First basis for a sustained juvenile production technology of fat snook Centropomus parallelus Poey

Resumo

A larval, weaning and nursery trial with fat snook Centropomus parallelus Poey was conducted in Santa Catarina, Brazil. Spawning of captive broodstock was induced with 50 µg/kg LHRHa and fertilized eggs (82.7%) were stocked in two 1,800 L tanks at a mean density of 41.3 eggs/L. Larval hatching averaged 92%. Nannochloropsis oculata (Droop) Hibberd was introduced daily from day 1 until day 20 post-hatch (d20ph). Rotifers Brachionus rotundiformis Muller were supplied during the first month and Artemia meta-nauplii from d19ph to d66ph. Weaning was carried out from day 51 to day 66 with a 43.6% protein dry diet, supplied together with Artemia meta-nauplii. An abrupt temperature drop of 5ºC during the night of d26ph began the first mass mortality period, which lasted for 3 weeks. Mortality during weaning and nursery was less than 4%. A total of 10,200 juveniles (52.4 ± 1.4 mm and 1.25 ± 0.06 g) were harvested with a survival of 6.5%, mean final density of 2.8 fish/L and biomass of 3.5 kg/m3. Food conversion rate during nursery was 1.283 and the increase in variance of the size distribution in total length was 7.5%.