Skip to main content


Title: Estuarial migration of Atlantic salmon in the river Dee (North Wales)
Author: W.K. Purvis
Author: C.R. Crundwell
Author: D. Harvey
Author: B.R. Wilson
Document Type: Monograph
The main objectives of this NRA report are: to describe the migration of adult Atlantic Salmon (Salmo salar L.) through the Dee estuary and to relate behaviour to environmental factors; river flow, water quality and tidal regime; and to assess the impact of the tidally influenced weir at Chester on salmon migration. There is concern that proposed barrages, whether for power generation (eg Severn Estuary) or amenity (eg Usk estuary) will impact upon populations of some fish species which utilise estuaries. Atlantic salmon are not tolerant of conditions of poor water quality and are therefore of considerable value as indicators of the health of estuaries. Furthermore, they make substantial contributions to many economically important recreational fisheries. Salmon migrate through estuaries at least twice during their life cycle which puts them at risk from developments within the estuarine environment. However, the behaviour of salmon in estuaries, their responses to estuarine obstructions and the effectiveness and efficiency of fish passes are all poorly understood. The main concerns relating to power generating schemes include the effects of physical obstruction to migration, altered tidal regimes, possible reductions in impoundment water quality and damage resulting from contact with the turbines.
Publisher: National Rivers Authority
Publication Date: 1994
Publication Place: Buckley
Subject Keywords: Salmon fisheriesEstuarine fisheriesMigrationEnvironmental factorsWater qualityFlow rateChemical composition
Geographic Keywords: Dee (Tidal) catchmentDee (Wales)
Taxonomic Keywords: Salmo salar
Extent: 53; + figures
Total file downloads: 24

Download PDF    Display PDF in separate tab