Evaluation of the breeding potential of Mugil cf hospes and Mugil liza juveniles in a biofloc system
The use of dry diets in the larviculture of marine fish is still a challenge, with the weaning period being a critical stage of production. This work aimed to evaluate the effect of the stage of development in which juveniles of Paralichthys orbignyanus started to eat feed on their survival and growth. Three ages were tested that corresponded to the periods before (D23), during (D26) and after (D29) larvae laying, after a co-feeding period of five days, when the larvae received Artemia and feed nauplii (INVE, 58 % protein, 150- 300 μm). A control group remained fed with Artemia nauplii. The treatments were performed with four replications with 200 individuals in each tank. The tanks remained in a thermostated bath (25.5 ± 0.5oC), with salinity between 30 and 34 ‰ and 24 hours of light.At 40 days of life, survival was significantly affected by treatments. The survival of juveniles in treatment D29 (54 ± 13%) was equal to the survival of treatments D26 (35 ± 17) and D23 (39 ± 14), and the control group (82 ± 15%), which was different from the others. The juveniles in the control group were significantly larger in weight and length (70 ± 30mg and 18 ± 3mm) than the juveniles in the other treatments. Despite the greater survival and growth of sole fed with Artemia, it was demonstrated that the larvae of P. orbignyanus accept inert food before laying, between 18 and 23 dae. Among the groups that performed the weaning, the best results were found in the individuals who started the weaning after the settlement.