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After eyestalk ablation females are checked for ovarian maturation daily and removed to the spawning facilities when ripe. A single female may spawn one to six times. Percent fertilization, hatch, or nauplii-protozoea transformation are monitored to assess broodstock performance. When performance in a maturation tank drops below an acceptable value, the broodstock are replaced with new animals. Gravid mated females are removed from the maturation tanks and placed in individual circular tanks. Gentle aeration is provided. Typically, the females spawn during the first night. In the morning, spawning tanks are checked for fertilized eggs. Fertilized eggs may be recovered using a 120 µm screen and transferred to the hatching tanks, or left in place to hatch and collected after hatching. Spawned females are returned to the maturation tanks. Egg collectors can be used to remove eggs from spawns in the maturation tanks. Fertilized eggs from the spawning tanks are placed in individual circular or rectangular hatching tanks. Gentle aeration is provided. In normal conditions fertilized eggs hatched within 12-15 hours. Nauplii are photopositive; they can be concentrated with light and removed by siphoning. After hatching the newly hatched nauplii are stocked at a density of 100-150 nauplii per liter in the larval rearing tanks. Here they grow from nauplius through protozoea to post-larvae. Before post-larvae are stocked in the growout ponds, they are first reared in nursery ponds or tanks. P21-P25 are suitable for harvesting from nursery tanks because this size can be stocked directly to the pond and easily be transferred. The larvae can be harvested by first reducing the water level and then can be collected from the bag net or box positioned at the tip of the drained pipe. Harvested larvae are counted and then transported to the growout ponds.
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