The Friends of Loch Hourn is a well-established community group of residents & people with an interest in regenerating & restoring the ecological & economic sustainability of Loch Hourn. There is a wealth of anecdotal evidence of a significant decline in wild salmon & sea trout populations, as well as large scale mortality of mussel beds & spat, which coincides with the growth of salmon farming in the loch over the last 30 years but a lack of scientific evidence to either prove or disprove the link. This project will develop a detailed hydrographic & biological model of the loch by simulating tides & currents to provide an overview of sea lice dispersal & consequent impact on smolt migration; to map the cumulative interactions of adjacent salmon farms & how lice densities change over time; to quantify the dispersal of sea lice chemicals & their toxic effect on larval stages of lobster, crab, mussel & other crustaceans; to model the discharge of nutrients from fish faeces (especially relevant as Loch Hourn has a slow flush rate so these build up in eddies & backwaters) leading to algal blooms, depleting oxygen & killing marine life. The completed model will be used to challenge expansion of the local fish farm & be shared with other coastal communities in a similar position. It will also provide essential ‘base-line data’ for future plans for Loch Hourn including the restoration of sea-grass meadows & native oyster beds as well as greater community monitoring (using ROV & sports divers) to identify & then protect key areas for juvenile fish & adult migratory routes. This grant is towards the phase 2 costs of the modelling work.