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51.
王志平 《河北渔业》2011,(3):45-47,50
水产养殖专业英语是为了适应社会经济发展而为学生开设的一门考查课,其目的是让学生掌握一种获取更多资料和信息的语言工具.然而,我国至今没有一本适合普通高职院校学生的专业英语教材.根据自身教学实践,本文从教学内容选择及教学手段改革两方面进行了细致深入的阐述,希望对我国水产养殖专业英语或其他学科专业英语的课程教学改革有所启发.  相似文献   
52.
本研究由浅海网箱区富营养沉积物经多步富集和筛选获得高效复合生态净化菌群,对浅海养殖区的有机物、氨氮和亚硝酸氮有明显去除效果.研究了不同条件对复合菌液去除养殖水体中氨氮、亚硝酸氮和有机物能力的影响,并确定了最佳净化条件.结果表明,复合菌添加量、葡萄糖添加量,处理时间、温度、pH和盐度对复合菌的去除效果均有影响,实验条件确定为复合菌的添加量为3%、处理时间为4 d、温度为30±2 ℃、pH值为8.1±0.2、葡萄糖添加量为2 g/L和盐度为(30±10) g/L 时,去除效果达到最佳,此时氨氮、亚硝酸氮和溶解有机物的去除率可分别达到79.1%、85.2%和88.7%.  相似文献   
53.
During the masculinization of Nile tilapia, Oreochromis niloticus, the effect of a homeopathic complex (containing Chamomilla, Quina, and sulphur) was evaluated based on survival, performance, gills and liver integrity, and parasitism. Group fed with basal diet + 17 alpha-methyltestosterone (control) showed low survival (40.02%), while the group that additionally received homeopathy and the group that received sucrose (vehicle) showed 73.7% and 87.7% survival, respectively. The growth performance of the group that received homeopathic and the control group was significantly higher than that of the group that received only sucrose. Still, fish that received the homeopathic complex showed higher branchial and hepatic integrity as compared to the other groups. The homeopathic complex contributes to a greater survival of fish in addition to maintaining satisfactory growth. Furthermore, homeopathy contributes to the improvement in gill and liver integrity of the Nile tilapia larvae.  相似文献   
54.
The introduction of non‐indigenous plants, animals and pathogens is a pressing global environmental challenge. Although not all introduced species become established and the fraction of those that do often have little appreciable effect on their new ecosystems, many others exert significant ecological, evolutionary and economic impacts. Stimulating further debate, Gozlan [Fish and Fisheries (2008) Vol. 9, pp. 106–115] argued that the majority of intentional freshwater fish introductions associated with aquaculture (fish species providing societal benefits) have not been reported as having an ecological impact. We find little to argue with his suggestion that low risk of ecological impact coupled with high market value encourages further introductions. But do we have an adequate understanding of the ecological risks associated with fish introductions to support such decisions? Indeed, resource managers and decision makers require some scientific knowledge to support their management actions; without this information, a precautionary approach is the only sensible course of action. The precautionary approach implies that the lack of scientific certainty is reason enough for postponing intentional introduction of non‐native species to avoid potentially serious or irreversible harm to the environment. Here, we suggest that we actually know very little about ecological impacts associated with fish introductions and that it would be therefore wholly inappropriate to equate a lack of data with a conclusion of ‘no impact’. We discuss four major challenges for enhancing the assessment of risks posed by non‐native freshwater fishes in the face of scientific uncertainty and highlight research opportunities and some alternative approaches for confronting these challenges in the future.  相似文献   
55.
