The machair lochs lie on the west side of South Uist, nestling below the mountains of the east and behind the Atlantic sand dunes to the west.
Machair land is limited to small areas of land on the west coasts of Scotland and Ireland and the soil has a high shell content of up to 90% crushed shell. The lochs that sit on the machair are alkaline and sustain a rich food supply for the salmon, sea trout and brown trout that inhabit them.
A network of drainage ditches, rivers and burns connects the lochs to the sea and, though the system was built to protect the low lying grazing land from flooding, it allows the migratory fish to reach a greater than expected number of lochs.
Their close proximity to the sea makes many of the South Uist lochs brackish and this adds to the unique experience of machair fishing.
Though popular with anglers for the salmon and sea trout that grow up to 10lbs in weight, the lochs also yield brown trout at weights of up to 5lbs. However, average sizes for fish caught are closer to half the weight of the largest the lochs yield each year.