MACROZOOBENTHOS IN CARP FISH FRY

Kvalitativni i kvantitativni sastav makrozoobentosa i kemizam vode istraživani su u 6 ribnjaka, pojedinačne veličine 8-10 ha-1, na ribnjačarstvu »Donji Miholjac«. Istraživani su ribnjaci bili nasađeni s 200 000 ind•ha-1 trodnevnih ličinki šarana. Mlađ je u tijeku uzgojne sezone prihranjivan životinjskim bjelančevinama. Kvalitativni i kvantitativni sastav makrozoobentosa formirao se uglavnom na račun sistematskih skupina Oligochaeta i Chironomidae. Prosječna količina Oligochaeta varirala je u pojedinim ribnjacima od 119 do 944 ind•m-2 od 2,18 do 14,09 g.m-2, a ličinki Chironomidae od 174 do 1 086 ind•m-2 i od 2,66 do 14,09 g.m-2. Variranje ukupnog makrozoobentosa bilo je unutar amplitude do 28 do 5 805 ind•m-2 i od 0,11 do 73,72 g.m-2. U sredini ljeta utvrđen je nagli pad količine makrozoobentosa u svim ribnjacima (tabl. 1-6).Qualitative and quantitative components of macrozoobenthos was investigated on six fish farms with 8-10 ha-1 each at "Donji Miholjac". The ponds were stocked with 200,000 individuals per ha! of three-day-old carp larvae. The fry were fed with animal protein throughout the culturing season. The qualitative and quabtitative macrozoobenthos components formed mainly due to systematic groups of Oligochaeta and Chironomidae. The average size of Oligohaeta varied in each pond from 119 to 944 individuals per m-2 and from 2.18 to 14.09 g per m-2, and the larvae of Chironomidae from 174 to 1086 ind. per m-2 and from 2.66 to 14.09 g per m-2. Variation s of the total macrozoobenthos was within the amplitude of from 28 to 5805 ind. per m-2 and from 0.11 to 73.72 g. per m-2. In mid summer it was determined that there was a fall in the amount of macrozoobenthos in all fish ponds (Table 6)