Developing a method to investigate infestation pressure from sea lice on migratory salmonids utilising towed & static sentinel cages

A number of studies have linked the presence of fish farms to sea lice in the environment (e.g. Harte et al 2017) and infestations of wild salmonids (Middlemas et al. 2010 Vollset et al. 2016a) and subsequent population dynamics in marine aquaculture areas (Vollestad et al. 2009; Vollset et al. 2016a). Although there are studies looking at the effect of migration behaviour on mortality (e.g. Vollset et al. 2016b), no study has ever been carried out to design and deploy equipment to measure the specific infestation pressure salmon smolts may experience from sea lice as they enter the marine environment and migrate down a sea loch towards the open sea in a region containing Atlantic salmon aquaculture.