An investigation of the impact of redd washout, fine sediment inflitration and variations in water chemistry during egg incubation on juvenile production of Atlantic salmon (Salmo salar L.)

MacDonald, Alexander (2007). An investigation of the impact of redd washout, fine sediment inflitration and variations in water chemistry during egg incubation on juvenile production of Atlantic salmon (Salmo salar L.). PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000fa27

Abstract

The River Sligachan on the Isle of Skye is a west coast river system with a declining adult salmon stock as evidenced through seventy years of angling records. To our knowledge there is no published literature on the aquatic ecology of this river. This key objective of this work was to establish if current redd washout and variations in water chemistry, during the spawning season through to emergence of alevin, is responsible for apparent reductions in juvenile Atlantic salmon, thereby lowering adult populations returning to the River Sligachan, on the Isle of Skye. To pursue this goal a seasonal study of the River Sligachan and its catchment were undertaken: variables measured included precipitation, water chemistry, temperature, fine sediment infiltration, flow rates / flow profiles and artificial redd washout. A river corridor survey (with integrated management plan), and a river channel geology / bed material abundance survey, provided additional information to the vegetative and physical structure of the River Sligachan relating to the wider and chemical characteristics of the river catchment.