卷口鱼的临界水温和溶氧量

本文测定了卷口鱼的临界水温和溶氧量，卷口鱼可生存的水温范围约是7-36℃，开始致死的临界上、下限温度分别为37℃和6℃，鱼浮头和窒息时的水溶氧量分别为1.72-2.04mg/L。和0.64-0.78mg/L。并对有关问题进行了初步探讨。     

倒刺鱼巴的临界水温和临界溶氧量的测定

本文测定了倒刺钯鱼种的临界水温和溶氧量。倒刺可生存的水温范围约是4℃-37℃，开始致死的临界上、下限水温分别为3℃-38℃；鱼开始浮头和窒息时的水溶氧量分别为1．84mg／1和0．96mg／1。并对有关问题进行了初步的比较探讨。     

倒刺鲃的临界水温和临界溶氧量的测定

本文测定了倒刺鲃鱼种的临界水温和溶氧量.倒刺可生存的水温范围约是4℃～37℃,开始致死的临界上、下限水温分别为3℃和38℃;鱼开始浮头和窒息时的水溶氧量分别为1.84mg/l和0.96mg/l.并对有关问题进行了初步的比较探讨.     

三种鲟科鱼类临界水温试验

本文主要研究了史氏鲟、俄罗期鲟及小体鲟三种鲟科鱼类的生存曙范围和摄食水温范围,试验表明,史氏鲟的生存水温范围０℃～３３℃,摄食水温范围４℃～３１℃,俄罗斯鲟的生存水温０℃～３３℃,摄食水温范围３℃～３℃;小体鲟的生存水温０℃～３２℃,摄食水温范围３℃～３１℃。     

野生卷口鱼的人工驯养初步试验

卷口鱼 (Ｐｔｙｃｈｉｄｉｏｊｏｒｄａｎｉ)俗名嘉鱼、老鼠鱼 ,其肉质细嫩 ,味鲜美甘香 ,经济价值高 ,古今驰名 ,是珠江水系特有的四大名贵河鲜之一 ,近年来有些渔农尝试将野生卷口鱼引入池塘或网箱养殖 ,但成活率往往很低。本课题组近两年来开展了野生卷口鱼的人工驯养工作 ,初步掌握了卷口鱼驯养的主要技术关键 ,明显地提高了养殖成活率 ,现扼要总结如下。1　鱼苗挑选卷口鱼为底层穴居性鱼类 ,栖息于江河底层的岩石洞隙之中 ,不易捕捉。渔民通常采用刺网捕捞 ,鱼被网卡住时间过长或极力的挣扎都易造成体表甚至内脏器官的受伤 ,往往内脏即…     

野生卷口鱼的人工驯养初步试验

本文扼要总结了野生卷口鱼的驯养技术，包括鱼种的挑选和暂养、鱼塘的生态环境和水质的调控以及饲料投喂等主要技术措施。     

珠江卷口鱼年龄生长、食性和繁殖的研究

本文报道了珠江卷口鱼的年龄生长、食住和繁殖方面的研究结果。通过分析确定:卷口鱼的年龄级由I—IV龄鱼组成,各龄鱼分别占渔获物总量的42.21％、38.21％、19.21％和0.38％。用统计学方法,计算出卷口鱼体长与鳞长的相关式为:L=8 43.30R(r=0.9956);体长与体重的相关式为:W=8.226×10~(-3)L~(3.374)(Γ=0.9654)。对卷口鱼各种食物的组成、季节变化及出现率作了分析探讨。卷口鱼个体绝对怀卵量波动于7878—48880粒之间,平均22250.7粒。绝对怀卵量与体长和体重的相关式为:R=4.5419L~(3.6208)和R=40.88W 1209. 文中对卷口鱼的资源繁殖保护,网具使用和合理捕捞规格等问题进行了讨论。     

卷口鱼耗氧规律的研究

卷口鱼的耗氧量随着体重的增长而增加，Y=0.3539X^0.5646。耗氧率却随着体重的增长而减少，Y=0.3519X^-0.4340。水温和水流量对耗氧率都有影响。在一定水温范围内，耗氧率随着水温的上升而增加，Y=0.0038X^1.2711；在一定的流量范围内，耗氧率随着流量的增大而增加，Y=0.0012X^-0.5086。鱼的呼吸耗氧率存在较明显的昼夜变化。白天的耗氧率均值大于晚上。     

