铠平鲉的繁殖生物学特征及胚胎发育

Reproductive biology and embryonic development of Sebastes hubbsi

为了解铠平鲉繁殖生物学特征及胚胎发育规律,完善铠平鲉繁殖生物学研究内容,为其种质资源保护和资源可持续利用提供基础资料,实验利用春季于青岛胶州湾海域采集的铠平鲉生殖群体样本,开展了其繁殖生物学研究,并使用显微数码摄像系统,观察了铠平鲉体内胚胎的发育过程,定性和定量描述了各发育阶段胚胎的形态特征。结果显示,实验采集样本的体长范围为62~137 mm,体质量范围为9.4~126.8 g,雌雄性比为1.85∶1,最小性成熟年龄为2龄,生殖群体主要由2~4龄个体组成,初次性成熟体长为70.6 mm。绝对怀卵量F为656~9235粒,平均3176粒,体长相对怀卵量FL为12~67粒/mm,体质量相对怀卵量FW为72~140粒/g。雌鱼体内受精卵呈正圆球形,平均卵径为(1.50±0.03)mm,淡黄色,自心跳期开始,受精卵逐渐由正圆球形变为梨形。受精卵在海水中为沉性,具多个油球,在胚胎发育早期存在油球聚合现象,一般至原肠胚末期时仅剩1个大油球。雌鱼体内初孵仔鱼全长(5.57±0.06)mm。研究表明,虽然卵胎生铠平鲉的胚胎发育规律与大多数海水硬骨鱼类基本相似,但胚胎发育中油球数量、色素分布和受精卵外部形态变化等仍具有其特异性。

The study was designed to know the characteristics of reproductive biology and embryonic development regularity of Sebastes hubbsi,to accumulate basic data for further study on protection and sustainable utilization of this fish resources. The reproductive biology and embryonic development of S. hubbsi were studied based on 283 samples of breeding stocks caught in spring in Jiaozhou Bay,Qingdao,from April to May 2015. After obtaining fertilized eggs from female fish,we observed the embryonic development using the microscope and examined the morphological characteristics of each development stage. The collected samples had a body length ranging from 62 to 137 mm,a body weight ranging from 9.4 to 126.8 g,and an age range of 2 to 4 years. The female-male sex ratio was 1.85∶1 and the first sexual maturity age was 2 years. The body length of the species at the first sexual maturity age was 70.6 mm. The individual absolute fecundity F ranged from 656 to 9235（mean 3176） eggs. The individual length-specific fecundity to body length FL ranged from 12 to 67（mean 29） eggs per mm and the individual weight-specific fecundity FW ranged from 72 to 140（mean 108） eggs per gram. The egg of S. hubbsi was globular with a light yellow color and had multiple oil globules of varied size. The sterilized eggs would sink in the water with an average diameter of（1.50±0.03） mm. With the embryonic development,all oil globules of the egg gradually merged into a single one until at about the late gastrula stage,and the eggs gradually changed to pear-shaped from the heart beat stage. The newly hatched larvae were still in the ovarian cavity and had a total length of（5.57±0.06） mm. The embryonic development of ovoviviparous teleost Sebastes hubbsi seems to be similar to most of the marine teleost fishes,but there were still some characteristics different from others such as in pigmentation,oil globule variation,morphological change of eggs,etc.