Study on the early development and effects of ammonia on climbing perch (Anabas testudineus, Bloch) larvae

Abstract

The early life development and effects of ammonia on the climbing perch Anabas testudineus embryos and larvae were studied. The water bath system was used to maintain water temperature, dissolved oxygen (DO) and pH ranging from 29.0 - 29.8 °C, 7.4 - 7.8 mg/1, 7.64 - 7.73 during embryonic development and 28.8 - 30.9 °C, 6.8 - 7.5 mg/1 and 7.06 - 7.98 for larval development, respectively. Newly fertilized eggs were spherical with mean diameter of 0.93 ± 0.02 mm. First cleavage occurred 30 min after fertilization. The morula, blastula and gastrula stages occurred at 1:10 hour, 1:32 hour and 3:34 hours, respectively. The embryo stage began seven hours later with development of optic vesicle and pigment action followed by heartbeat and blood circulation. The embryos started to hatch 17 hours after fertilization and were completed within 2 hours. The newly hatched larvae were actively swimming one day after hatching and started exogenous feeding on day 2. A l l the yolk were absorbed 6 days after hatching and during this stage flexion occurred at the caudal fin. On day 8, the dorsal, anal and caudal fins had developed primordial finfold. Nine day old larvae have a compressed oblong body.