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Effect of diet and rearing conditions on growth and survival throughout developmental stages of larvae and juveniles of dusky grouper Epinephelus marginatus (Lowe 1834)

Cabaleiro, Santiago, Barreiro, Lucía, Caamaño, Rubén
Aquaculture international 2018 v.26 no.4 pp. 1109-1118
Epinephelus marginatus, Rotifera, animal growth, cannibalism, death, diet, energy efficiency, fluorescent lamps, grouper, juveniles, larvae, metamorphosis, rearing, survival rate, tanks, trapping
Two rearing conditions, tank light-dimensions and diet, were tested in dusky grouper—larvae and juveniles—in order to improve larval rearing techniques for this species. Larvae reared in high-volume and fluorescent tubes showed the highest survival rate at 18 dph (17.67%, 16%). This might be due to a higher depth and less trapping area during surface death in high-volume tanks than in low volume. Besides, a 500-lx evenly distributed light with fluorescent tubes might improve survival rate at early stages rather than illumination with energy-efficient light bulbs (4.68%, 9.64%). Light bulbs created shaded areas with less illumination inducing low larval activity. First feeding was performed with minimum rotifer lorica width of 102 ± 10.2 μm. No mixed diet was supplied. Throughout metamorphosis, stress shock syndrome appeared to be the main cause of mortality. Diet A showed best growth and survival (4.1–7.36%) during this period probably due to its high HUFA content (9.5%). Contrary to what was observed during first stages, groupers showed best performance with lower illumination. Cannibalism was observed during this period in all culture conditions.