Embryonic and larval development of black skirt tetra (Gymnocorymbus ternetzi, Boulenger, 1895) under laboratory conditions.

摘要

The embryonic and larval development of black skirt tetra, Gymnocorymbus ternetzi, are described under controlled laboratory conditions. In addition, major histomorphological changes and the allometric growth patterns during larval development have been described. The laboratory-reared broodstock, that is 1 year of age, were spawned. Hatching occurred 20-21 h after spawning at 24+or-0.5 degrees C. The cleavage was finished in 2 h and the early blastula stage occurred at 2:04 hours after spawning. The gastrulation started at 3:20 hours and 30% epiboly was observed at 3:34 hours after spawning. Eight-somite stage was observed at 08:33 hours. And embryonic developmental stage was completed at 21 h after spawning. The newly hatched larvae were 1442+or-14.3 micro m in mean total length (TL). The mouth opened at 3 days after hatching (DAH). The yolk sac had been totally absorbed and the larvae started to swim actively within 3-4 days. Notochord flexion began at 11 DAH. The metamorphosis was completed and the larvae transformed into juveniles at 32 DAH. In this paper, the full developmental sequence from egg to juvenile of G. ternetzi is described for the first time.