Food Differentiation of Juvenile Brown Trout Salmo trutta L. as a Mechanism for Expanding the Food Supply of the Population

Abstract

The feeding habits of brown trout (age 2+ and 3+ years) in the small Orzega River (Lake Onega basin) are analyzed with an autumn decrease in the number of accessible food items. Along with the previously determined mechanisms for compensating for this phenomenon (feeding directly from the bottom and consumption of large items), a sharp increase in the variability of the individual feeding habits of sea trout in October is revealed both by the composition of the contents of its stomachs and by the amount of consumed feed. The food differentiation of individuals makes it possible to expand the food supply of the brown trout population in the river and effectively use the food resources of the small watercourse, which is particularly important during the period of low availability.