Parentage testing for hatchery-produced abalone <Emphasis Type="Italic">Haliotis discus hannai</Emphasis> based on microsatellite markers: preliminary evaluation of early growth of selected strains in mixed family farming

This study dealt with the detection of parentage in a mixed family tank of abalone Haliotis discus hannai using microsatellite DNA markers. As a preliminary investigation, the early growth rate between selected and non-selected abalone families, which were reared together in the mixed family tank from settlement stage to juvenile stage (7 months of age), was also compared. The selected families were derived from seven parents (three females and four males) selected for larger size in shell length at about 1-year-old, and the non-selected families originated from five wild captives (three females and two males). Parentage analysis based on eight microsatellite markers unambiguously allocated the 170 juveniles sampled from the single tank to the 17 parental pairs. The family size was highly heterogeneous among families, as two males in the selected families and one male in the non-selected families dominated the contribution to the offspring pool (>80%). The mean shell length of the selected families was approximately 23% larger than that of the non-selected families (Student’s t-test, P<0.001). This study demonstrated that the use of microsatellite markers is effective for parentage determination in the mixed family farming, commonly used in abalone hatcheries, and selective operations for larger size could improve the growth of the next generation.     

Triploidy induction in Australian greenlip abalone Haliotis laevigata (Donovan) with cytochalasin B

Triploid induction in Australian greenlip abalone, Haliotis laevigata (Donovan), was conducted by blocking the formation of the second polar body using cytochalasin B (CB). Twenty minutes after fertilization, the zygotes of greenlip abalone were treated with four CB concentrations (0, 0.25, 0.5 and 0.75 mg L⁻¹) for 10, 15 and 20 min. The ploidy of resultant larvae was determined using flow cytometry at 72-h post fertilization. Our study showed that fertilization, hatching, survival and induced triploidy of abalone larvae were significantly affected by the CB concentration and treatment duration. The effective range of CB concentration for triploid induction on greenlip abalone was 0.5–0.75 mg L⁻¹ with an induction duration of 10–15 min. The results indicate that the most effective treatment combination for triploid induction in greenlip abalone is 0.5 mg CB L⁻¹ for 15 min starting at 20-min post fertilization.     

Time to recover the upright posture in juvenile abalones (Haliotis discus discus Reeve, H. gigantea Gmelin and H. madaka Habe)

The adoption of an upright posture in abalones is essential to enable them to use their foot, and hence to be able to move and seek shelter, as well as to avoid exposure of soft parts and possible predation. In mass restocking programs for abalone, juveniles are released by divers near the seabed, but without control over their posture when they reach the bottom. Thus, the time to recover the upright posture is an important consideration in abalone restocking programs as the quicker they assume this posture the higher the likelihood of survival. This study reports significant differences in the speed of recovering the upright posture between juveniles of the abalones Haliotis discus discus, H. gigantea and H. madaka and between tests conducted under stagnant and flowing water conditions. Longer times were required for recovery in all species in stagnant than flowing water. On average, juveniles of H. discus discus (17.16 and 10.43 s) and H. gigantea (22.54 and 11.89 s) recovered faster than those of H. madaka (161.13 and 49.02 s) under stagnant and flowing water conditions respectively. These results suggest that different species require different levels of care and that water flow or current at the time of release may affect post‐release survival.     

总氨、亚硝酸氮及养鲍污水对皱纹盘鲍生长的影响

单因子总氨氮(TNH3-N)、亚硝酸氮(N02^--N)试验表明，当养鲍用水中非离子氨氮(NH3-N)为0．035mg／L以下或N02^--N为0．8mg／L以下时，对皱纹盘鲍Haliotis discus hannai Ino幼鲍的生长不产生明显影响；NH3-N对幼鲍生长产生影响的EC5(引起幼鲍生长速度减慢5％的浓度)为0．103mg／L，不产生影响的最大浓度为0．045mg／L。双因素试验结果表明，水中TNH3-N、N02^--N对幼鲍生长的影响没有交互作用，只是简单的相加作用。经回归表明，养鲍自污染水中，NH3-N是影响幼鲍生长的主要因子，它对幼鲍生长产生影响的EC5为0．022mg／L，不产生影响的最大浓度为0．0lmg／L，均比单因子试验结果显著降低。     

Growth and feeding in juvenile triploid and diploid blacklip abalone, Haliotis rubra (Leach, 1814), at two temperatures

Growth and feeding of juvenile triploid and diploid blacklip abalone Haliotis rubra (Leach, 1814) were investigated at two temperatures of 17 and 21 °C over a 50‐day period. There were no differences in growth between triploid and diploid abalone as measured by shell length and body weight. Both triploid and diploid abalone increased in length but not in weight at 21 °C. Condition indices were similar for triploid abalone maintained at both temperatures; however, those for diploid abalone were significantly higher at 17 °C than at 21 °C. Food intake was significantly greater yet feed conversion efficiency was significantly lower in triploid than in diploid abalone. Both the feeding variables were independent of temperature. On average, diploid abalone were able to convert 1 g of dry food ingested to 0.58 g of body weight, but triploid abalone only 0.44 g.     

