短蛸繁殖行为及胚胎发育过程

Reproductive behavior and process of embryonic development of Octopus ocellatus

采用光学显微镜观察的方法,对短蛸(Octopusocellatus)的胚胎发育过程进行观察。在人工养殖环境下,选用成体短蛸培养1个月后(五月份)即产卵。观察发现,雌蛸一直对其卵子进行看护,直到幼体孵化出膜,随后两周之内雌蛸相继死亡;受精卵卵裂方式为盘状卵裂。根据Naef的划分标准,短蛸胚胎发育过程划分为20期,期间胚胎经历2次翻转,受精卵的孵化水温为16～21℃时,第1次翻转发生在第15天,胚胎原基由动物极转向植物极;第2次翻转发生在第40天,胚胎由卵柄端转向卵柄相对端;从受精卵到幼体孵化出膜共经历41d;刚孵化出的幼体为浮游型,浮游期12d左右,之后营底栖生活。本文系统地描述了短蛸的繁殖行为和胚胎发育各个阶段的形态变化,旨在丰富短蛸繁殖生物学和胚胎发育生物学的基础理论研究,并为开展大规模开展短蛸人工育苗、养殖以及人工增殖放流提供科学依据。

Octopus ocellatus,the common name of which is short arm octopus,belongs to Mollusca,Cephalopoda,Octopodidae,Octopus,and widely spreads in the Bohai Sea,the Yellow Sea,and north of the East China Sea.It is tasty,highly nutritive,and enjoyed by many people,so,it is of great economic value.A large amount of O.ocellatus is captured from the nature,and exported to Korea and Japan.Because of over-capture,its resource has been declining rapidly,and is in urgent need of ecological restoration.At the same time,O.ocellatus has its advantages,eg,its life cycle is only one year,and it grows very fast.Therefore,it is a favorite species for artificial culture and proliferation discharge.Lots of research about embryonic development has been done on other cephalopod,such as O.vulgaris,Loligo pealei,Hapalochlaena lunulata,O.aegina and so on,but few study was done on O.vulgaris.This study focused on reproductive behavior and embryonic development of O.ocellatus.It was cultured in artificial environments for a month and then spawned.The female took care of her eggs from beginning till larva hatching.During this period,the female scarcely preyed,and died within fortnight after larva was hatched.The type of cleavage was discoidal cleavage.According to the standard of embryonic development,established by Naef,the process of embryonic development was categorized into 20 stages by characteristics.The process of embryonic development of O.ocellatus endured 2 reverses.The first reverse took place on the fifteenth day,in which embryonic anlage turned from animal pole to vegetal pole.At hatching temperature of 16—20℃ the second one was happened on the fortieth day,embryo turning from egg stalk to the opposite.In the end,larva was hatched after 41 d.The hatchling was planktonic,and they began benthic lifestyle about 12 d later.This research presented some useful data,which will be of great value on artificial breeding,culture and proliferation discharge.