中间培育是凡纳对虾(Penaeus vannamei)养殖的重要阶段,投喂率是影响此阶段养殖成效的重要参数。本研究开展为期30 d的养殖实验,研究3组投喂率(投喂率分别为体重的5%、7.5%、10%,分别命名为T5、T7.5和T10)对凡纳对虾中间培育养殖水质、微生物群落结构、非特异性免疫指标及生长性能的影响。实验期间,水体pH、盐度、温度及溶解氧均保持在适宜对虾生长的范围内。结果显示,随着实验进行,总氨氮(TAN)、亚硝态氮(NO2–-N)和化学需氧量(COD)浓度出现上升趋势,实验结束时,其浓度随投喂率升高呈现显著差异:T10>T7.5>T5。微生物群落结构分析表明,养殖水体的微生物群落丰富度和多样性随投喂率升高呈下降趋势,不同投喂率的优势门类均为变形菌门(Proteobacteria, 50.36%~67.53%)和拟杆菌门(Bacteroidetes, 12.09%~67.53%);在属水平上,对凡纳对虾有害的弧菌(Vibrio)相对丰度在T10组最高(37.33%)、T5组最低(0.13%);对其有益的假交替单胞菌(Pseudoalteromonas)相对丰度在T10组最低(0.28%)、T7.5组最高(9.78%)。凡纳对虾肝胰腺的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、酸性磷酸酶(ACP)和碱性磷酸酶(AKP)活性在T10组最低、T7.5组最高(P<0.05)。T7.5和T10组对虾的体长和体重均显著大于T5组(P<0.05),但T7.5和T10组之间无显著差异(P>0.05),投喂率与存活率呈负相关,且3组间存在显著差异(P<0.05)。利用因子分析对非特异性免疫指标和生长指标进行综合评价,结果表明,T7.5组得分最高,为0.92,凡纳对虾中间培育的投喂率在7.5%左右为宜。  相似文献   
56.
[目的]为了确定南方浒苔(Ulva meridionalis)对水产养殖废水的净化效率、最适藻体密度和最佳处理时长。[方法]实验以模拟水产养殖废水为藻体培养液,设置0.5、1.0、1.5、2.0、2.5 g/L(实验组)和0 g/L(对照组) 共6个藻体密度梯度,培养于bluepard生化培养箱内,在第0, 12, 24,36,48,60,72 h测定藻体培养液中NH4+-N、NO2--N、NO3--N、PO4--P的浓度。[结果]结果显示,南方浒苔对水产养殖废水具有显著的净化效果(P<0.05),其中净化养殖废水最适藻体密度为2.5 g/L。在南方浒苔最适藻体密度下有效净化水产养殖废水中NH4+-N、NO2--N、NO3--N、PO4--P时最佳处理时长分别为24、60、48、72 h,其去除率分别可达96.02%、51.83%、80.85%、97.67%。同时,南方浒苔对不同形式无机氮的吸收效率会受到水产养殖废水中不同氮源组成的影响,具体表现为先吸收 NH4+-N再吸收NO3--N 最后吸收NO2--N。[结论]研究表明,藻体密度为2.5 g/L的南方浒苔在水产养殖废水中处理72 h对废水中氮磷净化效果最佳。[意义]本研究可为生物净化水产养殖废水提供数据支持。  相似文献   
57.
流沙湾是中国海水珍珠“南珠”的主产区和广东省重要的贝类养殖区。为评估湾内养殖活动的环境效应,于2015~2016年对流沙湾海区进行了夏(8月)、秋(11月)、冬(2月)、春(5月) 4个季节的浮游植物和海水理化因子调查。共检出浮游植物171种,包括硅藻门43属122种、甲藻门 10属44种、蓝藻门2属2种、金藻门2属2种和裸藻门1属1种。流沙湾内湾浮游植物细胞丰度为(0.05~79.04)×104个/L,夏季>春季>秋季>冬季,且夏季丰度远大于其他三季,内湾和外湾差异不显著。春季须状角毛藻(Chaetoceros crinitus)、红海束毛藻(Trichodesmium erythraeum)和明壁圆筛藻(Coscinodiscus debilis)为主要优势种,夏季优势种主要为中肋骨条藻(Skeletonema costatum),秋季优势种主要为拟弯角毛藻(Chaetoceros pseudocurvisetus)、奇异棍形藻(Bacillaria paradoxa)、洛氏角毛藻(Chaetoceros lorenzianus),冬季主要优势种为威氏圆筛藻(Coscinodisus wailesii)、柔弱根管藻(Rhizosolenia delicatula)、岛脆杆藻(Fragilaria islandica)。其中,奇异棍形藻为春、秋、冬季的优势种,红海束毛藻为春、夏、秋季的优势种。冗余分析表明,流沙湾浮游植物优势种在春季与水温和氨氮密切相关,夏季受透明度显著影响,而在秋、冬季受亚硝酸氮含量影响显著。流沙湾不同养殖区的浮游植物多态性和丰度有明显季节差异。与2012年相比,流沙湾外湾的养殖覆盖率提高了近50%,内湾的珍珠贝养殖减少了近90%,养殖品种、规模和分布格局都发生了明显变化,目前流沙湾的浮游植物群落特征正是对其变化的一种响应。夏季鱼类网箱养殖提高了水域营养盐水平并降低了浮游植物多样性。大规模的扇贝养殖则导致了扇贝养殖区浮游植物丰度的降低。  相似文献   
58.
