Effects of short-time

The effect of short-time Artemia spp. feeding on growth performance and cumulative survival rate of barbel (Barbus barbus) larvae were studied under controlled aquaria conditions during the 21-day larval period. Three different diets (presenting reduced Artemia feeding) were tested for first exogenous nutrition of larvae (since 13 days post hatch): (1) artificial feed (Asta); (2) Artemia nauplii for 7 days followed by artificial feed; (3) Artemia nauplii for 14 days followed by artificial feed. The longer period of live food statistically improved growth of larvae (W = 174 ± 20 mg and SGR = 14.5 ± 0.5% d−1). The artificial dry food Asta without the addition of Artemia nauplii caused statistically decreased growth (W= 135 ± 22 mg and SGR= 13.1 ± 0.7% d−1). However, the growth of larvae with the short period of Artemia nauplii (W = 153 ± 25 mg and SGR = 13.8 ± 0.7% d−1) did not differ compared to either group. All used feeding diets did not have a significant effect on the cumulative survival rate of larvae ranging from 73 ± 1% to 74 ± 1% at the end of the larval rearing period. The effects of the rearing environment on growth performance and survival rate of juveniles were tested under intensive controlled conditions in aquaria and troughs for 84 days following the larval period (from 34 to 118 dph). The environment of the troughs caused significantly decreased growth (W = 2079 ± 433 mg and SGR = 3.1 ± 0.05% d−1) of juveniles compared to ones reared in aquaria (W = 3236 ± 264 mg and SGR = 3.6 ± 0.1% d−1) at the end of the juvenile rearing period. Nevertheless, rearing environment did not have a significant influence on the cumulative survival rate of barbels (SC = 90 ± 4% and 81 ± 3% in aquaria and troughs, respectively).