Credit: Ahmed Zaki (Egypt)
The photos were taken in a tilapia hatchery in the Philippine. In this hatchery the broodstock of Nile tilapia, Oreochromis niloticus at the ratio of 3 females: 1 male. The swim-up tilapia fry are collected along the pond sides using a long-handled, narrow-mesh deep nets. The collected fry are transferred into special tanks to complete the sex reversal process using the male hormone (17α-Methyltestosterone). Because the newly hatched fry moves along the sides of the spawning ponds in schools and so the daily collections are done for more than ten times per day. This practice target to collect all of the fry because left-over fry when they grow in the spawning ponds will predate on newly hatched tilapia of new generations.
The spawning of Nile tilapia in the Philippines takes place all-year round. When the collected fry are on the decline, the water is lowered and the broodstock are transferred into recovery ponds and replaced by newer spawners in order to maintain a high level of spawning.