东方欧鳊(Abramis brama orientalis Berg)胚胎发育的初步观察

OBSERVATION ON THE EMBRYONIC DEVELOPMENT OF Abramis brama orientalis Berg

本文报导了东方欧(鱼扁)(Abramis broma Orientalis Berg)在新疆小水域条件下胚胎发育的初步观察结果,东方欧(鱼扁)是近数十年内才由苏联引进的鱼类,目前已成为新疆的主要经济鱼种,并已引种到北京、上海等十余省市,对其胚胎发育情况及所要求的条件,尽管苏联学者已做了不少工作,但在新的水域,特别是在人工孵化条件下的胚胎发育的情况,是渔业部门急待需要了解的问题.

The paper deals with the embryonis development of Abramis broma Orientalis Berg.The fertilized eggs of Abramis brama Orientalis Berg are spheroid in shape.They are 1.6～1.7mmin diameter,containing a large quantity of yolk.At the water temperature of 23.5～26.5℃,36 minutes after fertilization egg plusm begins toconcertruter towerds the animal pole of the egg and forms a raddish blastoderm.17 minutes after fertil-ization,it undergoes the first cleavag,1 hour and 39 minutes,it is the morula stage.2 hours and 12minutes after fertilization,blastodermal cells reaches the blastula stage.4 hours and 49 minutes after fertilization,the blastomers wrap downwards.This is the beginningof the gastrals stage.8 hours and 10 minutes after fertilization,the blastomers wrap downwards over 4/5 of yolk,withneural groove forming on th dorsul po(?)l of embryo.10 hours and 10 minutes later,body segment occur in the mid-part of embryo.11 hours and 45 minutes later fertilization,optic vesicles appear on both side of the fore brain.13hours and 23 minutes after fertization,the tail becomes moveable,19 hours and 45 minutes after fertil-ization,embryonis body begins to wriggle.24 hours and 13 minute after fertilization,heart is to pul-sate,8 hours and 30 minutes later,embryoes hatch out.The favourable water temperature for embryonic development of Abramis brama orentalis Berg is18～20℃,when tho temperature is higher than 20℃,embryonis development become shorter thanstanstill.