疏浚泥浆排放对渔业生产的影响 及其对策研究↑（*）Ⅱ．对鱼苗、鱼种呼吸代谢、血液生化指标和鳃组织结构的影响

以鲫、草鱼、鲢和团头鲂鱼种为材料，研究了疏浚泥浆对这些鱼类的耗氧率、血液学生化指标和鳃组织结构变化的影响。结果表明，在泥浆浓度0．08－1．248g／l范围内、鱼种的耗氧率（Y）与水体含泥量（X）呈线性相关，其关系式为：Y↓（鲫）=0．3324－0．0745X（P＜0．01），Y↓（     

“四大家鱼”对暴发性鱼病的抗病力的种间差异↑（*）

嗜水气单胞菌所引起的暴发性鱼病，是近年来危害我国淡水养殖业的主要病害之一。本文报导草鱼、青鱼、鳙、鲢对该病的抗病力的差异及机理的研究结果。在菌液浓度为６．０×１０￣８ＣＦＵ／ｍｌ（１０°，１０￣（－１），１０￣（－２），１０￣（－３）四个稀释度），注射剂量为０．３ｍｌ／尾时，半数致死生（ＬＤ＿（５０））分别是草鱼１０￣（－０．４８），青鱼１０￣（１．２５），鳙１０￣（－１．３７），鲢１０￣（－２．１９），差异显著（Ｐ＜Ｐ＿（０．０５））。四种鱼的白细胞吞噬百分率存在极显著差异（Ｐ＜Ｐ＿（０．０１）），其中草鱼极显著地（Ｐ＜Ｐ＿（０．０１））强于其他三种鱼。四种鱼的补体替代途径（Ｃ＿３旁路）杀菌力１２小时测定结果的大小顺序是草鱼＞青鱼＞鳙＞鲢，差异显著（Ｐ＜Ｐ＿（０．０５））。草鱼的补体总量极显著地（Ｐ＜Ｐ＿（０．０１））低于鲢、鳙。四种鱼的红细胞Ｃ＿３ｂ受体花环率存在显著差异（Ｐ＜Ｐ＿（０．０５）），顺序为鳙＞鲢＞草鱼＞青鱼。“四大家鱼”对暴发性鱼病的抗病力的种间差异，不仅同它们的免疫力的大小有关，也同它们对特定病原的易感性的大小有关。     

食盐对草鱼血清超氧化物歧化酶和溶菌酶活性的影响

草鱼养殖过程中经常使用食盐药浴，以便在高渗环境下杀死病原体。研究食盐药浴后草鱼代谢酶变化，有助于了解食盐药浴对草鱼机体生理免疫的影响。将草鱼（Ｃｔｅｎｐｈａｒｙｎｇｏｄｏｎｉｄｅｌｌａ）分别暴露于食盐浓度为０、２％、３％、４％水体中浸浴１０ｍｉｎ，然后置入水簇箱中饲养，分别在药浴后１２ｈ、２４ｈ、３６ｈ取样，测定其血清中超氧化物歧化酶（ＳＯＤ）和溶菌酶（ＬＳＺ）活性变化。结果显示，与对照组相比，血清ＳＯＤ活性在１２ｈ时，２％组中显著上升（Ｐ＜０．０５），３％、４％组显著下降（Ｐ＜０．０５）；２４ｈ取样时，２％、３％组中无显著差异（Ｐ＞０．０５），４％组显著下降（Ｐ＜０．０５）；３６ｈ取样时，各组间均无显著差异（Ｐ＞０．０５）；血清ＬＳＺ活性各组间均无显著差异（Ｐ＞０．０５）。食盐能引起草鱼ＳＯＤ活性变化，而对溶菌酶活性影响不大；表明食盐对草鱼不同代谢酶有不同的反应模式，抗氧化酶ＳＯＤ对食盐应激有敏感的生理应答。     

鳜幼鱼窒息点、耗氧率的初步研究

<正>鱼类的窒息点和耗氧率是反映鱼类代谢水平的重要依据。张伟等~([1])研究发现,当溶氧水平从饱和水平下降到1 mg/L时,鲫(Carassius auratus)幼鱼摄食代谢率下降51%,相同温度条件下,南方鲇(Silurus meridionalis)的摄食代谢下降31%~([2])。因此,了解鱼类窒息点和耗氧率对鱼类养殖生产有指导意义。国内对鲤形目中鱼类的耗氧率和窒息点研究起步较早,1955年,陈寗生等首先对鲢(Hypophthalmichthys molitrix)和鳙(Aristichthys nobilis)的耗     

