池养美洲西鲱的性腺发育进程

Gonadal development of Alosa sapidissima cultured in earthen pond

采用解剖学、组织学、形态测量等技术方法,研究了池塘培育美洲西鲱亲本初次性成熟性腺发育的进程。结果显示,池塘培育美洲西鲱雌雄鱼2龄开始初次性成熟,卵巢和精巢的发育进程呈现明显的阶段性,即等待期(12月5日前)、启动期(12月5日后)和快速期(雄鱼在3月7日后,雌鱼在4月20后)。雌雄亲本的体重与性腺重均呈良好的指数函数关系(y=a ebx,P<0.01)。雄性成熟期早于雌性成熟期约半个月,即Ⅴ期精巢出现在4月20日,而Ⅴ期卵巢则出现在5月6日,表明池塘培育美洲西鲱亲本催产的交配窗口期开始于5月6日。本文建议,长三角地区美洲西鲱亲本的池塘培育,应将雌雄亲本分开饲养,以减少互相干扰,同时适当降低雄鱼的培育水温;当亲本性腺发育进入快速期,应强化饲料营养,增加投喂频率;亲本的人工催产可选择5月初开始。

In order to determine the mating window time of Alosa sapidissima broodstock cultured in earthen pond imitation migration,the developmental processes of ovary and testis with the culturing time in A. sapidissima broodstock primary sexual maturation was studied. The results showed that the primary sexual maturity age of male and female A. sapidissima broodstock was 2-age, which was cultured in earthen pond imitation migration. The primary developmental processes of ovaries and testicles showed obvious stages: waiting period(before Dec 5), start-up period(after Dec 5), and fast period(after Mar 7 for males and after Apr 20 for females). In the gonadal primary developmental processes of A. sapidissima broodstock, the relationship between body weight and gland weight of male and female broodstock can be described by the exponential function(y=a e bx,P<0.01). The male testis matured about half a month ahead of female ovaries;the testis in the Ⅴ stage appeared at the Apr 20, and the ovarian in Ⅴ stage appeared at the May 6. According to the study, the mating window time of A. sapidissima broodstock cultured in earthen pond begins on May 6. Therefore, in the process of earthen pond imitation migratory culture of A. sapidissima broodstock, the male and female broodstock should be bred separately, and the breeding water temperature of the male broodstock should be lowered appropriately. When broodstock gonad enters the fast development period, the nutrient composition of the feed should be improved, feeding frequency should be increased appropriately;and artificial breeding should begin in early May.