1163 Bullhead Cottus gobio
Description and ecological characteristics
The bullhead Cottus gobio is a small bottom-living fish that inhabits a variety of rivers, streams and stony lakes. It appears to favour fast-flowing, clear shallow water with a hard substrate (gravel/cobble/pebble) and is frequently found in the headwaters of upland streams. However, it also occurs in lowland situations on softer substrates so long as the water is well-oxygenated and there is sufficient cover. It is not found in badly polluted rivers.
European status and distribution
The bullhead Cottus gobio is widespread and often common in rivers across Europe.
UK status and distribution
Good populations are widely distributed in freshwaters across almost the whole of England and much of Wales, but in Scotland the bullhead Cottus gobio is restricted to the Clyde and Forth catchments, where it is thought to result from an introduction.
Site selection rationale
Sites have been selected to encompass the natural geographical range of the species and to represent the range of ecological situations in which it occurs, e.g. both upland and lowland rivers, and both acidic and base-rich situations. As with other fish species, site selection has been constrained by the lack of comparative population data from many localities. All available information has been scrutinised carefully to identify large populations occurring in suitable high-quality habitat. While the SAC series makes a contribution to securing favourable conservation status for this Annex II species, wider measures are also necessary to support its conservation in the UK.
Afon Teifi/ River Teifi
West Wales and The Valleys
The Teifi represents bullhead Cottus gobio in west Wales. Water quality is generally good, and the diversity of semi-natural habitat and predominance of stony substrates provides excellent bullhead habitat throughout much of the catchment. Environment Agency electrofishing data shows this species to be widespread throughout the system. Bullheads show marked differences in growth and longevity between upland and lowland streams, and the Teifi includes sections representing both types of habitat.
Afonydd Cleddau/ Cleddau Rivers
West Wales and The Valleys
The Cleddau differs from the Teifi system, also in south-west Wales, in its gentler gradients and more meso-eutrophic nature. The generally finer substrates present and more widespread shading means that bullhead Cottus gobio in the Cleddau Rivers are more likely to depend on macrophytes and woody debris for cover, and represent a lowland type population. Electrofishing data indicates that bullhead are very widespread throughout the catchment.
Craven Limestone Complex
Craven represents bullhead Cottus gobio in calcareous, upland becks and streams in the northern part of its range in England. The clean calcareous waters with their stony bottoms support good numbers of bullhead.
Dorset and Somerset, Gloucestershire, Wiltshire and Bristol/Bath area, Hampshire and Isle of Wight
The Avon represents bullhead Cottus gobio in a calcareous, relatively unmodified river in the southern part of its range in England. The River Avon has a mosaic of aquatic habitats that support a diverse fish community. The bullhead is an important component of this community, particularly in the tributaries.
Cornwall and Isles of Scilly
The Camel represents bullhead Cottus gobio in the extreme south-west of its range in England. The river encompasses a range of ecological conditions with both upland and lowland characteristics. The clean, fast-flowing, relatively oligotrophic waters with their stony bottoms are particularly suitable for bullhead, which forms an important part of the total fish biomass.
Cumbria, North Yorkshire, Northumberland and Tyne and Wear
The Eden represents bullhead Cottus gobio in a high-quality, relatively unmodified river in the northern part of its range in England. The presence of extensive areas of gravel and generally good quality water provides good habitat for bullheads, which are widely distributed throughout the system. The tributaries, in particular those flowing over limestone, hold abundant numbers of bullhead.
Hampshire and Isle of Wight
The Itchen is a classic chalk river that supports high densities of bullhead Cottus gobio throughout much of its length. The river provides good water quality, extensive beds of submerged plants that act as a refuge for the species, and coarse sediments that are vital for spawning and juvenile development.
Berkshire, Buckinghamshire and Oxfordshire
The Lambourn represents bullhead Cottus gobio populations inhabiting chalk streams in central southern England. Good water quality, coarse sediments and extensive beds of submerged plants again provide excellent habitat for the species.
Derbyshire and Nottinghamshire, Leicestershire, Rutland and Northamptonshire, Shropshire and Staffordshire
The Mease is an example of bullhead Cottus gobio populations in the rivers of central England. Bed sediments are generally not as coarse as other sites selected for the species, reflecting the nature of many rivers in this geographical area, but are suitable in patches due to the river’s retained sinuosity. The patchy cover from submerged macrophytes is also important for the species.
River Usk/ Afon Wysg
East Wales, West Wales and The Valleys
The Usk represents bullhead Cottus gobio in the southern part of its range in Wales. It is considered to have exceptionally high-quality habitat with good water quality, abundant cover and a variety of aquatic habitats. Bullhead are widespread throughout the Usk system.
River Wye/ Afon Gwy
East Wales, Gloucestershire, Wiltshire and Bristol/Bath area, Herefordshire, Worcestershire and Warwickshire, West Wales and The Valleys
The Wye represents bullhead Cottus gobio in an extensive river system crossing the border between England and Wales. The Wye is one of the most diverse river systems in the UK, with a range of nutrient conditions and aquatic habitats and generally good water quality for fish species. The diversity of habitat types in the Wye means that it is likely to represent most of the habitat conditions in which bullhead occurs in Britain, highlighting the conservation importance of this river.
SACs where this Annex II species is a qualifying feature, but not a primary reason for site selection
- Afon Tywi/ River Tywi West Wales and The Valleys
- Peak District Dales Derbyshire and Nottinghamshire, Shropshire and Staffordshire
- River Axe Devon
- River Dee and Bala Lake/ Afon Dyfrdwy a Llyn Tegid Cheshire, East Wales, Shropshire and Staffordshire, West Wales and The Valleys
- River Derwent North Yorkshire
- River Kent Cumbria
- River Wensum East Anglia
Many designated sites are on private land: the listing of a site in these pages does not imply any right of public access.