Co-Authors:
Spataru, P., Fish and Aquaculture Research Station, Dor, D.N. Hof Hacarmel, Israel
Hepher, B., Fish and Aquaculture Research Station, Dor, D.N. Hof Hacarmel, Israel
Halevy, A., Fish and Aquaculture Research Station, Dor, D.N. Hof Hacarmel, Israel
Abstract:
Qualitative and quantitative analyses were carried out on the intestinal content of 408 carps of age 0 + collected from ponds manured with liquid cowshed manure, with or without the addition of supplementary feed. These analyses were combined with a study of the benthos in the same ponds. Conclusions drawn were that the natural food preferred by this fish species consists of the components of the zoobenthos, especially larvae and pupae of chironomids. When the carp were fed supplementary feed through a demand feeder, the natural food consumed was mainly from the surface layers of the water, such as pupae of chironomids at the last stage of their development, before or during the hatching of the adult, Heteroptera, and also Cladocera, Copepoda and Rotatoria from the zooplankton. The daily addition of liquid cow manure caused harsher environmental conditions in the water, led to a decrease in the number of species of the benthos and of the plankton, and consequently had an influence on the trophic spectrum of the carp. Supplementary feed when available, replaces some of the natural food and it seems that the carp seeks more easily accesible food items. © 1980 Dr. W. Junk b.v. Publishers.