THE INFLUENCE OF DIFFERENT KINDS OF FOOD ON THE ABIOTIC WATER PARAMETERS IN THE CULTURE OF CARP FRY

Istraživanja utjecaja različitih krmiva na abiotičke parametre vode provedena su u devet ribnjaka ribnjačarstva Koprivna. U svaki ribnjak nasađena su 1, 3 milijuna ličinaka šarana, a podrašćivanje je trajalo 25 dana. U postupku 1. ličinke i mladunci su hranjeni starterom tvrtke »Boha, a postupku 2. hrana je sastavljena od 50% startera »Boha« i 50% suhoga pivskog kvasca, dok su a postupku 3. mladunci hranjeni isključivo pivskim kvascem. Pokusom je utvrđena interakcija navedenih krmiva i njihova količina na dnevnu i periodičnu fluktuaciju u vodi otopljenog kisika, prozirnost i organska onečišćenost vode. Dnevna i periodična koncentracija otopljenog kisika bila je znatno viša u ribnjacima u kojima su mladunci hranjeni pivskim kvascem. Utvrđena je vrlo izražena korelacija između količine dnevnog obroka, koncentracije otopljenoga kisika, prozirnosti vode i organske onečišćenosti vode. Dnevni obroci hrane veći od 80 kg/ha ne preporučuju se ako nisu mogući protok ili prozračivanje vode.Investigations on the influence of different food on the abiotic parameters of water were carried out in 9 fish ponds on the Koprivna fish farm. 1.3 million carp fry were stocked in each pond, and the growth period lasted for 25 days. In treatment 1, larva and fry were fed with starter food from "Boha", in treatment 2 the food consisted of 50% starter food from "Boha\u27 and 50% dry beer yeast, while in treatment 3 the fry were fed exclusively with beer yeast. The experiment showed the interaction of the mentioned food and their quantities on the daily and periodical fluctuation in water with dissolved oxygen, transparency and organic pollution of the water. The daily and periodical concentration of dissolved oxygen was significantly higher in the fish ponds where the fry were fed with the beer yeast. An expressed correlation was established between the amount of daily food intake, the concentration of dissolved oxygen, the transparency of the water and organic pollution of the water. Daily feedings over 80 kg/ha are not recommended if there is no water flow or additional aeration