中草药及其配伍对嗜水气单胞菌的抑菌作用   总被引:4,自引:0,他引:4       下载免费PDF全文
采用二倍稀释法测定了86种中草药对嗜水气单胞菌Aeromonas hydrophila的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),并采用正交试验法研究了对嗜水气单胞菌具有较强抑制作用的中草药配伍。结果表明,五倍子、五味子和乌梅对嗜水气单胞菌的抑制作用最强,最小抑菌浓度和最小杀菌浓度均为12.5mg/ml,可作为防治水产养殖动物嗜水气单胞菌病害的首选中草药。正交试验结果表明,儿茶、五倍子、五味子和乌梅4种药分别以4∶2∶4∶1和1∶2∶2∶4的比例配伍时对嗜水气单胞菌具有最佳抑菌和杀菌作用。  相似文献   
59.
Fish stress and mortality can be significant problems in both capture and culture operations. In addition to inexpensive and real-time metrics, ones that are simple to use are also desirable for measuring fish stress and predicting mortality. Current methods to define stress rely on expensive, laboratory-based measurements of changes in fish pathology such as disease, necropsy and histology, in physiology such as plasma cortisol, lactate, glucose and ions and in complex behaviour determined from swimming, feeding and predator evasion. All of these methods are often not rigorously linked to fitness outcomes. An alternative is to observe reflex impairment as a direct sign of stress which can be easily and rapidly measured in free swimming or restrained fish responding to peripheral stimuli such as gravity, light, sound and touch. Reflex impairment is correlated with stress and mortality outcomes, eliminating the need for prolonged holding or monitoring of fish. A few examples of reflexes that may be impaired include orientation, startle responses, fin erection, body flex upon restraint, operculum and mouth clamping or gaping, gag response and vestibular–ocular response. Reflex impairment combines the effects of stressors and their interactions and is not dependent on fish size, motivation states and acclimation which make it a consistent sign of stress across a wide range of stressor types and fish ages. Use of reflex impairment to measure stress and predict mortality would significantly improve monitoring of fish health and welfare in many types of field operations such as commercial and recreational fishing, aquaculture, live transport, stock enhancement and tagging.  相似文献   
60.
夏季高温时,养殖水体水华现象频繁发生,给养殖业带来巨大的损失。常见水生植物释放的活性物质在低浓度下可以起到抑藻作用,对藻类调控具有重要意义。本研究采用实验室静态模拟方法,取养殖池塘暴发蓝藻水华的水体,与沉水植物金鱼藻(Ceratophyllum demersum)及篦齿眼子菜(Potamogeton pectinatus)进行共培养,研究这2种沉水植物对养殖水华水体营养水平、藻类生长、藻类结构及浮游藻类生物多样性的影响。结果显示,金鱼藻和篦齿眼子菜可显著降低水华水体氮、磷等营养水平(P<0.05);金鱼藻和篦齿眼子菜可有效抑制水华蓝藻(Cyanobacteria)生长,尤其对颤藻和微囊藻(Microcystis sp.)效果显著(P<0.05),且篦齿眼子菜对水华蓝藻抑制效果更为显著。实验结束时,篦齿眼子菜培养组藻密度下降93.6%,生物量下降98.9%,叶绿素a含量下降60.5%;金鱼藻培养组藻密度下降72.5%,生物量下降86.8%,叶绿素a含量下降54.3%;金鱼藻和篦齿眼子菜的存在可促进养殖水体浮游藻类生物多样性增加,且金鱼藻提高浮游藻类生物多样性效果更显著。金鱼藻培养组浮游藻类生物多样性升高98.4%,篦齿眼子菜培养组浮游藻类生物多样性升高50.3%。本研究结果可为未来生态养殖提供理论依据和参考。  相似文献   
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