高寒地区蓝鳃太阳鱼养殖技术研究

本探讨了蓝鳃太阳鱼（Lepomis macrochirus)在高寒地区的生长成活状况。实验结果表明，在东北地区蓝鳃太阳鱼夏季养殖成活率可以达到85%（单养）和65%（混养），6-8月生长速度较好，混养比单养生长速度快，冰下可以安全越冬。     

Effect of bovine colostrum intake on growth,reproductive parameters and survival in red kids

The aim of this study is to evaluate the efficacy of frozen Azawak colostrum supplementation on body weight (BW), average daily gain (ADG), reproductive parameters (mean age at first parturition, fertility, fecundity, prolificacy) and mortality rate among red kids. The study was conducted at the goat farm secondary centre of Maradi in Niger from September 2010 to September 2011. The control animals (n = 20) were left with their mother, while the treatment animals (n = 20) received in addition 50 ml/animal/day of bovine colostrum at birth and 15 ml/animal/day from d2 to d15. Weight was measured weekly from birth to d365. Mortalities were also recorded over the same period. For reproductive parameters, observations began at weaning (d197). Growth rate was higher (p < 0.001) in supplemented animal, and the treatment effects on ADG were observed up to 150 day after the end of supplementation. A similar long‐lasting trend was also observed in relation to the mortality rate (25% for ColG vs. 55% for ConG; p = 0.05). The age at first kidding tended to be lower in the treated group (13.8 ± 0.7 vs. 14.1 ± 0.8 month; p < 0.1). In conclusion, mild bovine colostrum supplementation induces a long‐lasting positive impact on growth rate and to a lower extent on reproduction parameters and survival rate.     

Preliminary observations on the tank and pond culture of the glass eels of the Australian shortfin eel, Anguilla australis Richardson

There is expanding interest in the culture of the Australian shortfin eel Anguilla australis Richardson; however, there is a lack of fundamental biology and husbandry information necessary to further develop an industry within Australia. The present study was undertaken to gain a preliminary understanding of basic husbandry requirements for rearing of juvenile A. australis (glass eels and elvers) in tanks and earthen ponds. Newly caught glass eels were successfully acclimated to culture conditions. During tank culture trials, specific growth rates (SGR) and survival rates ranged from ?2.1 to 2.8% day^?1 and 52% to 100% respectively. Glass eels weaned onto a commercial eel diet exhibited a significantly greater SGR and survival rate than those weaned onto a commercial trout diet. Glass eels weaned onto an eel diet over a 15‐day period grew slightly faster than eels weaned over a 5‐day period, but survival rates were not significantly different for each treatment. SGRs (up to 2.8% day^?1) were significantly higher for glass eels fed at 9 and 12% day^?1 than at 6% day^?1. Stocking densities between 2.5 kg m^?3 and 30 kg m^?3 did not influence either SGR or survival rates. SGRs were significantly higher for glass eels cultured at 25 °C than at lower temperatures. During pond culture trials, SGRs and survival rates ranged from 1.36 to 1.65% day^?1 and 39% to 77% respectively. The SGR and survival rates of juvenile eels stocked into ponds receiving supplementary feeding with a commercial eel diet were not significantly different to those of eels stocked into ponds that did not receive supplementary feeding.     

Hatchery production of diploid and triploid clams, Tapes dorsatus (Lamarck 1818): a potential new species for aquaculture

To assess the potential for hatchery production of the venerid clam, Tapes dorsatus, diploid and triploid clams were produced and ongrown until the spat reached 5–8 mm in size. Triploidy percentages at metamorphosis that ranged from 56 to 85% were induced using a 15-min exposure to 1 mg/l cytochalasin B. No differences were observed in the growth rate of sibling diploid and triploid T. dorsatus larvae. Survival of diploid clams to pediveliger stage was however higher. Post-metamorphic growth and survival of diploid and triploid clams remained the same until the clams were removed from the hatchery to outdoor nurseries. Throughout the larval and early spat phases of production, T. dorsatus growth was similar to that reported for the Manila clam, Tapes philippinarum. Based upon its ease of culture, rapid growth and marketability, T. dorsatus are thought to have considerable aquaculture potential.     

