Bacteriological and physico-chemical analysis in a bivalve hatchery: Techniques and preliminary results

The bacteriological and physico-chemical methods used in the survey of a bivalve hatchery are presented and the preliminary results discussed. It was concluded that food, through its contribution of nutrient salts and bacteria, had a major influence on larval culture.The physico-chemical characteristics of sea water were not modified by heat or filtration treatments. The bacteria were not always eliminated from sea water by filtration and were sometimes more numerous after treatment.In effect, the larvae were raised in an artificial environment subject to marked fluctuations which had mechanical and biological origins. This survey must be complemented by a qualitative bacteriological study and the establishment of critical values for the physico-chemical parameters involved in the culture of these bivalve larvae.     

天津周边海域表层水体理化要素分布特征和水质评价

通过对天津周边海域表层水体的一些理化要素进行调查,得到化学需氧量(CODMn)、活性磷酸盐(PO34--P)、氨氮(NH4+-N)、亚硝酸盐氮(NO2--N)及硝酸盐氮(NO3--N)含量从离岸近的海域向外海方向递减。水温、pH值、盐度的变化趋势则正好相反;在此次调查期间,天津周边海域海水中无机氮的主要存在形式为NO3--N和NO2--N;相关性分析表明,盐度与化学需氧量、活性磷酸盐、无机氮、亚硝酸盐氮在p=0.01水平上均呈极显著负相关;活性磷酸盐与无机氮、NO2--N和NH4+-N含量均在p=0.01水平上呈极显著正相关;由N/P比和E值的平面分布图可以得到,沿岸N/P比最低,离岸越远的地方N/P比越高。E值的平面分布恰恰相反。北塘附近海域依然是富营养化最严重的区域;本调查海域主要是磷限制,无机氮仍然是此海域的首要污染因子,其次是化学需氧量。     

Ultraviolet light disinfection of shellfish hatchery sea water: I. Elimination of five pathogenic bacteria

Filtered sea water was seeded with one of five oyster-pathogenic bacteria to obtain a final concentration of 10⁵ cells/ml. UV irradiation at a dose of 93 312–155 520 μW s^?1 cm^?2 rendered the contaminated sea water safe for rearing fertilized eggs of Crassostrea virginica. Fertilized oyster eggs were reared until the larvae began to set in filtered, UV-irradiated sea water and in filtered, non-UV-treated sea water. The data suggest that when a pathogenic bacterium is present the potential for disease is much greater in non-UV-treated sea water.     

福建近海若干个拟投放深水网箱海湾理化环境调查与评估

根据2000和2001年福建主要港湾调查所获得的海洋水文和海洋化学环境资料，对拟投放深水抗风浪网箱海域的海水理化因子作了较详细的分析研究，以评估该海域是否适合于投放深水网箱。结果表明，三都澳、官井洋、东吾洋、罗源湾、福清湾、兴化湾，湄州湾和东山湾水深在25m以上，湾外有岛屿屏障，环境隐蔽、水流稳定，水温、盐度和透明度有显著的季节变化，pH和DO符合国家渔业水质标准，COD一般符合一类海水水质标准，局部海域达到二类海水水质标准，IN、PO3-P一般符合二类海水水质标准，在秋季有些港湾达到三类海水水质标准。从理化环境的角度分析，上述海湾可作为投放深水网箱之场所。     

