Food Habits of the Otter Lutra lutra L. and the Mink Mustela vison Schreber in a Trout Water in Southern Sweden

The feeding habits of otter and mink were studied in a trout water in southern Sweden in 1966-68. 350 otter scats and 122 mink scats, collected from all the seasons, were analysed. The fish fauna was studied by means of electrofishing. The food of the two predators greatly overlapped (60-70% approximately) as they both exploited easily available prey. The otter fed for most of the year almost exclusively on fish (frequency analysis indicated 90.8 % of food). The mink fed not only upon fish but also upon water-fowl and mammals, mainly small rodents (24.4% and 9.5% respectively of food). The corresponding figures for the otter were 5.5 % and 0.2 %. The two predators tended to feed upon fish of different sizes. About 30% of the fish taken by otter exceeded the maximum size of fish