Between 1995 and 2003, otter surveys were conducted on 11 islands off the north west coast of Scotland. These located holts in a 100-metre-wide strip along the coasts of these islands. The information was then used to calculate the total number of holts for each island, and from that the adult otter population for each island was calculated using the models based on studies in Skye and Shetland. The diet of marine-foraging otters was assessed from five of these islands using spraint analysis, and was compared with the diet of otters from other coastal areas in Scotland. With the exception of the free-swimming saithe, the diet was dominated by small benthic fish, with the five key prey species being viviparous blenny, five-bearded rockling, butterfish, sea scorpion, and saithe.