Croatian Journal of Fisheries (Dec 1998)
CARP ADVANCED FRY POND WATER OXYGEN AND BOD5 DYNAMICS
Abstract
Changes and dynamics of Oxygen and BOD5 quantity in 3 carp advanced fry ponds of 8-10 ha-1 was examined during 6 growing seasons (from 1990 to 1995). Carp fry was grown semiintensely cultured with 3 days old carp larvae in amount of 200.000 ind ha-1. Oxygen quantity inadvanced fry ponds during growing seasons varied from min. 1.9 mg l-1 to 12.48 mg l-1, and saturation with O2 from min 22% to 142 %. BOD5 varied within the amplitude of min 0.37 mg 02 l-1 to max. 9.93 mg 02 l-1. The average oxygen quantity dissolved in advanced fry ponds water compared to the average oxygen quantity in the inflowing water was 2% to 43% lower. There has been a significant decrease (p<0.05) in August and September, totalling 37%. to 43%. In all the advanced fry ponds there has been a significant increase of BOD5 (p<0.05). Compared to inflow water the average BOD5 increase in advanced fry ponds was 200% to 350%.
