Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8493269 | Aquaculture | 2018 | 6 Pages |
Abstract
The natural spawning and scaling-up the larval rearing of yellowtail snapper (Ocyurus chrysurus) are described. We obtained fertilized eggs via the volitional spawning of broodstock acclimated for two years in two 12-m3 tanks. Of the eggs collected 10 to 14â¯h after spawning, 87.3% were floating, and 90% of these were transparent and presented a live embryo (egg diameter of 824â¯Â±â¯77â¯Î¼m and oil droplet diameter of 137â¯Â±â¯14â¯Î¼m). The incubation period was 18â¯h at 27â¯Â°C and 38â¯gâ¯lâ1 salinity. The average normal larvae hatching rate was 88.3â¯Â±â¯3.3%, and the notochord length of the newly hatched larvae was 2.5â¯Â±â¯0.5â¯mm. Larval survival at 48-h post-hatching was 48.1â¯Â±â¯3.7%. The initial mean stocking density in the 2500â¯l rearing tanks was 206.3â¯Â±â¯24.5â¯floatingâ¯eggsâ¯lâ1, which resulted in 99â¯Â±â¯43â¯larvaeâ¯lâ1 per tank. A total of 261,736 juveniles were harvested at a mean of 50â¯Â±â¯3â¯days post-hatching (dph) from ten 4.5-m3 cylindrical fibreglass tanks, which presented a mean of 26,174â¯Â±â¯3211 juveniles per tank (5.8â¯Â±â¯0.7â¯juvenilesâ¯lâ1). The mean survival in the ten tanks was 7.0â¯Â±â¯1.4% from the time of hatching and 15.0â¯Â±â¯2.9% as of the first feeding (48-h post-hatching). Two critical periods with high larval mortality occurred during rearing: between 4 and 7â¯dph and during the third and fourth weeks (20-28â¯dph). At harvest, the mean total length (TL) was 3.8â¯Â±â¯0.2â¯cm (range: 2.9-5.4â¯cm) and the mean total weight was 0.9â¯Â±â¯0.2â¯g (range: 0.3-2.1â¯g). Larval growth increased from a mean of 0.24â¯mmâ¯dayâ1 during the first 14â¯dph (specific growth rate (SGR) of 6.7%â¯dayâ1) to a mean of 1.73â¯mmâ¯dayâ1 (SGR of 9.6%â¯dayâ1) in the subsequent 21 rearing days. The mean final biomass was 4.9â¯Â±â¯1.3â¯kgâ¯mâ3. Finally, the results and current and future larval rearing practices for this species are discussed.
Keywords
Related Topics
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Agricultural and Biological Sciences
Aquatic Science
Authors
Irma Gutiérrez-Sigeros, Leonardo Ibarra-Castro, Luis Alvarez-Lajonchère, Adolfo Sanchez-Zamora,