A decade of studies at Loch Fleet, Galloway (Scotland): A catchment liming project and restoration of a brown trout fishery

Loch Fleet is a small upland lake in the hills of Galloway in southwest Scotland. In the 1970s the waters of the loch became more acidic and a brown trout fishery failed. This account summarises an experimental project, the "Loch Fleet Project" initiated in 1984, designed to reverse acidification of the loch by liming parts of the catchment. Liming about 40% of the catchment in 1986 and 1987 raised the pH and calcium levels, and reduced toxic aluminium concentrations. The improved conditions had been maintained up to 1994, but water in the loch, and its principal inflow stream, is now falling close to the desired threshold of quality. After liming, restocking with local strains of trout in 1987 was successful, and a self-recruiting population became established within 2 years. Recruitment is highly variable, however, and was attributed to severe spring conditions and the limited spawning capacity of the nursery stream, rather than to water quality

A decade of studies at Loch Fleet, Galloway (Scotland): a catchment liming project and restoration of a brown trout fishery

Loch Fleet is a small upland lake in the hills of Galloway, in southwestScotland (see photograph on the front cover of this issue, and Figs 1-3).The waters of the loch became more acidic in the 1970s and a browntrout fishery in the loch had failed. The following account, intended forthe general reader, summarises an experimental project designed toreverse acidification of the loch by liming parts of the catchment, and wedescribe briefly the changes that have occurred in limed soils on thecatchment, water chemistry in streams supplying the loch, the reestablishmentof the trout fishery, and some associated changes interrestrial and wetland ecosystems on the catchment