Modelling the influence of flow and other environmental variables on the migration of atlantic salmon (Salmo salar) in a UK chalk stream

• Main Author: Wilding, Nicholas, Arthur
• Format: Thesis
• Language: English
• Published: University of Southampton 2023
• Subjects: Metcalfe; Atlantic salmon; Salmo salar
• Online Access: https://eprints.soton.ac.uk/473644/; https://eprints.soton.ac.uk/473644/1/Mphil_thesis_Wilding.pdf; https://eprints.soton.ac.uk/473644/2/FW_Thesis_award_forms_signature.msg; https://eprints.soton.ac.uk/473644/3/Deposit_thesis_form_NW.docx

The Atlantic salmon (Salmo salar L.) is a species of substantial cultural, economic and ecological importance. Named “Salmo”, meaning ‘leaper’, by the Romans (Stolte, 1981; Sutterby and Greenhalgh, 2005), the fish is synonymous with persistence and power. The unique nature of the species’ anadromous life cycle is perhaps why the Atlantic salmon is so iconic. Juveniles habituate the freshwater environment during their early development, then migrate to the marine environment to feed and grow, before returning to rivers as mature adults to spawn (Netboy, 1958; Jonsson et al., 1991; Aas et al., 2011). Adult migrations upstream have provided societies with sport, commerce and food for centuries (Hendry and Cragg-Hine, 2003; Susdorf et al., 2017), and are the foundation for the vastly popular salmon angling industry. There are estimated to be 843,000 game anglers in the UK, which contribute to the salmon fishery, which across England and Wales, is thought to be worth £10 million per year (Hinkley, 1995; Environment Agency, 2009). Fished salmon have historically provided communities with a commodity for trade, whilst also offering a proteinrich food source (Thorstad et al., 2008). Ecologically, salmon act as an indicator species for the assessment of riverine health (Parrish et al., 1998), and downstream migrating juveniles in particular provide food for a range of predators such as other freshwater fish species, land and aquatic mammals, and native birds (Metcalfe et al., 1987; Jepsen et al., 1998). Evidence for the protection of Atlantic salmon in legislation dates back to the 13th century, largely owing to recognition for its primary value both as a commodity and as a food source (Netboy, 1958). Modern conservation has evolved to protect the species’ cultural and ecological worth, as well as economic benefits. The Atlantic salmon is acknowledged as a ‘priority species’ for conservative action in the UK Biodiversity Action Plan, and is listed in annex II of the European Union’s Habitat Directive (Hampshire ...