Embryonic and larval development of Thai Pangas (Pangasius sutchi Fowler, 1937).
The embryonic and larval development of Thai pangas was investigated during peak (May-July 1995) and late spawning (August-October 1995) periods. The fertilized eggs are adhesive and spherical with a yellowish or greenish-brown egg capsule. The yolk sac is yellowish-brown in color and 1.20-1.80 mm in diameter. Nine hours post-fertilization, the first cleavage stage, embryonic shield, head, tail region, neural grooves and somites were evident. The incubation period ranges from 24-36 h at a temperature of 20-30 degrees C. The newly hatched larvae are quite transparent and light yellowish in color with a body length of 2.98-3.10 mm. Eye pigments appear and the heart starts to work within 12-14 h of hatching. In 1-day-old pro-larvae, the mouth becomes well developed; barbules are elongated, prominent and look like tiny threads. The yolk sac is fairly well absorbed and the palatine teeth are fully developed during the 3 day pro-larval stage. At the end of 12 days of larval development, the stomach becomes functional and aerial respiration starts. After 2 weeks, the young fry is well-developed, and is of an adult appearance, that is, measuring up to 13.56 mm in length.
Islam
Asiful
A
Kazan State University, Kazan, 420008 Russia. asifuli@yahoo.com
D000818:Animals; D001837:Body Weights and Measures; D002397:Catfishes / Q000033:anatomy & histology* / Q000196:embryology* / Q000254:growth & development*; D004625:Embryo, Nonmammalian / Q000196:embryology; D007814:Larva / Q000033:anatomy & histology / Q000254:growth & development; D013785:Thailand; D013997:Time Factors; D015053:Zygote / Q000166:cytology