施氏獭蛤室内规模化人工育苗技术研究

Studies on Large Scale Artificial Breeding of Lutraria sieboldii

为解决施氏獭蛤天然种苗匮乏和人工育苗技术尚不成熟的问题,促进其产业发展,于2013年开展了施氏獭蛤（Lutraria sieboldii Reeve）室内规模化人工育苗技术研究。采用池底铺沙,饵料以单胞藻为主,并辅以鸡蛋黄和淀粉,施氏獭蛤亲贝存活率89.7%,雄贝和雌贝性腺成熟率分别为89.1%和78.7%,亲贝产卵量126万粒/个,受精率达到93.4%。在水温25.5~26.5℃,盐度27.3~28.5条件下,施氏獭蛤受精后15 min和25 min分别释放第一极体和第二极体,受精后35 min达到2细胞期,约4 h 40 min形成原肠胚期,6 h 25 min形成担轮幼虫,受精后14 h进入面盘幼虫期。投喂不同的开口饵料,施氏獭蛤面盘幼虫生长速率不同。单独投喂湛江等边金藻、湛江等边金藻＋小球藻和单独投喂小球藻,5日龄幼虫壳长分别为130、118和105μm,说明单独投喂湛江等边金藻培育效果最好。湛江等鞭金藻＋小球藻、小球藻＋牟氏角毛藻、牟氏角毛藻＋湛江等鞭金藻、湛江等鞭金藻＋亚心形扁藻等不同饵料组合对施氏獭蛤幼虫和稚贝生长影响均差异显著（P〈0.05）,其中小球藻＋牟氏角毛藻组合培育幼虫效果最佳,而湛江等鞭金藻＋亚心形扁藻培育稚贝效果最好。不同附着基对施氏獭蛤幼虫的生长和存活产生显著影响（P〈0.05）。采用遮光网、聚乙烯网片、细砂、河口沉积泥和附着板5种附着基,考察幼虫生长和存活两个指标,结果表明,附着板效果最好。通过两批生产性育苗,亲贝的催产率达到90%,浮游幼虫平均存活率为84.3%,培育出壳长为2.5~3.0 mm的稚贝3 180万粒,平均稚贝育成率达到33.1%。

A large scale artificial breeding of Lutraria sieboldii was conducted in 2013. The results showed that by adopting methods of bottom culture in sand, feeding with microalgae, egg yolk and starch, the survival rate of parent shellfish reached 89.7 %. Gonadal maturation rates of male and female parent shellfish were 89.1 % and 78.7 % respectively,and the amount of spawned eggs of per parent shellfish was 1.26 million, of which the fertilization rate reached 93.4 %. Under the condition of water temperature of 25.5-26.5 and water salinity of 27.3-28.5,the first polar body（pb1）and the second polar body（pb2）were released respectively in15 min and 25 min after fertilization. About 35 min after eggs fertilization, the second cell stage was formed. As the cells divided, their number continued to increase. After about 4 h 40 min,6h 25 min and 14 h, gastrula,trochophore and D-shaped larvae was formed.. Shell lengths of Lutraria sieboldii veliger larvae increased with the time extension by fed with three different diets, including Isochrysis zhanjiangensis,Isochrysis zhanjiangensis plus Chlorella vulgaris,and Chlorella vulgaris,reaching 130μm,118μm and 105μm. Cultivation effect was best with Isochrysis zhanjiangensis as opening diet after 5 days cultivation. Lutraria sieboldiiv larvaes increased markedly by using four diets including Isochrysis zhanjiangensis plus Chlorella vulgaris, Chlorella vulgaris plus Chaetoceros muelleri,Chaetoceros muelleri plus Isochrysis zhanjiangensis,Isochrysis zhanjiangensis plus Platymonas subcordiformis. Compared with other 3 diets,Chlorella vulgaris plus Chaetoceros muelleri was best for larvae cultivation from early umbo larvae to creeping larvae. The same 4 diets had markedly effects on Lutraria sieboldii from attachment larvae to spat. Compared with other 3 diets,zhanjiangensis, Isochrysis zhanjiangensis plus Platymonas subcordiformis were best for larvae cultivation, with growth rate of shell lengths of 209.8 μm·d-1. Secondly,growth rate of shell length was 201μm·d-1 while fed Isochrysis zhanjiangensis plus Chlorella vulgaris. Growth and survival of Lutraria sieboldii larvae was affected by different attachment substances including shading network, polyethylene network film,sediment mud and attachment plate. Through observing growth and survival,attachment plate was the best attachment substance for Lutraria sieboldiiv larvae cultivation,with the growth rate of 252.4 μm·d-1 and the survival rate of 62.6%. Through the two batch of seedling production,induced spawning rate of parent shellfish reached 90%, the average survival rate of larvae was 84.3%.Total spats（shell length 2.5-3.0 mm）of 3180 were cultivated,and breeding rate of spat reached 33.1%.