COULD STERLET (ACIPENSER RUTHENUS) AS POLYCULTURE SPECIES TO POSITIVELY INFLUENCE THE PIKEPERCH (SANDER LUCIOPERCA) FARMING IN RECIRCULATING AQUACULTURE SYSTEMS?

The pikeperch Arming in recirculating aquaculture systems (RAS) has a relatively short history, and many ideas for production improvement in this species recently emerged The polyculture is one of these. The aim of this study is to evaluate if sterlet as polyculture species reared in RAS with pikeperch could have a beneficial impact on tank's bioproductivity and growth dynamic of the juvenile pikeperch. One control (monoculture) (C) and two polyculture variants have been established in duplicate: 1335 pikeperch, 45 days old/m(3) with 10% (VI), and 20% (Vi) sterlet. The experiment has been carried out during 35 days into al:MS with 6 tanks (1 m(3)/tank). The fish were fed in all tanks with dry food 10% of pikeperch biomass in each tank daily, assuring ad libitum feeding. A significant plus offish biomass resulted by valorisation of the pellets unconsumed by the pikeperch. in both experimental variants (V-1, V-2). The pikeperch reared for 35 days in polyculture with 20% sterlet (V-2) had significantly higher body weight than the pikeperch reared with 10% sterlet (V-1) or in monoculture (C).