The Chess is well regarded by fishermen for its brown trout (Salmo trutta) populations, as featured in the BBC2 programme The Accidental Angler.
Brown trout require good quality, oxygen-rich water to thrive and successful breeding depends upon a clean gravel bed for winter spawning. You can see trout spawning in the Chess in our YouTube video. The diet of the brown trout includes invertebrates both on the river bed and those flying near the water's surface. A habitat capable of supporting healthy trout will support a lot more wildlife, including invertebrates, birds and mammals.
Brook lamprey (Lampetra planeri) are primitive, jawless fish and are the most widespread of the lamprey species in the UK. Populations have been declining, however, due to habitat loss and pollution. Brook lamprey need clean gravels to spawn, and soft, marginal silt for their ammocoete larvae. Historically, the River Chess had a good population of this fish, but recent sightings have been rare. However, we were delighted to see good numbers of lamprey spawning in March 2012, as you can see in this YouTube video.
The grayling (Thymallus thymallus) is known as the 'Lady of the Stream' and enjoys quick flowing and well-oxygenated water with clean gravel beds. Grayling have silvery sides, with the back being blue to greeny-brown in colour. However, their main distinguishing feature is the large and beautifully coloured dorsal fin.
Grayling generally feed on invertebrates on the stream bottom, but will take hatching flies on the water's surface.
The Bullhead (Cottus gobio) is a much smaller fish, which can be found on the stream bed, holding on to pebbles and rocks by its large pectoral fins. It is often found in fast-flowing, shallow stretches. Also commonly known as the Miller's thumb, the bullhead had a wide, rather flat head with a large mouth.
The Bullhead feeds on bottom-dwelling invertebrates at dusk. View the ARKive entry for this fascinating fish.