УДК 639.371.2 (477.7)

A. Bilyk
N. Hrudko
I. Sherman

The goal of this research is to define influence of fishstock fry while rearing sterlet and paddlefish fingerlings in terms of Southern Ukraine.

Sturgeons fingerlings rearing was provided according to combined technology on the Dniprovsky sturgeon fish facility. Research was conducted in ponds with 2 and 3 ha square.

Paper represents rearing results and biological characteristic of sterlet (Acipenser ruthenus L.) and paddlefish (Polyodon spathula W.) fingerlings.

We monitored water physical and chemical parameters, foodbase (both qualitative and quantitative analysis of phytoplankton, zooplankton, zoobenthos).  Environmental conditions in experimental ponds were close to recommended for sturgeons cultivation. Season averages in separate ponds were in next ranges: water temperature ––24,0–26,3°С; dissolved oxygen –– 6,2–7,0 mgО₂/dm³; рН – 7,3–7,5; phytoplankton biomass –– 8,7-13,8 mg/dm³; zooplankton biomass –– 3,83– 8,80 g/m³; zoobenthos biomass –– 2,20–10,42 g/m².

Gastrointestinal tract content analysis demonstrated that the most abundant in sterlet food lump was zooplankton species (Daphnia) and Chironomidae, for paddlefish –– Daphnia.

Obtained data allows us to state that stocking ponds with larva having average individual bodymass (AIB) as much as 135mg leads to receiving sterlet fingerlings with AIB 2.7-3.5g, survival rate – 62.1-65.8%, fish productivity – 138.6 kg/ha. Maximum results for paddlefish such as survival rate (29.3%), AIB (278g) and fish productivity (120.8 kg/ha) were obtained while stocking ponds with 800 mg larva.

We defined correlation between fishstock fry average bodymass and resulting bodymass, survival rate, fish productivity. This correlation was described with polynomial equation (Determination coefficient was 0,7801–0,9465 for sterlet and 0,8506–0,9597 – for paddlefish).

Obtained results complement main specification for starlet and paddlefish fingerlings rearing technologies in terms of Southern Ukraine according to demand of modern aquaculture.

Keywords: sterlet, paddlefish, fingerlings, fry, foodbase, survival rate, average individual bodymass, fish productivity.