12 JUNE 2015 • WORLD AQUACULTURE • WWW.WAS.ORG Post-Larvae and Genetics In recent years, hatcheries have significantly increased production to keep pace with demand, the result of a greater number of crops per year at the farm level. Today, there are about 18 operational shrimp hatcheries in northeast Brazil, with aggregate production that exceeds 1.5 billion PLs/mo. More than half of PL production in northeast Brazil originates from hatcheries that produce more than 150 million PLs/mo. At this scale, hatcheries are part of or have direct business involvement with grow-out farms. As a result, they are more capable of making investments in genetic improvement programs (Fig. 5). Because the Pacific whiteleg shrimp is not native to the Brazilian coast, there was speculation that inbreeding problems could occur if new stocks were not introduced. The last official introduction of L. vannamei in Brazil occurred in 2006 by a privately-owned hatchery to develop a new line of SPF (Specific Pathogen Free) shrimp. However, in a different approach, in 2004, another commercial hatchery started to develop local stocks to be IMNV-resistant and tolerant to stress factors (salinity, stocking density and hypoxia). The survival of these shrimp in commercial operations has been enhanced, even during challenging periods. This has driven new investments in similar breeding programs by other hatcheries, with a focus on tolerant shrimp to improve survival, other than disease-free stocks with a focus on growth. A. B. FIGURE 4. A typical shrimp nursery tank in northeast Brazil with protein skimmers in the back (A). Shrimp are stocked at 10-25 PLs/L, depending on targeted size at harvest. Use of automatic feeding, plastic covering, biofloc enriched-water (B, C) and lined ponds (D, E) represents a trend towards producing juvenile-size shrimp prior to starting grow-out. Photos: Celm Aquicultura S.A. and Alberto Nunes. C. D. E.
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