刺参育苗系统中的敌害生物——玻璃海鞘的药物杀除试验

10种渔药对玻璃海鞘Ciona intestinalis的急性毒性试验结果表明,硫酸锌(≤3 mg/L)、碳酸氢钠(≤2.5%)、茶皂素(≤6.7 ml/L)、氯氰菊酯(≤0.2 ml/L)、精制敌百虫粉(≤4 mg/L)、敌百虫*辛硫磷粉(≤3 mg/L)和高锰酸钾(≤5 mg/L)对玻璃海鞘无致死作用.在24 h内,硫酸铜浓度≥1 mg/L、灭鞘灵(MQL)浓度≥5 mg/L和自制大蒜素复方药物灭鞘散(MQS)≥15 mg/L时,对玻璃海鞘有100%的致死作用,其24 h的LC50值分别为0.58、3.33和10.80 mg/L.硫酸铜浓度≥1 mg/L时,稚参在3 h内吐肠率达80%以上,对刺参能造成严重的生理伤害.因此,硫酸铜不适合在生产实践中使用.MQS浓度为20 mg/L或MQL浓度为10 mg/L对稚参的毒性实验表明,药物浸泡稚参96 h仍活动正常,对生存没有任何影响.因此,MQS和MQL可视为刺参养殖系统中杀灭玻璃海鞘的有效药物,分别采用15 mg/L和5 mg/L的浓度,药浴24 h后换水即可完成.     

大连湾海域水质状况及污染趋势分析

选用2011年大连湾附近海域的监测数据,分别采用不同的评价方法对大连湾海域的水质现状加以评价。并依据2007—2011年该海域连续五年的监测数据,对其污染趋势加以分析。结果表明:大连湾海域内主要污染物为无机氮,湾内各监测点均处于富营养化状态,受有机物污染严重。陆源排污是该海域受到严重污染的主要原因。五年来除无机磷外其余各因子均有不同程度的污染加重的趋势,其中以石油类的加重趋势最为显著。     

Concentration and detection of Aeromonas salmonicida from hatchery water

Abstract. A method using 1-MDS electropositive filters for the concentration of Aeromonas salmonicida from hatchery water was developed. The procedure consisted of passing hatchery water at ambient pH through the filters followed by the elution of the adsorbed bacteria in a small volume of 3% beef extract solution (pH 10.0). A 300-fold reduction in volume of hatchery water and an average recovery of 35% of the seeded bacteria was achieved.     

南通近岸海域水质现状与趋势分析

根据2005-2010年南通近岸海域的水质监测,对该区域的水质状况和趋势作出分析和评价。结果表明:影响该海域水质的主要污染因子是磷酸盐,部分站位出现无机氮超标。近岸海域水质总体变化基本稳定,部分污染物略呈上升的趋势。     

Migration performance of wild and hatchery sea trout (Salmo trutta L.) smolts—Implications for compensatory hatchery programs

Migration success of hatchery-reared and wild sea trout smolts through the lower stretches and the estuary of a Baltic Sea river were studied. During 3 years, wild and hatchery trout smolts were implanted with acoustic transmitters and released 14 km upstream from the river mouth. In order to monitor their out-migration pattern, acoustic receivers were deployed along the migratory route. Data on number of fish detected and date and time of detections were analysed and the migratory performance of wild and hatchery-reared fish was compared. A significantly higher proportion of wild fish (80%) successfully migrated to the coast compared to fish of hatchery origin (27.5%) and migration was faster in wild smolts. Hatchery fish were larger and had a higher condition factor and lipid concentrations, which are proposed as possible reasons for the poorer migratory performance of the hatchery-reared fish.     

Feasibility of saltwater gradient ponds as a heat supply for hatchery rearing water

Salt gradient solar collector ponds are economically feasible as a source of heat energy for hatchery rearing water. A pond 3 m deep and covering an area of 5000 m² will supply approximately 2800 GJ of energy over a three-month period — enough for a one-year smolt program in an Atlantic salmon hatchery. The cost to construct such a pond is approximately $173,000, or the equivalent of seven years' fuel bills using conventional heating equipment. Although the technology is new and not entirely understood, existing ponds have proven to be relatively problem free and require only minimum maintenance.     

