SIX FISH OF FAST STREAMS

It’s a good time of year to watch salmon leaping up our fast-flowing rivers. But what other species are lurking there? Kevin Parr identifies six fast-stream fish

SALMON PARR Salmo salar

The juvenile salmon have a sleek body, forked tail and fingerprint-shaped ‘parr spots’. They remain in freshwater for up to four years before becoming smolts and migrating to the sea.

BROOK LAMPREYLampetra planeri

The brook lamprey spends most of its life in larvae form, buried in the sediment at the bottom of the stream with only its mouth protruding. It changes into adult form to breed, after which it dies.

BROWN TROUT Salmo trutta

Synonymous with well-oxygenated, fast-flowing water, the brown trout is one of our most familiar fish and a favourite quarry for anglers. The buttery flanks are spotted black and red.

BULLHEAD Cottus gobio

Also known as the miller’s thumb due to its gnarled appearance, the bullhead has a large head, wide mouth, tapered body and fan-like pectoral fins. The eggs are guarded by the male until they hatch.

STONE LOACH Barbatula barbatula

The lithe, eel-like stone loach is a small, barbuled fish that rarely exceeds 10cm in length. The flanks and fins are delicately patterned, with lines and spots that help hide its form on the stream bed.

MINNOW Phoxinus phoxinus

Minnows often occur in large numbers, shoaling in slacks and margins where they are targeted by kingfishers and herons. The belly and lower fins of the male turn bright red as it prepares to breed.