Induced spawning and larval rearing of spotted rose snapper, Lutjanus guttatus (Steindachner, 1869), in Estación de Biología Marina, Puntarenas, Costa Rica

Wild spotted rose snapper, Lutjanus guttatus (n = 400, 60-100 g), were captured and grown out in cages during one year (February 2001 to February 2002). When the mature stage was detected by cannula samples, females (n = 9) were induced to spawn with a total dose of 1600 IU of human chorionic gonadotropin (HCG) per kilogram of body weight, given in two injections (56% and 44% of the total dose). Males received only one injection of 200 IU HCG kg(-1) body weight, at the time of the second female injection. The sex ratio (female:male) was 1:2. Mean female body weight was 604.9 +/- 98.8 g (36.4 +/- 2.1 cm). Egg release occurred 9-12 hours after the second injection (latent period), at a temperature of 26.3-28.2 degrees C, salinity of 30-32 parts per thousand,, and oxygen concentration of 5.5-6.6 g L-1. The fertilization rate was 90% of buoyant eggs, with a mean egg diameter of 0.857 +/- 0.044 rnm. Hatching occurred 15 hours after spawning (h.a.s.) at 26.3-28.2 degrees C. Larvae started feeding 65 h.a.s. and the postflexion stage was observed 27 days after spawning (d.a.s.). The critical period was observed 3-5 d.a.s., as in other lutjanid species. At 26 d.a.s., the growth rate was 0.243 mm d(-1) and the survival rate was 1.5%. The growth rate of the fingerlings (171 d.a.s.) was 0.2 g d(-1), with a mean body weight of 33.36 +/- 9.13 g. Naturally spawned larvae grew until 30 d.a.s., when massive mortality occurred