盐度对罗氏沼虾能量代谢和运动能力的影响

为研究盐度对罗氏沼虾(Macrobrachium rosenbergii)能量代谢和运动能力的影响, 设置了 0 (对照)、4、8 和 12 共 4 个盐度胁迫水平, 研究了罗氏沼虾在胁迫 48 h 后的耗氧率、鳃丝和肌肉能量代谢酶活性及其游泳和弹跳能力。结果显示, 耗氧率在盐度升至 4 时并无显著变化(P＞0.05), 但 8 和 12 盐度组的耗氧率显著高于对照组(P＜0.05)。 鳃丝己糖激酶(HK)、磷酸果糖激酶(PFK)和乳酸脱氢酶(LDH)活性在不同盐度条件下并无显著变化(P＞0.05), 但鳃丝丙酮酸脱氢酶(PDH)和细胞色素 C 氧化酶(COX)活性在盐度为 8 时显著升高(P＜0.05), 并且鳃丝 PDH 和 COX 活性均与耗氧率呈显著线性正相关(P＜0.05)。盐度在 8 时罗氏沼虾的游泳足肌肉和腹部肌肉 HK、PFK 和 LDH 活性并无显著变化(P＞0.05), 但游泳足肌肉和腹部肌肉 PDH 和 COX 活性显著下降(P＜0.05); 盐度升至 12 时游泳足肌肉和腹部肌肉 HK、PFK、LDH、PDH 和 COX 活性均显著下降(P＜0.05)。运动能力结果显示, 盐度升至 8 时游泳能力显著下降(P＜0.05), 盐度升至 12 时弹跳能力显著下降(P＜0.05)。游泳能力与游泳足肌肉 PDH 和 COX 活性呈显著线性正相关(P＜0.05); 弹跳能力与腹部肌肉 HK、PFK 和 LDH 活性呈显著线性正相关(P＜0.05)。研究表明, 罗氏沼虾通过增加氧气摄取用于鳃丝有氧代谢以应对盐度胁迫, 但这些生理调节导致肌肉能量代谢酶活性下降, 造成罗氏沼虾的游泳和弹跳能力减弱。     

饲料中添加外源酶对大菱鲆幼鱼生长和饲料利用率的影响

研究了饵料中添加植酸酶、非淀粉多糖酶及二者的组合酶对大菱鲆幼鱼生长、体成分以及饵料利用率的影响。在水温14．0～18．5℃将144尾初始平均体质量为（20．53±0．10） g的大菱鲆幼鱼随机分成4组,每组3个重复,每个重复放养12尾鱼,分别饲喂基础饵料（对照组）和在每千克基础饵料中添加200 mg植酸酶、100 mg非淀粉多糖酶、200 mg植酸酶＋100 mg非淀粉多糖酶的组合酶（试验组）。计42 d。试验结果表明,与对照组相比,添加外源酶显著提高了大菱鲆幼鱼的特定生长率（ P＜0．05）,且添加组合酶的特定生长率最高,较对照组提高了16．30％;但摄食率、饵料系数、蛋白质效率和成活率均无显著影响（P＞0．05）。饵料中添加外源酶对大菱鲆幼鱼的鱼体水分、粗脂肪、灰分和能量无显著影响（P＞0．05）;但鱼体粗蛋白含量均有增加（P＞0．05）,且添加非淀粉多糖酶鱼体粗蛋白含量最高（P＜0．05）。与对照组比较,添加非淀粉多糖酶和组合酶显著提高大菱鲆幼鱼的干物质、粗蛋白、磷和能量的表观消化率（P＜0．05）;添加植酸酶显著提高粗蛋白表观消化率（P＜0．05）,干物质、磷和能量表观消化率较对照组高,但差异不显著（P＞0．05）。饵料中添加外源酶显著提高大菱鲆幼鱼氮、磷贮积率,显著降低氮排放率（P＜0．05）;添加组合酶显著降低磷排放率（P＜0．05）;饵料中分别添加植酸酶和非淀粉多糖酶未显著降低磷排放率（P＞0．05）,但有下降趋势。     

