Дослідження темпу росту цьоголіток стерляді та веслоноса в умовах півдня України

Abstract

The paper contains results of the investigation, devoted to the growth rate of sterlet and paddlefish fry, using combined rearing technology and pond stocking with the fry of different average bodymass. Fingerling rearing was conducted on the base of Dniprovsky sturgeon hatchery, in ponds 2 and 3 hectares square in monoculture. Fish stock was had next parameters: sterlet – 85, 119, 128, and 135 mg; paddlefish – 300, 500, and 700mg. The goal of the research is to set up a correlation between the growth rate of sterlet and paddlefish fry and technological and environmental parameters. Water temperature ranged from 21.0 to 27.9°C during the experiment. Dissolved oxygen ranged from 4.6 to 7.6 mg/l. Average phytoplankton biomass during vegetational season was within 8.7 - 13.8 mg/l range, zooplankton – 3.83 - 8.80 g/m3 , zoobenthos – 2.2 - 10.42 g/m2 , which was sufficient for surgeons growth. It was found that increasing average bodymass of sterlet fry during pond stocking from 85 mg to 135 mg and paddlefish – from 300 mg to 700 mg, allows obtaining better outcome results. During standard rearing period, we have managed to rear sterlet fingerlings with average bodymass 3.1 g and paddlefish fingerlings with average bodymass 279 g. Sterlet survival rate was 63.96%, while for paddlefish this parameter equaled 25.4%. Fish productivity in experimental ponds reached 138.6 kg/ha (for sterlet) and 103.6 kg/ha (for paddlefish)