饵料与底质对三角帆蚌稚蚌早期生长的影响

为寻找三角帆蚌Hyriopsis cumingii合适的饵料和底质,提高三角帆蚌稚蚌成活率,在水温(24±1)℃下分两个阶段测试了不同饵料和底质对三角帆蚌稚蚌的生长影响,第一阶段测试了两种底质(黄泥、黄泥加钙粉)和两种饵料(Nanno 3600藻、Shellfish diet 1800藻)对1~30 d稚蚌成活和生长的影响,第二阶段测试了5种饵料(Nanno 3600藻、Shellfish diet 1800藻、普通小球藻、四尾栅藻、卵囊藻)对31~60 d稚蚌成活及生长的影响。结果表明:第一阶段中,投喂Nanno 3600藻且以黄泥为底质的组(A3)与投喂两种混合藻且以黄泥为底质的组(A1)稚蚌成活率无显著性差异(P0.05),但二者均显著高于投喂两种混合藻且以黄泥+钙粉为底质的组(A2)(P0.05),A1、A2、A3组均与投喂Shellfish diet 1800藻且以黄泥为底质的组(A4)和池塘水养殖且不投喂的组(A5)呈极显著性差异(P0.01),A2组稚蚌生长最快,壳长显著高于A1、A3组(P0.05),A1、A2、A3组极显著高于A4、A5组(P0.01);第二阶段中,池塘水养殖组(B5)成活率显著高于卵囊藻组(B1)、小球藻组(B2)、Nanno 3600藻组(B4)(P0.05),极显著高于四尾栅藻组(B3)(P0.01),B5组与B4组稚蚌壳长无显著性差异(P0.05),均显著高于B1、B2组(P0.05),极显著高于B3组(P0.01)。研究表明:稚蚌在1~30 d时添加藻类可提高稚蚌存活率,且以微拟球藻效果最好,底质中添加钙粉有利于稚蚌生长;稚蚌在31~60 d阶段,投喂微拟球藻更有利于稚蚌的生长。

Effects of diet and substrate on early growth of juvenile freshwater mussel Hyriopsis cumingii

Two feeding trails were conducted to study effects of different diets and sediments on growth of juvenile freshwater mussel Hyriopsis cumingii at water temperature of (24±1)℃ in order to find suitable diets and sediment for survival of freshwater mussel juveniles. In the first trail, effects of two different substrates (fine sediment and fine sediment with calcium powder) and two diets (Nanno 3600 and Shellfish diet 1800) on survival and growth of 1-30 d old freshwater mussel juveniles (freshly metamorphosed) were tested, and in the second trail, influences of five diets (Nanno 3600, Shellfish diet 1800, Chlorella vulgaris, Scenedesmus quadricauda and Oocystis sp. ) on survival and growth of 31-60 d old juveniles were studied. The one-way analysis of variance revealed that there was no significant difference in survival between the juveniles in group A3 fed Nanno 3600 and fine sediment (P>0. 05) and in group A1 fed mixed algae and fine sediment, significant difference (P<0. 05) that in the juveniles fed mixed algae in group A2 and fine sediment with calcium, and very significant difference (P<0. 01) with group A5 which was cultured in pond water collected from the Freshwater Fisheries Research Center. The best growth was observed in the juveniles in group A2, with far higher shell length than those in groups A1 and A3 (P<0. 05) and very far higher than those in groups A4 and A5 (P<0. 01). In the second stage, group B5 presented significantly higher survival rate compared to groups B1, B2 and B4 (Shellfish diet 1800) (P<0. 05), and very significantly higher survival rate compared to group B3 (P<0. 01). There was no significant difference in shell length between group B5 and groups B4 (P>0. 05), significance difference in groups B1 and B2 (P<0. 05), and very significant difference with group B3 (P<0. 01). It can be concluded that the survival will be improved in 1-30 d old juveniles fed Nannochloropsis oculata in Nanno 3600, and that adding calcium in sediment is conducive to the growth of the juveniles. Nannochloropsis oculata is more conducive to growth of the 31-60 d old juvenile freshwater mussel.