Centropomus parallelus

Abstract: The fat snook, Centropomus parallelus, is a commercially valuable marine fish species with potential for aquaculture. This paper describes the development of technology for mass production of fat snook juveniles at the Experimental Fish Hatchery of the Universidade Federal de Santa Catarina, focusing on research about reproduction, larviculture, and juvenile rearing. Induced spawning of wild fat snook was first achieved in 1991 with a single injection of human chorionic gonadotropin (hCG). There was a substantial increase in egg quality when broodstock was conditioned in maturation rooms and induced to spawn. Different dosages of luteinizing hormone-releasing hormone analogue (LHRHa) with saline injection and colesterol implant were also tested. As fat snook exhibits group-synchronous oocyte development, females could be induced to spawn (with 35–50 μg kg−1 of LHRHa) once a month, resulting in up to four consecutive spawnings. Results of larval culture were highly variable at the beginning; survival rates were frequently around 1% until the juvenile stage. Several experiments were conducted to evaluate the effect of environmental factors and feeding quality on survival and growth. With the improvement of the spawning induction technique and better larviculture practices, survival rates increased to 10–30%. Studies on the particular requirements of juveniles in terms of stocking density, feeding, nutrition, and environmental factors were also performed in order to improve growth rates and feed utilization. The present study demonstrates the feasibility of mass production of fat snook juveniles. However, further research is needed to develop cost-effective grow-out technology.

Abstract: Western Atlantic centropomids, especially snook (Centropomus undecimalis), have potential for culture as food fish in fresh- or saltwater ponds, pens, or raceways. In this study, snook and tarpon snook (C. pectinatus) were reared to market size. Salt water was required for rearing early larvae, but juveniles grew fastest in fresh water at 27-28°C. A suitable feeding program included: rotifers (Brachionus plicatilis) and Artemia sp. nauplii, followed by dry starter and grower feeds. Feed conversion values (dry weight of feed eaten/wet weight gained by fish) for experimental dry feeds fed to snook weighing 16-725 g were in the range 0.7-1.1. Feed conversion was directly related to carbohydrate content and inversely related to protein content. Shook will begin to eat dry feed within 35 d after hatching and, at temperatures of 26-30°C, can be reared to a mean weight of 450 g in 1 year or less with a feed cost of less than $0.30/ fish. The slower-growing and thinner tarpon snook is a less likely candi...