中国蛤蜊人工育苗技术的初步研究

The artificial breeding technique for surf clam Mactra chinensis

于2008年4—10月在庄河海洋贝类养殖场对中国蛤蜊Mactra chinensis的人工育苗技术进行了研究,至10月份成功培育出壳长为(9.12±1.13)mm的稚贝共计64 030粒。结果表明:在海区采集的中国蛤蜊亲贝的雌雄比例为1.02∶1,产卵量为74.1万粒/个;在温度为23～24℃、盐度为24～26、pH为8.02的条件下,受精卵经过23.5 h发育为D形幼虫;中国蛤蜊的卵径、D形幼虫、足面盘幼虫的大小分别为(54.4±1.64)、(70.91±3.75)、(216.5±12.48)μm,变态规格、出现单水管、双水管的稚贝大小分别为(240.42±6.56)、(248.22±14.14)、(1 175±72.31)μm。浮游期间(0～10日龄),水温为22.7～23.4℃,幼虫生长速度为(11.16±0.45)μm/d,存活率为(92.80±2.34)%;变态期间(10～15日龄),水温为22.4～24.2℃,幼虫生长速度为(10.91±0.54)μm/d,变态率为(73.16±8.32)%,变态过程持续5～6 d。稚贝期间(15～40日龄),水温为24.2～27.0℃,双水管稚贝的生长速度明显快于单水管稚贝,但存活率明显下降。单水管稚贝的生长速度为(73.98±9.05)μm/d,存活率为(73.6±6.58)%;双水管稚贝的生长速度为(87.95±8.34)μm/d,由于水温过高(>30.0℃),存活率仅为(13.78±3.65)%。幼贝期间(40～100日龄),其生长速度为(111.24±13.08)μm/d,存活率为(62.75±5.35)%。

Artificial breeding technique of surf clam Mactra chinensis was carried out and 64 030 juveniles with shell length of （9.12± 1.13 ）mm were produced at a hatchery of bivalves at Zhuanghe county from April to October in 2008. The results showed that the sex ratio （female/male） was 1.02：1 and fecundity was 741 thousand/ind in the wild broodstocks. The embryonic development lasted 23.5 hours to D larva stage at water temperature of 23 - 24 ℃, a salinity of 24 - 26 and pH 8.02. The egg, D - larvae, settling larvae, metamorphosis, and single siphon, and double siphon juveniles were （ 54.4 ± 1.64 ）, （ 70.91 ± 3.75 ）, （ 216.5 ± 12.48 ）, （ 240.42 ± 6.56 ）, （ 248.22 ± 14.14）, and （1175 ± 72.31 ）μm in size, respectively. The larvae had growth rate of （11.16 ± 0.45 ） μm/d with survival rate of nearly 100% during pelagic stage from day 0 to day 10 at 22.7 -23.4 ℃. The larval metamorphosis was prolong 5 - 6 days, and had growth rate of （ 10.91 ± 0.54 ） μm/d with metamorphic rate （73.16±8.32） % at 22.4 -24.2 ℃. There was significantly better growth in the double siphon juveniles than that in the single siphon juveniles, for the survival rate, however, decrease in the juvenile rearing stage from day 10 to day 45 at 24.2 - 27.0 ℃. The single siphon, and double siphon juveniles had good growth at average of （73.98 ±9.05）μm/d, （87.95 ± 8.34）μm/d, respectively. Meanwhile the single siphon juveniles had survival rate of （73.6 ± 6.58 ） %, and the double siphon juveniles only （ 13.78 ± 3.65 ） % due to higher temperature above 30 ℃. The juveniles showed growth rate of （ 111.24±13. 08 ） μm/d, with survival rate of （62.75 ± 5.35） % during grow out stage from day 40 to day 100.