饥饿及恢复投喂对鮸幼鱼生长、耗氧率和排氨率的影响

在水温（12±1）℃和盐度24．3±0．61条件下，研究了饥饿及恢复投喂对鱿幼鱼生长、耗氧率和排氨率的影响。实验设置饥饿5、10、15d及连续饥饿4个水平，并设正常投饵对照组，各组饥饿结束后马上恢复正常投饵，整个实验历时30d，在实验前、饥饿结束时和实验结束时分别测定鮸幼鱼全长、体重、耗氧率和排氨率。结果表明：鮸幼鱼在饥饿状况下存活时间23d。实验结束时，饥饿5d和10d处理组鮸幼鱼全长和体重明显高于投喂对照组（P〈0．05）。在饥饿期间，连续饥饿组鮸幼鱼的耗氧率先下降又上升；排氨率前期显著升高，5d后达峰值，然后逐步下降；鮸幼鱼的O：N比值先下降，10d后达谷值，然后不断升高，20d后迅速升高到30．347。饥饿结束时，各饥饿组与投喂对照组耗氧率和排氨率差异显著（P〈0．05）。实验结束时，鮸幼鱼耗氧率除饥饿5d和10d组差异不显著外，其它各组间差异显著P〈0．05）；排氨率除投喂对照组和饥饿15d组差异不显著外，各组间差异显著（P〈0．05）。饥饿结束时和实验结束时O：N比值差异显著。可见，饥饿后恢复投喂的鮸幼鱼具有补偿生长能力。     

体重和温度对三种常见淡水螺耗氧率的影响

为研究体重和温度对三种常见淡水螺耗氧率的影响，用磨口试剂瓶作代谢测试瓶，进行了耗氧量测定。结果表明，环棱螺的耗氧率与其体重之间呈负幂函数关系．萝卜螺的耗氧率与体重之间为负半对数关系；环棱螺的耗氧率与温度之间为正指数函数关系，萝卜螺的耗氧率与温度之间为正幂函数关系；这两种淡水螺类的耗氧率在20．4～25．4℃范围内变幅较小，而在25．4～30．4℃范围内变幅较大。不同大小的环棱螺对温度变化的敏感程度有差异，小个体对温度变化的敏感程度较大。通过二元线性回归分析可知，温度、体重对耗氧率变化的影响程度也不尽相同。体重对耗氧率的影响程度明显大于温度对耗氧率的影响（P〈0．001）。     

鳜鱼、青鱼、草鱼、鲤、鲫、鲢消化酶活性的研究

鳜鱼、青鱼、草鱼、鲤、鲫、鲢肝脏蛋白酶活性低于肠蛋白酶。肠蛋白酶活性，鳜鱼最高，其余依次为青鱼、鲤、鲢、草鱼、鲫。鳜鱼、鲢的肠蛋白酶活性由前肠向后肠递减；而青鱼、鲤、草鱼的则由前肠向后肠递增；鲫则中肠活性最低。六种鱼不同组织的脂肪酶活性因鱼而异。青鱼、鳜鱼、鲤、鲢肝脏中脂肪酶活性低于肠脂肪酶活性（Ｐ＜０．０１）；而草鱼和鲫肝脏中脂肪酶活性与肠脂肪酶活性差异不明显（Ｐ＞０．０５）。六种鱼肝脏中脂肪酶活性由高到低依次为鳜鱼＞鲢＞鲫＞草鱼＞青鱼＞鲤；肠脂肪酶活性顺序为鳜鱼＞鲢＞青鱼＞鲤＞草鱼＞鲫。脂肪酶活性与鱼类食性无明显相关性。不同组织间淀粉酶活性存在差异。鳜鱼的肝脏和肠均有较高淀粉酶活性，青鱼和鲫肝脏中淀粉酶活性低于肠中的；草鱼、鲤和鲢肝脏中淀粉酶活性高于肠中的，但差异不显著。六种鱼中鳜鱼的肝脏淀粉酶活性明显高于其它五种无胃鱼，它们的淀粉酶活性顺序依次为鳜鱼＞鲢＞鲤＞草鱼＞青鱼＞鲫；肠淀粉酶活性顺序为鳜鱼＞鲫＞鲤＞青鱼＞鲢＞草鱼。     

