WHEN rivers rise after heavy rain, it’s hard to imagine how fish cope with such a rapid influx of what is often dirty water.
Their first instinct is survival, and different species are better adapted to dealing with the conditions than others.
Although a lot depends on the temperature of the water and the amount of debris coming down the flow, as a general rule as the river starts to rise, the chub will go off the feed quite quickly. In contrast, the barbel will start to feed more heavily.
At the height of the flood, the barbel continue to feed well, but contrary to popular belief, they will spend a fair amount of their time close to the bank, saving energy for when they need to re-enter the flow to feed.
Once the river has fined down and the colour has begun to drop out, the chub will come more on the feed, while barbel appetites will drop off slightly.
Finally, once the river is back to its normal levels, the chub are usually the first species to start to feed ravenously, with far fewer barbel being caught.
Although fish such as roach, dace and bream will push into areas of slack water in big floods, as soon as conditions become tolerable they’ll push back out and look for food again. That’s why the crease area between the flows is one of the best places to target. Most fish will gather here, because it’s where food items accumulate.
The big ‘spanner in the works’ with all of this is snowmelt, which is the kiss of death for fishing and can cause the biggest floods of all. If this happens, you’re better off staying at home for a few days until the fish have acclimatised to the shock and water levels have started to drop again!
Barbel are well equipped for holding station tight to the bottom, and will often feed hard if the water is coloured and warm (above 430F).
Very few other species are able to deal with such conditions, and won’t be found inhabiting this area.
Where the main flow meets slower water is a productive area to target chub. They often sit just on the slack side, waiting to dash out and intercept food items such as worms that may have been washed into the river. Roach and dace will also often sit on this borderline area.
Acting as a refuge from turbulent water, slacks are free of debris being carried downstream. As well as chub, roach and dace, bream can be found sheltering here, and can feed well in warm coloured water during winter.
Predators like perch and pike, which feed primarily by sight, will tuck themselves up right underneath any available cover that’s out of the main flow. Undercut banks and inlets/tributaries also act as a refuge for these species.