海水控制罗非鱼池塘中裸藻试验

用5‰、10‰、20‰及32‰4种盐度的海水,对罗非鱼池塘中的裸藻进行了杀灭试验。5‰盐度,64．8h以上可对裸藻的活动产生抑制作用;10‰盐度,72h可杀灭部分裸藻;32‰盐度,48h以上可完全杀灭裸藻。在罗非鱼养殖池塘中,控制裸藻宜用10‰盐度,处理时间55一146h。     

一种红褐色裸藻水华的研究

1990年春夏之交，在沁阳市鱼种场的成鱼池中见到一种红褐色(酷似铁锈色)水华。1986年，该场曾用硫酸铜在亲鱼池药杀藻体，造成二百多尾鲢，鳙及草鱼死亡。几年来，这种水华一直威胁着鱼类的生存。为探明这种水华，从当年5月份起对形成这种水华的红褐色裸藻(Euglena sp．)的形态构造，生物学性、水华特征、生态条件、变化规律及其与鱼类的关系等进行了研究，简报如下。     

用裸藻对饵料生物进行营养强化

<正> 1 前言 近20年来,鱼类营养需要的研究得到了飞速的发展,特别是脂肪酸中的高度不饱和脂肪酸(n-3HUFA)的重要性已被普遍认识。仔鱼期不可缺少地投喂饵料生物也说明了n-3HUFA的供给是非常重要的,所以目前所有的种苗生产都用海水小球藻和市售的营养强化饲料对饵料生物进行营养强化。 在天然的n-3HUFA中,二碳五烯酸(EPA)和二十二碳六烯酸(DHA)占大部分。最近在真鲷、大甲鲹、鰤鱼、日本对虾的饲养中比较了上述两种必需脂肪酸的效果。其     

通过纤细裸藻强化生物饵料的营养

通过纤细裸藻强化生物饵料的营养林雅宏，户田享次著对鱼类营养需求的研究，近２０年取得显著进展，特别是必需脂肪酸中的ｎ－３高度不饱和脂肪酸（ｎ－３ＨＵＦＡ）的重要性已被广泛认识。ｎ－３ＨＵＦＡ的供给，在仔稚鱼期尤为重要。现在大部分苗种生产单位都用微绿球藻...     

纤细裸藻在水产饵料中的开发利用

纤细裸藻（Ｅｕｇｌｅｎａ ｇｒａｃｉｌｉｓ）是一种介于动、植物两者之间的中间性生物，具有动、植物性质的蛋白质组成。但因对其被水产动物消化利用程度上的分歧，以往一直未将其当成饵料生物来开发利用。近几年来日本等国产广泛地用作仔鱼和稚鱼的饵料，作为专利产品进行生产和销售。本文介绍了纤细裸藻的生物学特征、培养技术、生化成分及作为鱼类（虹鳟和真鲷）饵料的效果等概况。     

一种水华裸藻的显微观察

采用显微观察方法研究了一种在鱼池中经常形成水华的裸藻（Euglena SP.)的形态特点，包括藻体外形、裸藻红素、鞭毛、眼点、色素体及副淀粉等形态结构，并探讨了这种裸藻的繁殖方式。     

纤细裸藻对5种抗生素的胁迫响应

裸藻(Euglena)是一种重要的资源微藻,含有丰富的氨基酸、不饱和脂肪酸、维生素和裸藻糖等营养物质,并且裸藻没有细胞壁,其营养成分相对于其他藻类更容易被人体、水产动物吸收,开展裸藻集约化培养,对优化养殖环境具有十分重要的意义。为了研究裸藻的无菌化养殖,实验生态条件下,研究了不同浓度的5种抗生素(遗传霉素、氯霉素、青霉素、土霉素和链霉素)胁迫对纤细裸藻(Euglena gracilis)细胞密度及叶绿素a水平的影响。结果表明,在遗传霉素、土霉素和链霉素胁迫作用下,裸藻细胞密度显著降低(P0.05),低于25μg/m L的遗传霉素即可对裸藻生长与叶绿素a合成产生抑制,200μg/m L的土霉素和25μg/m L、50μg/m L的链霉素对裸藻叶绿素a合成有一定的促进作用;氯霉素和青霉素对裸藻生长有一定的促进效应,200μg/m L的青霉素可以显著提高纤细裸藻的细胞密度和叶绿素a水平(P0.05)。实验结果说明纤细裸藻对遗传霉素、土霉素和链霉素的敏感性较强,而氯霉素和青霉素可以作为纤细裸藻无菌系建立的备选抗生素,研究结果可为纤细裸藻的基因工程选择标记和无菌培养体系的建立提供参考。     

