open day, Hugh Miles asked what the effect of the eel decline is on otters. This decline is thought to be as much as 99% over the last twenty years. The simple answer is that they will rely on other food. As eels are one of their favourite foods l wonder if the rapid decline of the eel population is at least partly contributed to by the gradual re-establishment of otters on many rivers. This must be only a minor factor compared to the major ones such as over-fishing of both elvers and adult eels, possible changes in the Gulf Stream currents, pollution and parasitic infestation. As the otter is protected and being actively encouraged, and the eel is a favourite food for otters, there must be a strong case for stopping all commercial fishing of eels, including elvers, something that will be unpopular with those commercially involved.
The fishing of adult eels includes the use of fyke nets. A fyke net is a fixed net that is supposed to be marked. Each net has a fixed wall type net that leads into the main part that is like a keepnet but with sections, except that as an eel enters each section, there is an inward pointing funnel that makes it difficult for them to escape. All nets must by law be fitted with an otter guard (a plastic grill) on the mouth of the net but many don’t and you can hardly blame the otter for investigating a fyke net that contains eels or other fish. But once the otter is inside, its chances of escape are remote and it drowns. What worsens the situation is that more fyke nets are unlicensed than licensed, and if you’re working an illegal net you hardly care about otter guards, or any fish that get trapped accidentally.
Otters and Big Carp Over the last few decades, many gravel pits, lakes and ponds have been dug, some for the prime purpose of fisheries. As the fundamental requirement for a fishery is water to fill it, many are situated near streams and rivers. Furthermore, many gravel deposits occur in river valleys such as the Avon, Colne and Frome valleys. I’m sure you can think of many more; the Trent, the Darent, the Lea, the Thames valleys. Today, there are hundreds and hundreds of fisheries that are close to rivers and streams, and there are still more being dug. As anglers, we know that many have been developed as carp fisheries. Modern strains of carp grow quickly; fish of five pounds can reach more than thirty pounds in five or six years in the right environment. Stock fish like this might typically cost £ 25 to £ 30 each, yet be worth in excess of £ 2000 once they reach 30lbs or more several years later. We need to be aware of one more characteristic of carp; carp are a warm water fish. In cold weather, with water temperatures of 4
