Whilst flow is often seen simplistically as a measurable and manageable variable in rivers, the habitat value of flow is delivered by interactions with channel morphology and substrate. The resulting hydromorphology impacts on all salmonid life stages; its proper understanding requires integration between the sciences of hydrology/hydraulics, geomorphology and freshwater ecology, but this integration is scarce. This study desc...

Flow regulation is a major constraint on fish populations in many river systems. Current scientific understanding of the direct and indirect influence of hydrology on salmonids between spawning and emergence is reviewed and used to identify key knowledge gaps. The review emphasises difficulties in linking ecological response to physical process understanding and, conversely, the difficulties in applying detailed process unders...

This study investigated the effects of diurnal temperature variability (>7° C) on the growth of 1+ year Atlantic salmon Salmo salar . Experimental manipulation of water temperature was used to simulate: (1) constant and (2) naturally varying thermal regimes with similar daily mean values. Data from two replicates of four treatments (two thermal and two feeding regimes) were collected over 6 months corresponding to the main spr...

The temperatures of stream water and hyporheic water were monitored in spawning areas of an upland stream (Girnock Burn) and a degraded lowland stream (Newmills Burn). Both streams are located in North‐east Scotland and are spawning streams for Atlantic salmon, Salmo salar L., and brown trout, S. trutta L. Monitoring between the spawning and hatching of ova revealed significant differences in the thermal regimes of the two sit...

Kielder Reservoir and the Kielder water transfer scheme have been operational since the early 1980s. The hydro‐ecological changes that occur in the River North Tyne and the River Wear as a result of Kielder operations are highlighted and release policy changes designed to minimize impacts on salmonid fish are described. The Kielder Reservoir release regime results in sudden and marked changes in flow in the North Tyne. These c...

The Girnock Burn, a tributary of the River Dee, has been used as a monitoring site for Atlantic salmon, Salmo salar L., populations since 1966. The burn drains a catchment of 30 km 2 and is a third order stream at the catchment outlet; its width ranges from 1 m in the headwaters to around 15 m in its lower reaches. During the period 1966–1996, the mean number of fish (average lengths; males = 0.64 m and females = 0.68 m) enter...