高温下纤细裸藻培养中出现的问题及解决办法

水温持续在２９℃叶,纤细裸藻（Ｅｕｇｌｅｎａｇｒａｃｉｌｌｓ）培养液中会产生大量的异养性细菌,使藻体失去活力甚至死亡,作者利用常见土霉素,氯霉素,庆大霉素抑制纤细裸藻培养液中细菌结果证明土霉素的效果明业,氯霉素次之。     

纤细裸藻及其对轮虫、卤虫的营养强化

前言 近二十年来,有关鱼类营养需求的研究,取得了显著的进展,特别是已普遍认识到作为必需脂肪酸的n—3高度不饱和脂肪酸(n—3HUFA)的重要性。尤其是在仔鱼期中,生物饵料的投喂不可缺少,n—3HUFA的提供十分重要。现在几乎所有的种苗生产工艺中,都是采用微绿球藻Nannochlorapsis或市售的营养强化饲料,对生物饵料进行营养强化。 作为天然存在的n—3HUFA,绝大部分是EPA(廿碳五烯酸)和DHA(廿二碳六烯酸)。最近,在真鲷、缟鲹、鰤鱼和日本对虾等,对它们二者的必需脂肪酸效果进行比较。其结果,     

硫酸铜、敌百虫、聚维酮碘对吉富罗非鱼的急性毒性及组织病理学研究

为评估水产养殖中常用药物——硫酸铜、敌百虫、聚维酮碘的合理给药量及其安全性,以及对吉富罗非鱼(Oreochromis niloticus)的毒害作用,采用静态急性毒性试验法,研究了这3种药物对吉富罗非鱼鱼苗的急性毒性及组织病理影响。结果表明,硫酸铜对吉富罗非鱼24、48和96 h的半致死浓度(LC50)分别为13.715、10.351和5.896 mg·L^-1,安全浓度(SC)为1.769 mg·L^-1;敌百虫对吉富罗非鱼24、48和96 h的LC50分别为43.036、25.887和16.689 mg·L^-1,SC为2.810 mg·L^-1;聚维酮碘对吉富罗非鱼24、48和96 h的LC50分别为10.509、9.301和8.674 mg·L^-1,SC为2.190 mg·L^-1。组织病理学研究结果显示,硫酸铜暴露可造成鳃丝轮廓模糊不清、鳃组织空泡化,肝组织空隙变大、空泡化、细胞核萎缩,脑组织神经纤维出现破损、细胞凋亡,肾小管结构破坏、核膜破损;敌百虫暴露...     

Supplemental Feeding of Tilapia in Fertilized Ponds

The addition of feed to fertilized fish ponds was evaluated by adding feed alone, feed plus fertilizer, or fertilizer alone to nine ponds stocked with Nile tilapia Oreochromis niloticus . Two experiments were conducted. The first had 500 fish per 250 m² pond in 3 treatments: ad-libitum feeding; fertilizer only; or fertilizer and ad-libitum feeding. The second experiment had 5 treatments with 750 fish per pond ad-libitum feed only; fertilizer only; or 0.25, 0.50, and 0.75 satiation ration plus fertilizer. Ponds in Thailand were maintained for 155–162 d, during which chemical and physical properties were monitored. In experiment 1 tilapia growth was highest in feed only ponds, and lowest in fertilizer only ponds. Net yield did not differ significantly among treatments, due to variation in survival. In experiment 2, tilapia growth was lowest in fertilizer only ponds, intermediate in 0.25 ration ponds, and highest in 0.50, 0.75, and ad-libitum ponds. The latter treatments were not significantly different. Multiple regressions for each experiment indicated only 47–87% of the variance in growth was explained by feed and fertilizer input, while 52–89% of the variance in yield was explained by those factors. For both experiments combined, 90.3% of the variance in growth was explained by feed input, fertilizer input, alkalinity, and total inorganic nitrogen concentration. For yield, R ² was 0.888 and the regression included feed input, pH, and number of low dissolved oxygen events. Experiment 1 appeared to approach carrying capacity near the end, while no reduction in growth occurred in experiment 2 at higher fish density and biomass. Reductions in growth in experiment 1 were not correlated with declining water quality late in the grow out. Combinations of feed and fertilizer were most efficient in growing tilapia to large size (500 g) compared to complete feeding or fertilizing alone.     

