Fish

This webpage gives some common, some less common and some rare examples of fish species in the Yorkshire Dales National Park. The species featured here are as follows:

Atlantic Salmon
Brown/Sea Trout
Bullhead
European Eel
Grayling
Lamprey

Atlantic Salmon

The Atlantic salmon (Salmo salar), is present in some of the Dales rivers. It is a migratory fish which travels from the sea to freshwater to spawn. In the UK salmon eggs are laid, fertilised and then covered over in the gravel of the river bottom. The eggs hatch in early spring and then emerge from the gravel in April and May. They then stay in the river for between 1 and 5 years depending on water temperature and the quantity of available food. On the year the young fish leave the river they start to leave in late spring and most will be gone by June. The young fish then travel together to deep sea feeding areas and they stay at sea for 1 to 4 years. When the salmon return to their home rivers to spawn they have to swim against the flow of the river to reach their spawning sites. Once they have spawned most adult fish die. In the Yorkshire Dales National Park Atlantic salmon is present in several rivers and streams including the River Ribble (Ribblesdale), the River Dee (Dentdale), the Clough River (Garsdale) and the River Rawthey near the Howgills. In the national Species and Habitats Review 2007, atlantic salmon was added to the UK list of priority species for biodiversity action.

Brown/Sea Trout

Brown Trout are non-migratory but are thought to be members of the same species as the migratory sea trout. The brown/sea trout (Salmo trutta), is widespread throughout the British Isles and is an indicator of relatively clean water but their populations are currently declining. In the national Species and Habitats Review 2007, Brown trout/sea trout was added to the UK list of priority species for biodiversity action. The colouration of brown trout varies depending on the prevailing conditions. For example, it is said that brown trout in acidic moorland tarns are dark-coloured, whereas brown trout in alkaline rivers in limestone country can be crimson with black spots. Furthermore, a brown trout in a deep pool can often be dark and is capable of lightening its own colouration in a matter of minutes if it moves into the clear shallows. However, generally adult fish are brownish with numerous black and rusty red spots on their upper sides. In the UK this species tends to develope to 30cm long. Brown trout are present in most rivers and streams in the Yorkshire Dales National Park. National Park staff and Dales Volunteers have recently been helping a PhD student who is studying brown trout populations in the Ure catchment with Durham University. Project details are available from the Yorkshire Dales Rivers Trust website linked below.

Bullhead

The Bullhead (Cottus gobio), also known as Miller's thumb is present but not common in most of England and Wales. At a European scale this species is comparatively rare which makes the UK population of European significance. The bullhead is a small bottom-dwelling fish that inhabits rivers, streams and stony lakes, with fast-flowing, clear, shallow water with a hard substrate. They are also said to be found in the headwaters of upland streams. The bullhead is a short-lived species (3-4 years), which matures early and spawns several batches of eggs each year between February and June. It feeds on small invertebrate species such as freshwater shrimps, mayfly nymphs and caddis larvae. Nationally the population is thought to be declining due to the lowering of the water table and changes in drainage due to agricultural and forestry pressures. Due to the European significance of the UK population the bullhead is listed in Annex II of the EC Habitats Directive 92/43/EEC, which has been translated into UK legislation and is known as the Habitat Regulations of 1994. In the Yorkshire Dales National Park, rivers in which the bullhead has been formally recorded include the Wharfe, the Ribble, the Dee (Dentdale), the Clough River (Garsdale), the Swale and the Ure catchment. In 2007 bullhead was found frequently in the Ure catchment as part of a PhD project concerning brown trout.

European Eel

The European eel (Anguilla anguilla), is present but not common throughout much of the UK. Eels are born near the Sargasso Sea (in the Bermuda triangle between the West Indies and the Azores), and then travel on the Gulf Stream to arrive in the freshwater rivers of Europe in early summer. Once in Europe they live in our shallow rivers and lakes where they feed on invertebrates. Eels can live in the freshwater habitat for up to 50 years and can measure 60-80cm long before journeying back to the Sargasso to mate and then die. The European population of eels has declined dramatically over the last 20 years. It is thought that one of the main causes of this decline may be the slowing of the Gulf Stream, with the result that young eels drifting on this current from the Sargasso Sea are dying before they reach Europe. Climate change may be causing the Gulf Stream current to slow. According to the Environment Agency the eel fishery is the most valuable commercial inland fishery in England and Wales, providing significant benefits to the rural economy. In response to the declining national eel stocks the Environment Agency launched the National Eel Management Strategy in 2001. In the Yorkshire Dales National Park, rivers in which the European eel has been formally recorded include the Ribble with occasional records in the Wharfe, the Dee (Dentdale) and the Clough (Garsdale). The most recent records found date back to 1998 and so at present it is unclear whether this species is still present in the National Park.

Grayling

The grayling (Thymallus thymallus), has a patchy distribution in England, Wales and Scotland and its low population has been causing national concerns. In 2003 the Environment Agency launched a National Trout & Grayling Fisheries Strategy. The aims of this ongoing strategy include conserving and improving wild stocks of grayling. In the Yorkshire Dales National Park, rivers in which the grayling has been formally recorded include the Wharfe, The Ure and the Bain (Wensleydale). However only a small number of records were found and the most recent records date back to the year 2000. Therefore, at present it is unknown whether this species is still present within the National Park.

Lamprey

There are three species of Lamprey which live in the rivers and streams of the UK. These three species are river lamprey (Lampetra fluviatilis), brook lamprey (Lampetra planeri) and sea lamprey (Petromyzon marinus). Lampreys are eel-shaped jawless fishes. They feed on other fish and aquatic vertebrates by fixing themselves by their round mouth to their host and boring into the hosts flesh with their toothed tongue. Lampreys breed in fresh water, and the young live as larvae for about five years before migrating to the sea. The UK populations of these three species are important at a European level. As a result all three species are listed under Annex II of the EC Habitats Directive, which has been translated into UK legislation and is known as the Habitat Regulations of 1994. It is thought that it is the river lamprey or brook lamprey that lives in the Yorkshire Dales National Park but we can not be certain, because the formal records found were not species specific. The most recent records found date back to the year 1997. Therefore, at present it is unknown whether this species is still present within the National Park. In the national Species and Habitats Review 2007, river and sea lamprey were added to the UK list of priority species for biodiversity action.

Websites:

Environment Agency (opens in new window)

Yorkshire Dales Rivers Trust (opens in new window)