Observation on embryonic and larval development of Chalcalburnus chalcoides aralensis

This paper reported on artificial repreduction of Chalcalburnus chalcoides aralensis from Lake Ashiikul in Uzbeikstan and observed morphological characteristics of the embryonic and larval development in the fish.From mature population of three year-old wild fish and artificially bred fish, we selected well-grown individuals and conducted artificial obstetrics. The fertilized eggs were laid and hatched in the aquaculture tank. The fertilized rate was 97.6%, and the hatching rate was 83.3%. The mature eggs were sphaeroid in shape and (1.32±0.04) mm in diameter. The fertilized eggs are sticky and sinckly. Before the embryos hatching, it almost takes the main embryonic development stages including cleavage, blastula, gastrula, neurula, blastopore closed, appearance of eye bud, tail bud formation, musule effect, stage of embryoinc movement, stage of formation of heart and pre-stage of hatching. When water temperature was 22-24 ℃, the embryonic development took 56 h 45 min to develop into larva, and the total accumulative temperature was 1 232-1 344 h·℃. The mature fish of domesticated wild fish and artificially bred fish both kept the characteristics of hatching in fresh water and in blascky water as well. The larvae were (4.51±0.08) mm in total length on the first day after hatching, and the larval coluor was white, laying on the bottom of water. The larvae can feed yolk or single-cell algae on the fourth day after hatching. The yolk sac of the larvae disappeared on the sixth day after hatching, and the larvae fed rotifer or young chirocephalus. Since then, they have depended on feed exogenous for growth. On the tenth day after hatching, the larvae were cultivated in ponds at body length 7.60-(9.80) mm, and the larvae started to feed plankton. On the 15th day the length of larvae was 9.10-11.3 mm and began to intake artificial feed.