主养草鱼池塘3种混养模式鱼类生长和效益比较

为进一步提高池塘养鱼的产品质量和经济效益,改善养殖生态环境,在武汉新洲973项目实验基地的9个陆基鱼池中,对主养草鱼的3种不同混养模式鱼类生长和效益进行了比较研究.模式Ⅰ放养草鱼、鲢、鳙和高背鲫,模式Ⅱ放养草鱼、鲢、鳙、匙吻鲟和高背鲫,模式Ⅲ放养草鱼、鲢、匙吻鲟和高背鲫.通过122 d的养殖试验,模式Ⅱ草鱼的生长不仅显著高于模式Ⅰ和模式Ⅲ(P＜0.05);经济效益对比分析发现,模式Ⅱ同样高于模式Ⅰ和模式Ⅲ.     

<Emphasis Type="Italic">Streptococcus agalactiae</Emphasis> from tilapia (<Emphasis Type="Italic">Oreochromis</Emphasis> sp.) transmitted to a new host,bighead carp (<Emphasis Type="Italic">Aristichthys nobilis</Emphasis>), in China

Several outbreaks of Streptococcus agalactiae infection of bighead carp (Aristichthys nobilis) were observed in China. The molecular epidemiology and pathogenicity of S. agalactiae in bighead carp and tilapia (Oreochromis sp.) is poorly understood. In the present study, we identified S. agalactiae strains isolated from diseased bighead carp using the API 20 Strep kit and 16S rDNA sequencing and determined whether these strains came from tilapia. Of the 46 identified S. agalactiae strains, 24 strains were successfully isolated from diseased bighead carps, 20 S. agalactiae strains were isolated from tilapia, and two S. agalactiae strains were isolated from tiger frog (Hoplobatrachus chinensis). The results of molecular typing, including multilocus sequence typing, molecular serotyping, surface protein gene detection, and virulence-related gene detection showed that the 44 strains from bighead carp and tilapia were highly similar, whereas different from tiger frog GBS strains. Remarkably, the bighead carp strain Hn1404 showed high virulence in bighead carp and zebrafish. Moreover, this strain was pathogenic to Nile tilapia (Oreochromis niloticus). In addition, comparative genomic analysis showed that isolate Hn1404 had a close relationship with the bighead carp and tilapia S. agalactiae strains. All the analyses of the genetic characteristics of bighead carp and tilapia strains showed that tilapia S. agalactiae strains could be transmitted to other fish species such as bighead carp.     

天鹅洲通江型长江故道“四大家鱼”种群遗传结构研究

利用淀粉胶电泳技术，对天鹅洲通江型故道青鱼（Ｍｙｌｏｐｈａｒｙｎｇｏｄｏｎｐｉｃｅｕｓ）（６０尾），草鱼（Ｃｔｅｎｏｐｈａｒｙｎｇｏｄｏｎｉｄｅｌｕｓ）（４０尾），鲢（Ｈｙｐｏｔｈａｌｍｉｃｈｔｈｙｓｍｏｌｉｔｒｅｉｘ）（４０尾），鳙（Ａｒｉｓｔｉｃｈｔｈｙｓｎｏｂｉｌｉｓ）（４０尾）的心、眼、脑、白肌、肝五种组织中ＬＤＨ、ＭＤＨ、Ｇ６ＰＤＨ及ＥＳＴ四种同工酶进行分析，并对这几种酶的一系列基因座位作了比较和定位，以此分别计算青、草、鲢、鳙的种群遗传变异率，为构建通江型长江故道“四大家鱼”种质资源生态库提供重要依据。     

高产成鱼池蓝绿色裸甲藻水华的研究

由蓝绿色裸甲藻(Gymnodinium,sp．)形成的蓝绿色水华是无锡渔区高产鱼池典型水质之一。本文对该藻的形态特征、生态、池塘培育和控制以及对鱼类的影响进行了研究。蓝绿裸甲藻水华具喜温、喜光、喜有机氮肥,喜红褐色水色(生物因子),且对外界环境的变化十分敏感等生态特点。蓝绿裸甲藻水华池的理化条件较差,特别是藻体繁殖过度,极易恶化水质,造成鱼类泛池。采用增施有机氮肥、合理使用增氧机、加水等综合措施可促进和控制该藻的繁殖。经鱼类消化道镜检表明,蓝绿裸甲藻能被鲢、鳙鱼及鲤、鲫、罗非鱼鱼种大量摄食,并被鱼类消化。对无锡河埒渔业一队成鱼池三年统计,蓝绿裸甲藻水华池的鲢鳙鱼净产量比无水华池高33．4～37．5％。     