皱纹盘鲍苗种南方越冬的试验

将在大连地区繁育的平均壳长2.2cm的皱纹盘鲍苗种运至福建省莆田市海域进行海上越冬,使用底面积为350mm×550mm、层间距150mm的7层专用养鲍笼,养殖密度25～80枚/层,饵料为盐渍海带、鲜紫菜、鲜海带苗。经5个月饲育,鲍苗平均壳长增长1.94cm,成活率达94.5%,效果明显优于北方沿海的室内越冬及海上越冬。     

一种生态化鲍育苗和养成模式的构建

该研究目的是建立一套鲍育苗和养殖的生态化模式,包括鲍苗种生态培育模式、鲍陆基生态养成模式和海上鲍藻套养生态养成模式,以克服目前鲍养殖业存在的病害频发、成活率低下等问题,提高鲍养殖的经济效益,降低养殖风险。鲍苗种生态培育模式通过＂光照-微藻-微生态制剂-滤食性动物-鲍苗＂构建复合生物体系;鲍陆基生态养成模式通过池内建立＂复合生物区系＂,并在池外设立生态塘和生态渠进行养殖废水处理的方式构建;海上生态养成模式通过＂鲍藻套养＂构建。共培育鲍苗5批次,培育周期210～240d,共产出鲍苗17.764×104个,平均壳长1.5cm以上,育成率0.78%～1.23%。陆基生态化模式养成商品鲍43.774×104个,平均壳长6.53cm,平均体质量34.6g,成活率87.5%,周期18～20个月。海上鲍生态养成150口网箱,养成商品鲍3×108个,平均壳长6.50cm以上,成活率85%以上,养成时间18～20个月。     

港湾海域新型网箱养鲍新技术探讨

根据鲍的生活习性,总结国内外养鲍设施特点,自行研发新型竖排式网箱。通过在港湾海域进行新型竖排式网箱的养鲍试验,对养鲍过程中网箱内饵料分布、附着生物情况进行研究,并与传统挂笼养殖模式对比分析。结果表明:新型网箱养殖过程中采用平潮点倾倒法投喂龙须菜或海带,鲍匍匐基内的饵料占比分别为:龙须菜约30.4%,海带约36.7%,均高于其它投喂方式。经过9个月的养殖,网目为1 cm的竖排网箱中的鲍最终体重为(29.1±6.17)g,存活率为60.5%,传统挂笼中鲍体重为(22.8±7.93)g,存活率为33.5%,新型网箱养殖效果显著优于传统挂笼(P0.05);不同网衣规格的网箱表面附着生物附着量无显著性差异(P0.05),但均显著大于传统挂笼组(P0.05),进入夏季后,网箱中附着生物的生物量和丰富度都有显著增加。与传统挂笼相比,新型竖排式网箱具有水体交换好、操作简单、节省劳力、存活率高等优点。     

驯化摄食对黑鲍饵料选择性的影响研究

研究了黑鲍(Haliotis discus hannai♀×H·discusdiscus♂)对裂片石莼(Ulva faxciata)、龙须菜(Gracilaria lemaneiformis)、海带(Laminaria japonica)、细基江蓠繁枝变种(G·tenuistipitata)、舌状蜈蚣藻(Grateloupia livi-da)和人工配合饲料6种饵料的选择性,继而通过实验研究了强制摄食驯化对黑鲍饵料选择性的影响。实验发现,在无饵料强制驯化的状态下,黑鲍对几种实验海藻的选择性依次为海带>石莼>江蓠>龙须菜>蜈蚣藻;在用单一饵料强制驯化7d后,黑鲍对几种实验海藻的选择性依次为海带>江蓠>石莼>龙须菜>蜈蚣藻。而黑鲍对人工配合饲料的摄食存在随机性,没有一定的规律。研究表明,海带是黑鲍最喜食的饵料,前期摄食驯化对其饵料选择性没有显著的影响。