[Embryonic and Larval Development of the Asian Seabass Lates calcarifer (Pisces: Perciformes: Latidae) under Thermostatically Controlled Conditions].

Abstract

Material for this study was obtained from the hatchery with brood stock of Lates calcarifer that originated from a natural population living in inshore waters off Central Vietnam. Commercial interest in L. calcarifer as an object of mariculture and wildstock fishery has resulted in several publications on its early life history; nevertheless, comprehensive description of early development of L. calcarifer based on controlled incubation of embryos and larvae has remained absent. In the present paper embryonic and larval development to the stage of anlage of pelvic fins is described in detail and illustrated with original drawings of live material on the basis of thermostatically controlled incubation of embryos at 27°C and larvae at 26.8°C (26.5-28.0°C). The first cleavage furrow appeared at the age of 33.5 min. The duration of synchronous cleavage cycle was 16 min. About 80% of all embryos hatched at the age of 18 h. The length of newly hatched larva during the first hour after emergence from the egg shell was 1.63 ± 0.016 mm (1.50-1.75 mm). Chronology of development of the organs, early circulatory system, and pigmentation pattern is given. The dynamics of change in the trunk and caudal body segment number in larva from hatching to the moment of anlage of pelvic fins is shown. The total number of body segments reached the maximum value of 26-27 soon after hatching and then decreased to 20-21 segments. Newly received data are discussed in a comparative context of development of some other teleosts.