Coastal Aquaculture and Mariculture (2+1)

Unit 6 - Culture of Crustaceans

6.1.5.b. Selection of shrimp fry (post larvae)

The most important criteria for selecting shrimp fry is the stage of development. The age of the fry influences size variation at harvest and the survival. Usually PL15 to PL20 are stocked. PL20 is the most ideal size to stock. If fry of size less than PL20 are stocked in the ponds it will result in least size variation but also low survival. If fry of more than PL20 are stocked in the ponds, it will improve survival but results in greater size variation.

What to look for in the fry

• Fry should be transparent and not cloudy or with white spots or covered with stains
• Rostrum and head should not be wrinkled
• Abdomen should have long black line along the body – indicates that the gut is full and therefore fry are healthy since they are feeding well
• Uropods should be well spread out
• Fry should be of uniform size
• Fry should swim against the currents.

The fry should be transported in polythene bags filled with water and oxygen in the ratio of 1:3.