Silver pomfret,
Pampus argenteus (EUPHRASEN) is one of the commercially important fishes in Japan, and distributed from middle Japan to the South China Sea. It attains about 60cm in total length of the grown.
The seasonal occurrence of eggs in the sea, and the information about the gonad condi-tions of this fish caught by commercial gill nets suggest that the spawning season of silver pomfret extends from early July to late August in the middle part of the Seto Inland Sea and the peak is from late July through early August.
The authors carried out fertilization of this fish artificially and observed the egg develop-ment and hatched out larvae.
The egg is bouyant, colorless, spherical in shape, 1.20-1.35mm in diameter, and it con-tains a single oil globule of 0.43-0.45mm in diameter. The yolk is coarsely segmented around its animal pole. The hatching took place in about 24 hours after fertilization at 25.2-26.4°C of the water temperature (Fig. 1, a-h).
In the process of the development, many melanophores appeared on the embryonal body, yolk and oil globule. At the late embryonic development, orange-yellow pigment cells ap-peared on the embryonal body and posterior part of the yolk.
The larva just hatched out is 2.75-3.10mm in total length, and has the oil globule situ-ated at the posterior part of the yolk, and the anus opened somewhat posteriorly to the middle of the body. Melanophores distribute over the head, the trunk, anterior part of the yolk and the oil globule, Orange-yellow pigment cells also distribute over the posterior part of the eye, the dorsal surface of alimentary canal and the middle part of the tail where accompanying several melanophores. The myotome number is 13+22=35 (vertebral number of this fish is 34) (Fig. 1, 1).
Within five days after hatching out, the larva attained 4.10mm in total length, the yolk and the oil globule were entirely consumed and the head and the trunk became thicker. The melanophores gathered together around trunk part, and the orange-yellow pigment cells became faint (Fig. 1, 1).
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