C0301 Step 5. Seed Selection

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1 Shrimp seed should be clean and undamaged
2 Test the seed for disease
3 Pack the seed in good condition and
transport quickly
4 Transport time from hatchery to shrimp ponds should be less than 6 hours
5 Acclimatize the seed in shrimp pond water before releasing
6 Calculate correct stocking rates

Select active and strong shrimp seed
• Always purchase shrimp seed from a well maintained hatchery or certifi ed hatchery.
• Prefer PL-12 stage or older (total body length should be more than 12 mm).
• Shrimp seed should be uniform in size and dark or light brown colour. Seed with red, blue or green colour must be rejected.
• Shrimp seed should pass a salinity stress test.
– Collect about 50 seeds in a glass with pond or brackish water and pour equal quantity of fresh water (drinking water). Wait for 3 hours. If more than 90% of the seed survives, then select the seed batch.
Select healthy shrimp seed
• Shrimp seed should have full gut and well developed
hepatopancreas.
– Collect 10-20 seed. Observe under a magnifying glass or
microscope.
– The gut should not be empty.
– The hepatopancreas should not be small and light in colour.
• Shrimp seed should be clean and without any damaged or missing legs.
– The same 10-20 seed should be also checked for any dirt on body surface and broken, blackish or missing legs. If these signs are found then reject the batch.
Test the seed for disease
• Shrimp seed may have pathogens like White Spot
Syndrome Virus (WSSV) and Monodon Baculo Virus (MBV).
Viral related disease can cause mass mortality of shrimp in
shrimp ponds.
• Collect and pack about 100 seed in a seed bag and send to a fish health laboratory for disease testing.
• The result should be negative for WSSV by PCR test. Similarly it should be negative for TSV if it is relevant in the farming area.
• If you do not have a laboratory facility nearby, use dot blot test kit (eg. ShrimpleTM test kit) to test for WSSV. If double bands appear on the kit then reject the seed batch. If only single band appears on the kit then the batch can be selected.
• Also test for MBV by simple microscopy (staining ethod). If MBV infection is medium or very high, then do not select the seed batch
Pack the seed in good condition and transport quickly
• Do not mix the seed batches from different seed tanks of a hatchery or from different hatcheries.
• The salinity of seed tank water and shrimp pond water should be the same and should not differ by more than 5 ppt.
– Prior to packing the seed adjust the salinity of the seed tank water to the salinity of shrimp pond water. Start adjusting the salinity at PL-10 stage and complete the
process of adjusting at least one day prior to seed packing.
• Bags should have enough oxygen (water : oxygen = 1:3)
• Each bag should have about 1000 PL (1000-2000 PL/ltr water)
• Transport time from hatchery to shrimp ponds should be less than 6 hours
• If transportation time is longer, slightly reduce the temperature using chilled water and transport in thermocool boxes.
• Transport during cool hours of the day (6 PM – 7 AM)
• Transport in enclosed vehicle.
Acclimatize and release the seeds in to pond after 06.00 pm or before 8.00 am
• Make sure the plankton bloom is strong and stable (green colour water). Avoid stocking if shrimp pond has transparent water or dark green water.
• Stock the seed in deeper part of the shrimp pond, not in shallow water.
• Acclimatize the seed in shrimp pond water before releasing
– Keep the seed bags floating in water for 20-30 min.
– Slowly mix the shrimp pond water in seed bag during next 30 min, and then release the seeds to shrimp pond.
Avoid seed from poorly managed commercial nurseries

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