First studies of embryonic and larval development of Coilia nasus (Engraulidae) under controlled conditions

摘要

Herein, we describe the embryonic and larval development stages of Coilia nasus, an anadromous fish that is indigenous to the Yangtze River and the northwest region of the Pacific Ocean. The success of artificial breeding programmes and modern methods of reproduction allowed us to accurately describe the development stages of C. nasus. These stages were recorded using a binocular microscope and a digital camera-equipped microscope, and histological and scanning electron microscopy observations were also conducted. Development can be divided into four periods: embryonic, prelarval, larval and juvenile. The fertilized eggs were spherical, transparent, non-adhesives and buoyant, with an average diameter of 0.80±0.10?mm. Complete early embryonic development took place within 40–43?h post hatching, and the new hatchlings were 2.85±0.20?mm long. The mouth openings (0.25–0.35?mm) appeared at day 6 post hatching. Complete metamorphosis took place by day 60, at which time the larvae transformed into juveniles (65±5.8?mm) and attained skin coloration.