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Non-fish prey in the diet of fish-eating mammals, Eurasian otter (Lutra lutra) and mink (Neovison vison)
Tuzarová, Veronika ; Čech, Martin (advisor) ; Poledníková, Kateřina (referee)
The Eurasian otter (Lutra lutra) is considered, along with the American mink (Neovison vison), a significant fish predator not only in the Czech Republic but also in other regions across Europe. One of the goals of this study is to determine, based on available literature, the types of prey that form the diet of the Eurasian otter and the American mink, specifically focusing on the non-fish component of their food and how the percentage representation of these items changes in the diet of both species depending on habitat and season. Another objective is to verify whether the American mink has a higher proportion of non-fish prey in its diet compared to the Eurasian otter. The processed data describing the diet through spraint analysis in biomass units were divided according to climatic regions, i.e., temperate, Mediterranean, and also based on the type of aquatic environment, i.e., stagnant or flowing water. The results of the study indicate that the American mink consumed, on average, three times more non-fish prey (74 % biomass) throughout the year than the Eurasian otter (24 % biomass). The seasonal variation had the most notable impact on the consumption rate of frogs and birds in the non-fish diet of both predators. According to the analyzed data, both predators especially focused on frogs,...
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