Abstract
The aim of the study was to optimize burbot juveniles rearing in recirculating aquaculture system. In experiment 1 (17 °C, photoperiod 24L:0D), the fish (initial: body weight [W] = 15.36 ± 3.72 g, standard length [SL] = 12.48 ± 1.09 cm) were divided into four groups (I, II, III and IV). Different feeding levels were applied: 1, 2, 3 and 4 % of biomass daily (counted based on dry feed weight). The feed conversion ratio (FCR) and specific growth rate (SGR) were recorded. In experiment 2 (17 °C, feeding level of 2 % of biomass day−1), fish (W = 5.24 ± 2.43 g and SL = 8.54 ± 1.24 cm) were divided into two groups where different light conditions were applied (I: 24 h light [1,800 lx] and II: 24 h darkness [4 lx]). In experiment 1, the highest SGR was recorded in group II (1.93 % day−1), whereas the lowest SGR (1.27 % day−1) and final W (P 0.05). The feed consumption in group I reached 100 %, in group II, it was 71.3 % (P 0.05; W between 23.33–23.35 g; P > 0.05). The results from experiment 1 indicate that the feeding 2 % of biomass day−1 was the most efficient. Also, it was proven, for the first time, that there was no effect of using different constant light conditions.
Highlights
Burbot (Lota lota L.) is the only representative of the Gadidae family that inhabits freshwater reservoirs of the Holarctic ecozone (Nelson 1994)
feed conversion ratio (FCR) was on a similar level (0.68–0.70) (Table 1)
The lowest (P \ 0.05) feed consumption was recorded in the group III (39.26 %) and group IV (26.93 %) (Table 1)
Summary
Burbot (Lota lota L.) is the only representative of the Gadidae family that inhabits freshwater reservoirs of the Holarctic ecozone (Nelson 1994) This species is endangered in almost all of its habitats (Wolnicki 2001), and it has become important candidates selected for intensive aquaculture (Wocher et al 2011a, b). It has become a focus of extensive scientific ventures aimed at elaborating intensive methods of burbot production both for restocking purposes and aquaculture (Wolnicki 2001; Z_ arski et al 2009; Jensen et al 2011; Trabelsi et al 2011). The advantage of RAS is the possibility to control physical and chemical water parameters such as temperature, pH, oxygen content as well as to monitor the health status of fish and to accurately determine feed rations (Blancheton 2000; Remen et al 2008; Z_ arski et al 2008, 2010a)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