罗非鱼池塘套养南美白对虾生态养殖试验

为了探索一种适合在咸淡水资源丰富地区发展的生态养殖模式,在广西防城港市利用河海交汇处的高位池进行了大规格罗非鱼池塘套养南美白对虾的试验.结果显示:南美白对虾平均单产220 kg/亩,罗非鱼平均单产670 kg/亩,平均利润达5550元/亩.试验结果表明:罗非鱼养殖池套养南美白对虾可充分利用养殖水体的空间,降低对虾的养殖成本,有效控制虾病的发生和传染,提高养殖经济效益.     

Comparison of Tilapia Monoculture and Carp Polyculture in Fertilized Earthen Ponds

A comparison of a monoculture of Nile tilapia Oreochromis niloticus and a polyculture of carps (silver carp Hypophthalmichthys molitrix; rohu Labeo rohita; and mrigal Cirrhinus mriga la; ratio 4:3:3) was carried out in 200-m² earthen ponds fertilized with cattle manure and supplemented with inorganic fertilizer at 3-kg nitrogen and 1.5-kg phosphorus/ha per day. A control treatment of a tilapia monoculture without fertilizer inputs was included to assess the effect of pond basal fertility. Net yields of 23.5 kg/pond per 112 d (3.8 t/ha per 1 yr) in the tilapia monoculture and 19.2 kg/pond per 112 d (3.1 t/ha per yr) in the carp polyculture were not significantly different; net yields from unfertilized tilapia monoculture ponds were negative. In the carp polyculture, silver carp was the dominant species at harvest contributing 73% of the total net fish production compared to 9% and 19% by rohu and mrigal, respectively. Water quality data suggested that tilapia yields could have been further improved by increasing fertilization rate but that critical dissolved oxygen concentration constrained this option for carp polyculture.     

Effects of Stocking Density on Growth of Tilapia nilotica Cultured in Cages in Ponds

Reported maximum carrying capacities of Tilapia nilotica reared in cages are Iow ranging from 10 to 70 kg/m³. This may be related to total numbers of caged fish reared in a body of water and not simply density per cage volume. An experiment was conducted to demonstrate such effects.
Sixteen cages in a 0.77 ha pond were stocked with T. nilotica at either 250, 500, 750, or 1,000 fish/cage for a total of 12,987 fish/ha. One cage in each of four 0.13 ha ponds was stocked with either 250 or 1,000 fish/cage for a total of 1,923 or 7,692 fish/hectare, respectively. Fish were fed a 32% protein diet at equal rates for 169 days. In the 0.77 ha pond, yield per cage was positively correlated with stocking density, while individual mean weights were negatively correlated with stocking density. However, among equal densities per cage between ponds, fish in the 0.13 ha ponds gained about 26% more than in the 0.77 ha pond. An interaction of the effects of density per cage volume and per pond area may have occurred.     

