Der Nordische Krill Meganyctiphanes norvegica (M. Sars) : Nahrung und ernährungsethologische Aspekte

The feeding biology was investigated of a population of the nordic krill Meganyctiphanes norvegica which inhabits a semi-enclosed deep near the danish island Läsö. The food composition was determined during one year in monthly samples. The analysis of the stomach contents showed a remarkable diversity. Cannibalism is common, Detritus and undigestible matter form a major part of the compounds at all times of the year. The investigation of the feeding appendages gave evidence that the spectrum of food particles fed is determined by the mechanical properties of the fil tering basket. Optical control of the food is not possible because of the insufficient resolution of the eyes. This explanation of the unspecific food requirements was supported by observations on the feeding behavior. The eyes reveal a high sensibility to perceive even very dim light in contrast to their poor resolution of fine details. This feature illustrates the major role of the eyes in the control of vertical migration and orientation. Quantitative aspects of the feeding biology are dealt within the last chapter. The determination of the amount of food contained in the stomachs allowed to quantify the feeding intensity of the nordic krill. A energy budget based on recent findings is presented and its reliability discussed