长蛸(Octopus minor)初孵幼体培育与生长研究

BASIC GROWTH RELATIONS IN EXPERIMENTAL REARING OF NEWLY HATCHLINGS OF OCTOPUS MINOR(SASAKI,1920)

采用光滑河蓝蛤和菲律宾蛤仔两种双壳贝类培养长蛸幼体,分析其生长和存活情况。结果显示,长蛸初孵幼体无外卵黄,体表光滑,第一对腕(最长腕)约为胴长的2.9倍,腕吸盘两列,第1—4对腕平均吸盘数(n=3)分别为66±4.60、55±3.76、43±4.59和41±3.82;1—15d幼体投喂的是光滑河蓝蛤(壳长15.4—20.3mm),之后投喂菲律宾蛤仔(壳长33.2—39.3mm);幼体30d—70d总成活率由80.99%降至54.65%;整个培育过程中,幼体生长率与饵料效率呈极显著线性回归关系(P<0.01),y=1.452x-2.731(R2=0.865);1—80d胴长/全长比增幅高于腕长/全长,表明胴体增长快于腕的增长;各腕吸盘数变化不显著;幼体鲜重与培养天数呈指数函数关系,Wt=0.301e0.010t(R2=0.854,P<0.01);长蛸幼体最终生长率为122.05%,平均生长率为9.97%/10d。

Basic growth relations and pattern were studied in experimental rearing of newly hatchlings of Octopus minor during 80 days using Potamocorbula laevis and Ruditapes philippinarum as feeding diets.Results showed that the newly hatchlings of O.minor no longer had external yolk,with smooth mantle and the length of the first pair of arm was about 2.9 times of the mantle length,with two lines of suckers counting(66±4.60),(55±3.76),(43±4.59) and(41±3.82)(n=3) per arm from first pair to forth pair; 1—15d hatchlings were fed on shellfish P.laevis(shell length 15.4—20.3mm) during the night and then were fed on R.philippinarum(shell length 33.2—39.3mm); the total survival rate of hatchlings decreased from 80.99% at 30d to 54.65% at 70d; in the hatchling rearing process,growth rate showed a highly significant linear relation with feed efficiency(P<0.01),y = 1.452x-2.731(R2 = 0.865); ratio of MLd/TL increased more faster than the ratio of the AL/TL along with time showing the mantle grew faster than the arms; the amount of SC of each arm had no significant increase; the Wt of cultured hatchlings showed a highly significant power regression relation with culture days(P<0.01),Wt = 0.301e0.010t(R2 = 0.854).Finally,the growth rate of hatchlings was 122.05%,with an average growth rate 9.97% per 10 days.