真蛸亲体培育、产卵及孵化试验

2005~2007年春、夏期间,在浙江南麂岛开展了真蛸亲体培育、产卵及孵化的试验研究。结果表明:亲蛸培育成活率为77.5%~95.5%,平均产卵率为68.0%~83.3%。不搭配雄体产卵率为65.0%,搭配一定比例的雄体后产卵率达92.5%,最高达100%。不同附卵器附卵效果以方形鲍鱼箱为最好,圆形鲍鱼皮桶次之,扇贝笼最差。在南麂海域暂养在网箱中的真蛸当水温上升到13.5℃以上时就开始有少量产卵,多数开始产卵在16.0℃左右,主要产卵期在4~6月。不同个体真蛸的产卵量变化很大,少者只有22 632粒,多者达170 684粒,平均102 665粒,平均每颗卵粒重量在1.670~2.207 mg之间,大小为长2.8~3.1 mm、宽0.915~0.950 mm。在水温13.5~28.0℃范围内,真蛸卵可以正常孵化,孵化率达60.0%~80.0%,超过28℃时孵化率明显下降。真蛸卵的孵化时间较长,至少需要20 d以上。孵化时间长短与水温关系密切,水温越高,孵化时间越短。孵化期间平均水温16.5℃,整个孵化时间长达47 d。当孵化期间平均水温为21.6℃时,从产卵到稚蛸出膜大致需要25 d左右。此外,还发现亲蛸护卵可以减少疾病,提高孵化率,本文也论述了有关其对疾病防治方面的探索。

Experiment on stock culturing, spawning and hatching of Octopus vulgaris

During spring and sumer of 2005-2007,the stock culturing,spawning and hatching of Octopus vulgaris have been experimented in sea area of Nanji Island.The results showed the survival rates of the stock were within 77.5%-95.5%,and the average spawning rates were 68.0%-83.3%.The spawning rate no arranged with the male was 65.0%,while that arraged with in male was 92.5%,even reached 100%.As for the efficiency of egg attached on the different devices,the square cage cultured abalone was the best,the cylindrical barrel was taken second place and the scallop net cage was the worse,when the water temperature rose to 13.5 ℃,the Octopus vulgaris temporarily reared in the net cages of the sea area of Nanji Island begun to spawn in a few matured adults,most of them begun to spawn about 16℃.The spawning period was from April to June.The fecundity vastly varied in different individuals ranged from 22 632 to 170 684 eggs per clutch.The average fecundity was 102 665 eggs per clutch.The weight of egg ranged from 1.670 to 2.207 mg,the length of them ranged from 2.8 and 3.1 mm,and the width was ranged from 0.915 to 0.950 mm.When the water temperature kept between 13.5 ℃ and 28 ℃,the egg of Octopus vulgaris could be hatched normally with the hatching rate ranged from 60.0% to 80.0%.As the temperature rose over 28 ℃,the hatching rate would be declined markedly.The time for hatching of Octopus vulgaris needed at least 20 days and more.The length of hatching time was closely related to the water temperature.The temperature the higher was the time the shorter.In the whole hatching period,the average water temperature was 16.5 ℃,and the time for hatching spanned as long as 47 days.As the average water temperature rose to 21.6 ℃ in the hatching period,the time span from spawning to hatching was about 25 days.It was noticed that the guarding egg behavior of the stock Octopus vulgaris could reduce the threatem of disease and promote the hatching rate.Furthermore,present paper also detailed the exploration on the prevention and control of diseases.