River Una

The river

The Una forms part of the border between Bosnia and Herzegovina and Croatia and is the finest grayling river in the Balkans. Its defining feature is tufa — calcium carbonate deposited by moss and algae — which builds natural steps and barriers across the riverbed, creating a long series of deep pools separated by small falls. The name is said to come from the old inhabitants' word for 'the only one', and after a day on it, the claim is not unreasonable.

On this river

Fishing the tufa pools

Each tufa barrier holds a pool that is 2 to 4 metres deep and 40 to 80 metres long, with a fast lip at the head and a slow tail. Grayling shoal in the middle, so the working method is a long upstream nymph drift through the centre, then a dry fly at the lip when the hatch is on. Cover it once and move; repeating a drift in flat water scatters the shoal.

Reading the colour of karst water

The Una's colour is a reliable depth gauge: pale turquoise means clear and low, deep emerald means normal, and grey-green means the catchment above has had rain. Fishing the emerald stage right after the colour starts to drop is the best window, because the fish have had a day of low visibility and are feeding confidently.

Night caddis on a Balkan river

In July the Rhyacophila hatch happens after dark and grayling feed on the surface until midnight. Fish a single #12 caddis on a short line, wade carefully because the tufa is slippery, and use a headlamp sparingly — a beam swept across a pool will put the shoal down for the rest of the night.