Nursery Systems

Different types of nursery systems are in use around the world to raise bigger shrimp postlarvae or juveniles. From small nursery tanks around 50 square meters and 1 meter deep [50 MT of water] to 1-2 hectares earthen ponds are being using as nursery units. Some differences in performance and objectives among them, while the samallest are commonly used to grow postlarvae [PL] up to the equivalent to 20 PL per gram [PLG], the biggest are used to raise juveniles normally reaching 1-2 grams in size. Farmer must carefully select the appropriate size and format [round, rectangular, etc] together with the whole system design that include components like filters and others in order to guarantee the correct management and water quality for the shrimp. Different approaches are observed regarding the protocols for nursery management, these normally include flow through water exchange, batch water exchange, zero water exchange with bioflocs and beneficial bacteria to reduce sludge. Special attention must be given to the presence of some Vibrio species that could be deleterious to the cultures in progress. TCBS and ChromAgar Vibrio are the most common culture media used to monitor these bacteria.

Some authors stated that keeping the postlarvae/juveniles in constant water temperatures of 32 degrees Celsius, WSSV could be eliminated or replication could be inhibited, so in this case, at the same time that cover design and material must be considered to achieve this goal, aeration design and equipment must be carefully defined to avoid problems due to low oxygen levels correlated to higher temperatures.

2000 m3 raceway to raise juveniles of P. vannamei

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