黄河三角洲地区刺参养殖水质变化特点与调控

黄河三角洲地区引进刺参,证明在山东省中西部分沿海实施"东参西养"是可行的,水质变化与调控在刺参养殖过程中起到关键作用,概述了黄河三角洲地区刺参养殖水质变化特点、存在的问题以及影响因素,提出了刺参养殖水质调控和优化措施。     

昌黎县海湾扇贝养殖海域水质调查与评价

根据2018年9月10日对昌黎县海湾扇贝养殖海域的水质调查数据,分析了该海域水体基本理化因子,并采取营养状态质量指数评价法(NQI)、营养状态指数法(E)、有机污染指数评价法(A)及内梅罗环境质量综合评价指数法(P)对水质进行综合评价。结果表明:昌黎县海湾扇贝养殖海域各站位的水温、盐度、pH、DO、COD和DIP含量均符合海湾扇贝养殖水质标准,但是DIN含量严重超标。评价结果显示昌黎县海湾扇贝养殖海域已受到有机污染且水体呈现富营养化,养殖区内比养殖区外情况更为严重,其中N7站位最甚。DIN为该海域主要污染因子。     

Daily change of genetic variability in hatchery offspring of red sea bream during spawning season

ABSTRACT:   In order to assess a daily change of genetic variability during spawning season, hatched larvae of red sea bream sampled on different dates were assayed by polymorphic markers such as microsatellite DNA (msDNA) and mitochondria DNA (mtDNA) control region. Based on the microsatellite loci, the average number of alleles per locus ranged between 13.7 and 18.3. The expected heterozygosities ranged between 0.843 and 0.919. A total of 23 mtDNA haplotypes were detected via digestion of mtDNA D-loop sequences with five endonucleases: Taq  I, Alu  I, Mbo  I, Rsa  I and Hinf  I. Significant fluctuation of genetic variability during spawning season was detected by both types of DNA markers. It was suggested that the genetic variability was maintained by pooling the seed fish collected on different spawning dates in a hatchery.     

Treatment of hatchery wastewater by a sequencing batch reactor process

After settling pretreatment, the primary sludge wastewaters from a fish hatchery were treated in three five-litre bench-scale sequencing batch reactors. The sequencing batch reactors were operated concurrently under the same operating conditions. A cycle of 24 hours was adopted during the course of this study. Two different temperature regimes (22°C and 10°C) were employed, and a range of initial BOD₅ concentrations was treated. The results showed the occurrence of very high reductions in BOD₅ and COD concentrations, and very high removal of ammonia---nitrogen and suspended solids. The average five-day BOD₅ reduction was 98% for high influent concentrations, while the reduction for lower influent concentrations was 95%. The average five-day BOD₅ concentration for the effluents was less than 100 mg litre⁻¹. Nitrification was pronounced after 40 days of reactor operation. Denitrification occurred when the reactors were fed wastewaters with high BOD₅ concentrations, although it was not observed with low influent BOD₅ concentrations or at low temperatures (10°C). The overall treatment efficiency remained very high when the reactors were operated under a low temperature regime (10°C).     

铜合金围栏养殖大黄鱼海域水质综合评价与分析

为了评价铜合金围栏养殖大黄鱼(Larimichthys crocea)海域的水质状况,通过大黄鱼养殖期与非养殖期的4次调查,分析评价了调查海域海水中的p H、溶解氧、铜、锌、无机氮、活性磷酸盐等指标的区域分布、季节变化及污染水平,并利用内梅罗指数对调查海域水体进行了质量综合评价。结果表明:调查海域大黄鱼非养殖时间段的海水综合质量整体上属于清洁或者较清洁状态,大黄鱼养殖时间段的海水综合质量下降,分布趋势是以养殖网箱为高值中心,向外缘逐渐下降。     

Pattern of physicochemical changes in the water during hatching of Indian carp eggs in a Chinese hatchery system

Physicochemical changes in the water were monitored at different hours of embryonic and larval development of Indian carp (Cirrhinus mrigala) eggs in a Chinese hatchery system with 75–85% hatching success. At a water temperature of 29.3°C, mass hatching of the embryos started at about 11–12 h after fertilization and was completed within 4 h. The amount of dissolved oxygen and chemical oxygen demand ranged between 4.8 and 9.63 mg l^?1 and 16.5 and 185.0 mg l^?1, respectively. A marked rise in the concentration of bicarbonate and total hardness of the water after egg transfer into hatching tanks was perhaps due to liberation of Ca²⁺ and Mg²⁺ from the egg mass. A sharp decline in phosphate content during hatching was associated with the building of bones, while the ammonia level was greatly increased due to a high rate of nitrogenous excretion during hatching.     