五种鱼的鳞被复盖过程及其同生长的关系

用茜素红染色法观察研究了904尾鲤鱼、429尾草鱼、637尾鲢鱼、70尾鳙鱼及243尾尼罗罗非鱼的仔幼鱼。五种鱼鳞片出现时全长分别为：16—19，17—19，27—32，26—31，10-14mm。完成鳞被复盖时的全长分别为24—30，24—28，47—55，48—58，19—22mm。五种鱼鳞片出现均始于侧线，但出现部位和复盖过程可分为两类：鲤、草鱼、鲢及鳙的鳞片首先出现于躯干前部，为由前向后发展型，至于具体扩展过程，鲤与草鱼相似，鲢与鳙相同；罗非鱼的鳞片首先出现于尾柄，为由后向前发展型。鳞片出现、复盖过程同全长及年龄的关系的比较观察和回归分析表明，这一过程的始末及速度主要同体长增长有关，同年龄关系不大。鳞被发育过程不仅反映了不同鱼类的不同生长规律，亦可能有助于认识鱼类间的亲缘关系。     

Assessment of impact of the introduction of exotic fish species in north-east Thailand

Abstract. Within the framework of a fisheries project in north-east Thailand, project MK/FSPC/069 entitled ‘The Fish Seed Production Centre, North East Thailand’, an assessment was carried out of the ecological impact of introducing exotic fish species (common carp, Cyprinus carpio L., Nile tilapia, Oreochromis niloticus (L.), and Chinese and Indian carps). For the assessment, the protocol of Kohler & Stanley (1984) was followed, covering feasibility of introduction, acclimatization potential, potential impact, and control potentials. Regarding the (ongoing) use of the proposed exotic species in aquaculture, it was concluded that so far no clear ecological impact has been reported from escapes to open water; the use of the exotic species has shown to be highly beneficial from a 9 socio-economic point of view. Regarding the proposed introduction of the exotic species into public waters (natural lakes and man-made reservoirs), it was concluded that earlier releases of these species in north-east Thailand did not provoke severe ecological impact in terms of deterioration of aquatic ecosystems. Incidental cases of minor ecological impact were reported for common carp and nile tilapia. Indications were obtained for niche competition between Chinese and Indian carps and indigenous carps, while similar niche competition was concluded for bighead carp, Aristichthys nobilis (Richardson), and indigenous pelagic zooplankton feeders. Observing the prolific development of the Nile tilapia in a number of reported cases, it was recommended not to include this species in stocking programmes for public water bodies, until more risk assessments are available.     

不同混养鱼类和投喂方式对鱼蚌综合养殖水体化学特征的影响

选用草鱼(Ctenoparyngodon idellus)、银鲫(Carassius gibelio)、鲢(Hypopthalmichthys molitrix)、鳙(Aristichthysnobilis)作为本研究的混养鱼类,通过围隔实验检验了不同混养鱼类组合(草鱼+鲫+鲢+鳙或鲢+鳙)和配合饲料投喂方式(投喂或不投喂)对三角帆蚌(Hyriopsis cumingii)养殖水体化学特征的影响,实验为期155 d。结果表明,实验设计的混养鱼类组合可显著影响鱼蚌综合养殖水体的Ca2+、总碱度(Alk)、总硬度(HT)和总磷(TP)水平;投喂配合饲料可显著影响Ca2+、Alk、HT、氨氮(TAN)、TP和化学耗氧量(CODMn)。采用混养组合(草鱼+鲫+鲢+鳙)且投喂配合饲料的围隔内溶氧(DO)水平和透明度(SD)较低,Ca2+、HT、TN、TP、TAN和CODMn水平较高;采用混养组合(鲢+鳙)且不投喂的围隔内DO和SD水平较高,而Ca2+、HT、TN、TP、TAN和CODMn水平较低。随养殖时间延长,各组围隔内Ca2+水平下降,TN、TP、TAN和CODMn水平升高。实验期间,DO与SD水平呈正相关;DO和SD与TAN、TN、TP、Ca2+和CODMn水平呈负相关。因此,鱼蚌综合养殖中,控制CODMn和TAN浓度,维持Ca2+稳定及较高的DO水平是水质管理的基本目标。     