Impact of Copper Sulfate on Plankton in Channel Catfish Nursery Ponds

Many fish culturists are interested in applying copper sulfate pentahydrate (CSP) to channel catfish, Ictalurus punctatus, nursery ponds as a prophylactic treatment for trematode infection and proliferative gill disease by killing snails and Dero sp., respectively, before stocking fry. However, copper is an algaecide and may adversely affect phytoplankton and zooplankton populations. We evaluated the effects of prophylactic use of copper sulfate in catfish nursery ponds on water quality and phytoplankton and zooplankton populations. In 2006, treatments of 0 mg/L CSP, 3 mg/L CSP (0.77 mg/L Cu), and 6 mg/L CSP (1.54 mg/L Cu) were randomly assigned to 0.04‐ha ponds. In 2007, only treatments of 0 and 3 mg/L CSP were randomly assigned to the 16 ponds. Ponds treated with CSP had significantly higher pH and significantly lower total ammonia concentrations. Treatment of both CSP rates increased total algal concentrations but reduced desirable zooplankton groups for catfish culture. CSP has been shown to be effective in reducing snail populations at the rate used in this study. CSP treatment also appears to be beneficial to the algal bloom, shifting the algal population to green algae and increasing total algal biomass within 1 wk after CSP treatment. Although zooplankton populations were adversely affected, populations of important zooplankton to catfish fry began rebounding 6–12 d after CSP treatment. Therefore, if CSP is used to treat catfish fry ponds of similar water composition used in this study, fry should not be stocked for about 2 wk after CSP application to allow time for the desirable zooplankton densities to begin increasing.     

Infection of Tilapia Oreochromis sp. by Vibrio vulnificus in Freshwater and Low-salinity Environments

The first isolation of Vibrio vulnificus in southern Taiwan from hybrid tilapia Oreochromis sp. raised in freshwater and brackish water environments is documented in this report. The infection was only found in fish in ponds where the salinity was less than 10 ppt. Tilapia raised in water of higher salinities in the same region were not affected. Grossly visible signs of infection included dark coloration, lethargy, and external hemorrhage and ulceration of the skin. The most prominent internal signs of infection included splenomegaly and severe hemorrhagic lesions in the liver. Septicemia was documented in moribund fish. All bacterial isolates from moribund fish were tested by polymerase chain reaction, using V. vulnificus hemolysin/cytolysin gene‐specific primers. Sequence data from the 16S ribosomal RNA gene suggest that these isolates were V. vulnificus. The isolates were indole and mannitol positive, characteristics shared by human clinical isolates and isolates from freshwater European eel, Anguilla anguilla. The isolates from tilapia were unique in that they were negative for ornithine decarboxylase and citrate.     

罗非鱼养殖质量安全控制技术

罗非鱼养殖质量控制参照HACCP的原则。对全养殖过程所有影响成鱼质量安全的潜在危害进行分析，对每个潜在危害发生的可能性及其严重程度进行评价，找出影响罗非鱼质量安全的具有风险性和严重性的显著危害，确定养殖过程质量监控关键控制点，制定显著危害的预防措施和关键控制点的关键限值。建立对关键控制点监控的系统，制定纠偏措施，建立验证程序和记录档案。建立起罗非鱼养殖质量安全控制体系进行质量控制．确保影响罗非鱼质量安全的所有危害得到监控．产出的罗非鱼完全符合无公害水产品和加工出口原料要求。     

用硫酸铜防治鱼类小瓜虫病的探讨

对硫酸铜防治小瓜虫病的效果众说不一。有人认为,用硫酸铜杀灭小瓜虫不但无效,反而促使其繁殖。作者认为,造成这种情况的主要原因是用药量未达到小瓜虫的致死浓度（Ｍｉｎ．ＬＣ８８≥０．２８８ｍｇＣｕ＋＋Ｌ－１）,其次是硫酸铜的药物浓度往往受到环境（水的温度、硬度、ｐＨ值、有机物含量）的影响,从而导致药效减弱。因此,在实际使用时须作必要的计算,以求得合理的用药量。采用螯合铜或复配增效剂是提高铜盐杀虫效果的好办法     

Comparative Performance of Four Strains of Nile Tilapia (Oreochromis niloticus) in Brackish Water Ponds in Indonesia

Four selectively bred strains of Nile tilapia (Oreochromis niloticus) were evaluated for production in brackish water ponds in Indonesia. Survival to 124 days was relatively low for all four strains (39%–48%), and growth during the later stages of the trial was poor (SGR < 1.5 %/day) due to water quality deterioration in the pond. Although the ‘Red’ tilapia strain demonstrated the best production parameters, red-colored tilapia bring lower prices in both our test markets (South Sulawesi and Aceh provinces). Of the four strains, the genetically enhanced supermale Indonesian tilapia?×?genetic improvement of farmed tilapia (GESIT×GIFT) cross provided the best economic return.