刺参池塘底栖真核生物DGGE指纹结构与环境理化因子的相关性分析

采用基于18S rDNA PCR-DGGE技术对刺参池塘养殖系统底栖真核生物群落结构与环境理化因子进行分析.结果表明,刺参养殖池塘系统中附着基真核生物DNA指纹图谱均呈现出了丰富的多样性,成参养殖池塘分别获得26、25、25条扩增条带,幼参养殖池塘分别获得20、22条扩增条带;刺参养殖池塘中叶绿素、总磷、总氮、溶氧分别为2.037～5.383 μg/L、0.016～0.039 mg/L、1.863～3.562 mg/L、4.06～6.18mg/L,成参养殖池塘的各项理化指标值均高于幼参养殖池塘.通过指纹图谱和理化因子的聚类分析可以看出,附着基底栖真核生物DGGE指纹图谱与环境中理化因子聚类分析图相吻合,说明不同刺参养殖池塘底栖真核生物群落DNA指纹与养殖环境的理化因子密切相关.本研究通过DGGE技术分析刺参池塘附着基底栖真核生物指纹图谱,进而分析与环境中理化因子的关系,为建立底栖真核生物群落DNA指纹结构与水体理化指标之间的关系提供科学依据.     

Management of a closed brackish water system for high-density fish culture by biological and chemical water treatment

During a 1-year operation of a warm water recycling system (salinity about 8‰) sufficient water quality was maintained under high stocking density conditions using Tilapia and the European eel as potential candidates for intensive farming. The final fish: water ratio was 1 : 23 (or 43.5 g fish per 1 water) for the whole experimental culture unit. The total water volume of the system was about 5 m³. The water treatment unit held 52% of the total volume, whereby 46% was available for fish culture. Combined biological (trickling filter with Hydropack-foil) and chemical (ozonation) water treatment proved to be useful to meet water quality requirements under these rearing conditions. After an initial conditioning period of the biofilter, BOD varied from 4.5 to 6.0 mg O₂/l, ammonium levels were maintained at less than 1 mg/l and nitrite concentrations averaged 1 mg/l. The average efficiency (oxidation rate) of the biofilter for NH₄⁺-and NO₂^?-oxidation was 31% and 13.2%, respectively. The pH was stabilized slightly above 7.0 when a denitrification unit was connected to the system. Nitrate concentration of the system levelled of between 200 and 400 mg/l and was regulated by the addition of an electron donator (first glucose solution, then methanol) to the denitrification unit; the elimination rate averaged 50% with a maximum of 98%. High nitrite levels were avoided by ozone treatment of the recycled water. The accumulation of low-biodegradable substances was also successfully counteracted by ozonation. Fish growth rates of about 30% per month at high stocking densiteis were reached for Tilapia at a fish: water ratio of 1 : 4.6 (217 g fish per 1 water), indicating that a combination of biological water treatment and ozonation supports intensive fish culture in a closed aquaculture system.     

速冻方式对梭子蟹贮藏理化指标和品质的影响

以速冻速度、盐溶性蛋白、ATPase活性、巯基含量、失水率及感官评定为指标,研究采用-50℃液体浸渍、-50℃液氮喷洒、-35℃空气隧道式、-20℃冰柜直接冻结梭子蟹Portunus pelagicus,其肉蛋白质理化指标及品质变化情况。结果表明,用温度记录仪测定液体浸渍速冻最快,其次为液氮喷洒、空气隧道式,最慢为冰柜直接冻结。4种方式速冻的蟹,在冻藏过程中随时间的延长,其肌动球蛋白盐溶性、ATPase活性及巯基含量均呈下降趋势,但低温快速冻处理能降低蟹肉蛋白质冷冻变性的程度,-50℃液体浸渍对梭子蟹品质的保持最好,最差的是一20℃冰柜直接冻结。