Growth of Triploid and Diploid Bighead Carp,Hypophthalmichthys nobilis

Growth of second-year triploid and diploid bighead carp, Hypophthalmichthys nobilis, was compared in a 189- to 190-day yield trial; the fish were grown separately in 0.04-ha earthen ponds at 625/ha and were also grown communally in 0.05-ha earthen ponds at 640ha. When grown communally, bighead carp were polycultured with channel catfish, Ictalurus punctatus (7,50Oha), and grass carp, Cienopharyngodon idella (40/ha); when they were grown separately, they were polycultured with grass carp at 501ha. When cultured separately, diploids were longer (526 vs 499 mm) and heavier (1,645 vs 1,427 g) than the triploids at harvest, but the differences were not significant (P 5 0.05). When cultured communally, the diploids were significantly longer (519 vs 485 mm) and heavier (1,621 vs 1,321 g) than their triploid counterparts at harvest. Ploidy of all bighead carp was determined after fish were harvested, and 7.9% of the presumed triploids that were stocked separately were actually diploids. Growth of the triploids appeared to be acceptable for commercial use where diploid bighead carp are banned. The efficiency of producing triploid bighead carp must be improved if they are to be cultured in states where bighead carp are illegal.     

三角帆蚌钩介幼虫在5种寄主鱼体寄生效果的比较

选用黄颡鱼、草鱼、鲢、鳙和鲫作为三角帆蚌(Hyriopsis cumingii)的寄主鱼,分析了寄苗悬液钩介幼虫密度和寄苗时间对5种鱼初始寄苗量的影响,并对寄生在这5种鱼上的钩介幼虫发育情况进行了观察。结果表明:无论高密度寄苗还是低密度寄苗,长时间寄苗还是短时间寄苗,黄颡鱼和草鱼的寄苗量都明显高于鲢、鳙和鲫。提高寄苗悬液钩介幼虫密度,寄主鱼的寄苗量显著增加,但增加寄苗时间,寄主鱼的寄苗量未见显著提高。黄颡鱼和草鱼的稚蚌脱苗率显著高于鲢、鳙和鲫,寄生在鲢、鳙和鲫鳃上的钩介幼虫约80%未发育至稚蚌便提前脱落。不论在寄苗量方面,还是在稚蚌脱苗率方面,黄颡鱼和草鱼均是三角帆蚌钩介幼虫的最佳寄主。     

Polyculture of silver barb, Puntius gonionotus (Bleeker), Nile tilapia, Oreochromis niloticus (L.), and common carp, Cyprinus carpio L., in Vietnamese ricefields: fish production parameters

The fish production parameters of five polyculture combinations, consisting of small and large silver barb, Puntius gonionotus (Bleeker), small and large Nile tilapia, Oreochromis niloticus (L.), and small common carp, Cyprinus carpio L., fingerlings in three replicates, were investigated in a rice-fish culture experiment (duration 149 days) conducted in the Mekong Delta, Vietnam. The survival rate was not significantly (P > 0.05) affected by the polyculture combination, but when grouped according to species, the mean survival of silver barb and tilapia was 64.3% and 63.7%, respectively, significantly higher than the mean common carp survival rate (33.4%). The growth of silver barb and tilapia was proportionally related to the stocking density, probably because of intraspecific competition and a synergistic interaction between silver barb and tilapia. The growth of common carp was not significantly different among the polyculture combinations. The highest net production (474.1 kg ha^?1) was obtained in the polyculture combination consisting of 80% small-sized silver barb fingerlings, but the fish was not marketable at that time. In concurrent rice-fish culture, it is recommended to raise large silver barb fingerlings. Small tilapia can be polycul-tured with silver barb, provided a stocking density lower than 1400 ha^?1. Common carp is considered less suitable because of a limited tolerance for the water quality conditions in the ricefield and the large size required by the market.