野生哲罗鱼的采捕及运输技术

两次对采捕的野生哲罗鱼从虎林市虎头镇至宁安市渤安镇进行长途运输。运输时间是9h，运输成活率分别是76％和94．4％。     

温度、湿度和氧气对海湾扇贝无水保活的影响

在实验室条件下,研究了温度、湿度和氧气对海湾扇贝Argopecten irradias无水保活的存活率和失重率的影响,进而研究其无水保活关键技术。对体质量为29~33 g的海湾扇贝采用普通、保湿、充氧和充氧保湿4种处理方式,并分别置于-2、0、4、10、15~18、20~25℃下进行无水保活试验。结果表明：海湾扇贝生态冰温区为-2.8~0℃;随着温度的升高,海湾扇贝的存活率逐渐降低;海湾扇贝在-2、0℃条件下保活效果最好,其次是4℃;保湿组比未保湿组、充氧组比未充氧组的存活率均有显著提高( P<0.05);低温条件下,保湿充氧处理的海湾扇贝存活率显著高于保湿组和充氧组(P<0.05),保活效果最好,保活10 d后其存活率依然达95%以上;低温无水条件下,采用保湿充氧处理的海湾扇贝失重率较小。研究表明,温度、湿度和氧气对海湾扇贝无水保活有较大影响,在-2~4℃的低温条件下采用保湿充氧处理方式对海湾扇贝进行无水保活,效果最佳。     

Influence of feeding ratio and size on susceptibility to microsporidial gill disease caused by Loma salmonae in rainbow trout, Oncorhynchus mykiss (Walbaum)

Two trials were designed to quantify the effect of feeding ratio and fish size on the cohabitation transmission of Loma salmonae, the causative agent of microsporidial gill disease (MGD) in salmonids, Oncorhynchus spp. To evaluate the effect of feeding ratio on disease onset, groups of 45 rainbow trout, O. mykiss (Walbaum) (RBT), were fed daily at 1% (low), 2% (medium) or 4% (high) of the fish biomass in the tank. There were three tanks at each feeding level: two tanks were exposed to the pathogen and one was a control. For the second objective, 300 RBT were separated into seven tanks so that the weight classifications were small (17-23 g), medium (32-38 g) and large (57-63 g). Each size class was done in duplicate with one control tank containing medium-sized fish. Separately for each trial, on day 0 post-exposure (PE) five highly infectious RBT were added to each tank (not including the control tanks) to begin the cohabitation exposure period. Beginning on day 21 PE and continuing biweekly until days 70 and 77 PE for the feeding and fish size trials, respectively, each fish was evaluated for visible branchial xenomas to determine disease onset time. Using survival analysis, the survival curves for the low, medium and high feedings were not significantly different from each other. However, there were significant differences amongst the small, medium and large weight classes in the size trial. The median numbers of days to the development of branchial xenomas was 31, 38 and 42 for small, medium and large size fish, respectively. On any given day, a medium or large sized fish had a hazard ratio for developing branchial xenomas of 0.66 and 0.63, respectively, compared with a small fish. In addition to host species and host strain differences, fish size is now considered a host risk factor for the development of MGD.     

The potential of temporary shelters to increase survival of the endangered Mexican axolotl

1. Amphibian populations worldwide are in decline. Proactive conservation techniques such as translocations into created and restored wetlands have gained popularity in recent years but may fail owing to high predation and low environmental adaptability.
2. The Mexican axolotl (Ambystoma mexicanum), affected by rapid urbanization, is now possibly extinct in the wild despite millions living in captivity throughout the world.
3. The aim of this study was to explore whether ponds from an artificial wetland can function as temporary shelters for a viable population of axolotls that could be re-introduced into their native ecosystem in Xochimilco once it is restored.
4. Egg-laying and hatching of 11 unique axolotl pairs placed into reproductive enclosures and larval survival to 7 weeks and up to 12 months were examined. Physicochemical and biological parameters were estimated and compared among ponds.
5. The results from this study are encouraging as they suggest that two ponds have adequate conditions for axolotls to reproduce and for larvae and juveniles to survive.

     

牙鲆"鲆优2号"不同养殖地点生长和存活性状的基因型与环境互作分析

为比较牙鲆"鲆优2号"在不同养殖地区的生长和存活性能,实验利用连续多代对生长性状和抗迟缓爱德华氏菌病性状遗传参数评估和基因组选择的结果筛选出的亲本,建立28个"鲆优2号"家系,在河北(Site 1)和山东(Site 2)进行对比养殖试验,利用混合线性动物模型对生长和存活性状进行了基因型与环境互作分析。Site 1和Site 2的平均日增重分别为1.5和1.2 g/d,养殖成活率分别为81.4%和82.2%,"鲆优2号"在两个养殖地点的生长和抗病性能均表现优异。不同养殖环境间收获体质量和存活性状的遗传相关分别为0.57(<0.7)和0.82(>0.7),说明不同养殖环境间收获体质量存在显著的基因型与环境互作效应,但是不同养殖环境间存活性状的基因型与环境互作效应不显著。研究表明,牙鲆"鲆优2号"新品种在不同养殖地点的生长和存活性能均表现良好,为保证良好的推广效果,需要对牙鲆的制种方案进一步优化,针对不同的养殖地区进行"鲆优2号"苗种生产,或培育具有普适性的"鲆优2号"苗种,保证在不同养殖环境下的快速生长和高存活率优势。