Izvorni znanstveni lanak THE INFLUENCE OF DIFFERENT FOOD ON THE PRODUCTION OF MARKET CARP (Cyprinus carpio L.) Debeljak, Lj. Turk, M. Fa ai , K. Sotji , B. Puni tekst (Hrvatski) Str. 83 - 94 (pdf, 2.21 MB) downloads: 471 Sa etak This research was carried out on 8 experimental fish-pounds with individual sizes of 0,1 ha-1 on fish farm Dragani i during 1990 culturing season. Carp was reared under conditions of polyculture with total stock density 3250 ind × ha-1. (77 % carp, 2500 ind × ha-1 ; 23% -- 250 ind × ha-1 each species of herbivorous fish – silver carp, bighead, grass carp). The influence of fertilization and different feeding of fish was researched through these parameters: yield and increment of fish, individual weight, losses, food conversion, Fultons and Clark’s coefficient of carp. The hydrochemical conditions in individual pounds where researched too (tabl 2). The total increment of fish was 703 ind × ha-1 (I variant, without fertilization, feeding of carp with cereals), 1302 ind × ha-1 (variant II, fertilization, 500 kg × ha-1 NPK 17: 8: 9, feeding with cereals) and 2537 kg × ha-1 (variant III, without fertilization, feeding carp with pellets containing 20% protein of animal origin). The increment of carps was 611.4; 897.8 and 1923.5 kg × ha-1 resp. The results of production are shown on tables 3, 4 and 5. The losses of carp were similar in all variants of fish-pounds (tabl. 4). The average individual weight of carp was 30% bigger in the fish pond with fertilization, and 154% in fish pond with feeding carp with pellets containing 20% protein of animal origin in compare to control variant 1. Food conversion was lower for 26% in the variant which was fertilized, and for 13% in the variant fed with protein pellets, in compare to control variant l. The Fulton's and Clark's condition coefficient of carp was similar in all experimental ponds except in the variant III. In this variant the Fulton's condition coefficient was significantly better (P The presence of herbivorous fishes in this polyculture enlarged the total increment of fishes for 92 kg'ha-1 (variant I), 404 kg'ha-1 (variant II) and 650 kg'ha-1 (variant II!), without an inhibitory effect on the growth rate of carp.