Growth of juvenile Siberian sturgeon (Acipenser baerii) fed two types of pelleted feed under trough farming conditions

At the end of the growing season 1996 (29 August-19 September), the experimental culture of 116 juvenile specimens of Siberian sturgeon (Acipenser baerii), imported in the form of fertilized eggs to the Czech Republic from Russia in February 1996, was performed in the Novy Dvur Fish Hatchery (Pohorelice Pond Fisheries, A.S.), using farming troughs. The initial rearing of fry was carried out in the Mydlovary Fish Hatchery (Hluboka n. Vltavou, Pond Fisheries, A.S.). In our experimental rearing of Siberian sturgeon in troughs at low natural water temperatures and fed two types of dry pelleted food of the firm ALMA, the following fundamental growth and production parameters were assessed and analysed: daily body length and weight increments (D.I.), specific growth ratio (SGR), daily feeding ratio (DFR), food conversion ratio (FCR), Fulton's factor of weight condition (FWC), 1/FCR and FCR/SGR. In the first experimental group of sturgeon, feed ALMA 7630 (Forellenfutter 40), and in the second group, feed ALMA 6285 (Karpfen futter 40), were used. The type of the food used, and the successive water temperature decline from 18.8 degrees C to 11.2 degrees C had no significant effect on the length growth rate, but these factors were influenced moderately by the intensity of weight growth rate and food conversion. The growth rate was affected markedly by the feeding method. When using the daily feeding doses (1.46-2.10% of the fish weight) in two portions during a day, the intensive growth rate in the first and second experimental groups of sturgeons was characterized by the following parameters: D.I. 0.7083 and 0.7350 mm, SLGR 0.1832% and 0.2027%, SWGR 1.378% and 1.230%, FWC 0.375 and 0.363, FCR 1.40 and 1.70, 1/FCR 0.52 and 0.64, FCR/SWGR 1.36 and 1.62, respectively. When using the daily feeding dose in a single portion within two days, the intensive length growth rate was continued in a similar intensity like it was in the previous case, but the weight growth rate stopped and the weight condition was dropping successively. In the present study, moreover, the results of the length-weight relationship analysis and the values of regression coefficients of the correlations between TL, FL and SL are presented. Mortality of the sturgeons reared (TL = 370.5-406.3 mm, w = 177.7-239.2 g) was zero during the whole experiment. Tank rearing of Siberian sturgeon specimens of comparable size under similar feeding and temperature conditions of the environment, carried out in the Institute of Landscape Ecology AS CR in Brno, in 1995, was more effective as to the values of growth rate and food conversion. Due to its biological properties, Siberian sturgeon is an extraordinarily suitable species for aquaculture and pond rearing in the Czech Republic.