大黄鱼仔稚鱼脊柱、胸鳍及尾鳍骨骼系统的发育观察

研究采用二重染色法对3—28日龄人工培育的大黄鱼Larimichthys crocea(Richardson)仔稚鱼的部分骨骼系统的发育进行观察。结果显示,仔鱼的脊索从6日龄(平均全长MTL3.9mm)开始分节,8—10日龄髓弓、脉弓先后开始发育,14日龄(MTL7.5mm)脊椎骨、髓棘、脉棘均已形成,至28日龄(MTL19.5mm)已发生骨化;大黄鱼仔鱼孵化时,胸鳍的上匙骨、匙骨、后匙骨、支鳍骨原基已形成,27日龄(MTL19.0mm)稚鱼具5块支鳍骨,鳍条发育完整;尾鳍发育以8日龄仔鱼脊索后端腹部2块尾下骨的形成开始,至14日龄仔鱼尾鳍已初具雏形,尾杆骨、尾上骨和尾下骨均发育完全,21日龄稚鱼尾下骨排列成弧状,第三与第四块尾下骨之间的缝隙增大,把尾鳍鳍条分为上下两部分,鳍条分节明显,28日龄稚鱼尾鳍尾杆骨及鳍条发生钙化。

DEVELOPMENT OF THE VERTEBRAL COLUMN AND THE PECTORAL AND CAUDAL FINS IN LARVAE OF THE LARGE YELLOW CROAKER LARIMICHTHYS CROCEA (RICHARDSON)

The large yellow croaker Larimichthys crocea, one of the most commercially important marine fish in China, has been widely cultured in the South China Sea due to the success of artificial propagation in 1990s. Information about embryonic and morphological developments of larvae of this species is available, but little is known about its oste-ological development. In order to obtain the knowledge of the normal onset of skeletal structures throughout develop-ment, the developmental pattern of the vertebral column and the pectoral and caudal fins in larvae (3--28 days after hatching) of the cultured large yellow croacker Larimichthys crocea was studied. 50 specimens per day were collected and fixed in 5% formalin solution after measuring individual total length for later staining. Specimens were stained with alcian blue and alizarin red and observed for skeletal development. The results showed that larval notochord appeared segment at 6 d.a.h (MTL3.9mm). The vertebral column was formed at 14 d.a.h (MTL7.5mm) and then ossified by 28 d.a.h (MTL19.5mm). The supracleithrum, cleithrum, postcleithrum and the fin plate of the pectoral fin appeared right after hatching, and developed completely with five pieces of proximal pterygrophores and numbers of lepidotrichium at 27 d.a.h (MTL19.0mm). The development of the caudal fin began with the formation of the hypural at 8 d.a.h and well developed with three pieces of epural and five pieces of hypural that enclose the urostyle as well as lepidotrichia. The urostyle and lepidotrichia was fully ossified by 28 d.a.h.