River Usk/ Afon Wysg

General site character

• Tidal rivers, Estuaries, Mud flats, Sand flats, Lagoons (including saltwork basins) (26.8%)
  
• Salt marshes, Salt pastures, Salt steppes (4.5%)
  
• Inland water bodies (Standing water, Running water) (37.9%)
  
• Bogs, Marshes, Water fringed vegetation, Fens (3.8%)
  
• Heath, Scrub, Maquis and Garrigue, Phygrana (3.4%)
  
• Dry grassland, Steppes (8%)
  
• Humid grassland, Mesophile grassland (1.4%)
  
• Improved grassland (2%)
  
• Broad-leaved deciduous woodland (10.1%)
  
• Other land (including Towns, Villages, Roads, Waste places, Mines, Industrial sites) (2.1%)
  

Annex I habitats that are a primary reason for selection of this site

• Not Applicable

Annex I habitats present as a qualifying feature, but not a primary reason for selection of this site

• 3260 Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation

Annex II species that are a primary reason for selection of this site

• 1095 Sea lamprey Petromyzon marinus

  The Usk is a medium-sized catchment in south Wales, important for its population of sea lamprey Petromyzon marinus. Survey of juveniles and observation of spawning adults indicates that this species is mainly restricted to the lower reaches of the catchment. The site supports a range of Annex II fish species.

• 1096 Brook lamprey Lampetra planeri

  The Usk in south Wales supports a healthy population of brook lamprey Lampetra planeri and is considered to provide exceptionally good quality habitat likely to ensure the continued survival of the species in this part of the UK.

• 1099 River lamprey Lampetra fluviatilis

  The Usk in south Wales supports a healthy population of river lamprey Lampetra fluviatilis and is considered to provide exceptionally good quality habitat likely to ensure the continued survival of the species in this part of the UK. The river also supports important populations of 1096 Brook lamprey Lampetra planeri, for which it is also selected.

• 1103 Twaite shad Alosa fallax

  The River Usk is one of the largest rivers in south Wales, and twaite shad Alosa fallax has long been known to spawn there. The Usk is one of only four sites in the UK where a known breeding population of twaite shad occurs (the Rivers Wye and Tywi are other SAC sites). Water quality and quantity are considered favourable for this species. The main channel is largely unmodified and a variety of aquatic habitats are present, including good quality spawning gravels and deep pools used for cover by adults and fry. However, Trostrey and Rhadyr Weirs may be a barrier to shad migration under low flow conditions.

• 1106 Atlantic salmon Salmo salar

  The river Usk is a river famous for its salmon Salmo salar, with a high proportion (c. 30–40%) of multi sea winter fish recorded in the rod catch. In 1999 the Usk had highest estimated egg deposition of any British river south of Cumbria, and was one of the few rivers in England and Wales to exceed its spawning target for salmon. The Usk has a mixed catchment with a largely unmodified river channel, no significant obstructions to salmon migration, good quality spawning gravels and a diversity of habitats providing excellent habitat for salmon parr. The most important tributaries for salmon spawning are included within the site boundary.

• 1163 Bullhead Cottus gobio

  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.

• 1355 Otter Lutra lutra

  The River Usk is an important site for otters Lutra lutra in Wales. They are believed to be using most parts of the main river, from Newport upstream, and in recent years signs of otters have increased. In 1991 an expansion upstream of known otter ranges was recorded on several tributaries, including the Honddu, Senni and Crai. The upper Usk may have acted as a ‘refuge’ during the decline of the 1950s, and had subsequently acted as a ‘source’ population for recolonisation of south-east Wales.

Annex II species present as a qualifying feature, but not a primary reason for site selection

• 1102 Allis shad Alosa alosa