梭鱼的临界温度和临界氧量

本文报道了梭鱼的临界温度和临界氧量。临界温度进行了低温和高温致死试验，临界氧量进行了浮头时和窒息时的溶氧量测定。     

珠江卷口鱼形态特征与染色体组型

对珠江卷口鱼形态特征和染色体组型进行了初步研究。在珠江干流西江的肇庆、郁南、桂平以及其上游柳江的柳州采集野生卷口鱼450余尾,全长165～236 mm,体重167.84～586.25 g。随机选取试验鱼进行观察、解剖、测量和拍照。发现卷口鱼具有形态多样性。在体型上,一种体高较高,为高背型,主要来自桂平极其下游;另一种为平背型,主要来自柳州及上游。在体色上,腹部颜色变异较大。腹部颜色有乳白色、黄色和棕黑色三种。无雌雄异型现象。卷口鱼口下位,内卷;咽齿较发达,鳞中等大,侧线鳞式37～46,5～8/5～6-A。胃不发达,肠长为体长的1.36～1.51倍。肋骨14,脊椎骨38-40。以肾脏为材料,用空气干燥法制备染色体标本,卷口鱼的染色体数目为2n=50,核型公式为12 m 16 sm 18 st 4 t,NF=78。     

西江流域卷口鱼线粒体D-loop序列的遗传多样性分析

为研究西江流域广西境内卷口鱼(Ptychidio jordani)种群的遗传变异情况,自广西境内6个江段采集了139尾样本,采用PCR与DNA测序技术分析其线粒体D-loop序列的遗传多样性及群体历史动态;139条D-loop序列长度均为725 bp,碱基组成A+T (65.7%)远远高于C+G (34.3%),共检测到变异位点25个,转颠换比R值为11.5。139尾样本共定义23个单倍型。单倍型的NJ系统树以及网络结构图显示,23个单倍型间有2个明显分支,不同地理群体来源的单倍型混杂分布在2个分支中,未能观察到明显的地理聚群。6个群体遗传多样性较好,单倍型多样性Hd=0.71585~0.92063,核苷酸多样性Pi=0.00173~0.00668,遗传分化极其显著(遗传分化系数Fst=0.36737,P<0.001)。AMOVA分析表明,群体内变异占63.26%,群体间为36.74%。中性检验(Tajima’s D= –0.50322,P=0.34600;Fu’s Fs= –5.05210,P=0.08800)与核苷酸错配分布表明,西江流域卷口鱼种群近期内未经历过种群扩张。综上所述,西江流域广西境内的卷口鱼遗传多样性表现为高单倍型、低核苷酸多样性的特征,群体间不同程度的遗传分化表明水坝阻隔及捕捞因素可能促进其发生,而水利梯级开发可能是促进卷口鱼群体遗传分化的首要原因。     

Modeling and implementing the use of aeration to increase water temperature and dissolved oxygen in greenhouse aquaculture cages

In this study, an unique bamboo floating cage was built in order to heat the water used for rearing Nile tilapia (Oreochromis mossambicus x O. niloticus) and climbing perch (Anabas testudineus, Bloch) in Northern Thailand during the colder rainy and winter seasons. This special greenhouse fish cage (SGFC) was covered with polyethylene to heat the surface air with solar energy, and insulated to prevent heat loss. The water temperature at depths of 0.1, 0.3 and 0.8 m was modeled and measured. In various trials, the cages were aerated with and without heated air from the surface. It was found that the thermal efficiency of the SGFC integrated with hot air aeration at a water depth of 0.80 m was 32.65 %. Throughout the day, the average water temperature was 31.82 ± 0.68 °C, which was 0.76 °C higher than the water temperature outside the experiment, and the amount of oxygen in the water of 11.35 ± 0.13 mg/l. The SGFC can produce one extra fish harvest per year when compared with regular fish cages. Development equations to describe the thermal model were used for predicting the water temperature in the SGFC and thus validating the model. Moreover, the economic analysis of the SGFC found that the payback period was one year, seven months and fourteen days.     

紊动对水体过饱和溶氧释放的影响初探

为探究紊动对水体中溶氧释放的促进效果,设计以潜水泵排水的方式,开展了不同水泵数量、功率、摆放方式、排水方向等工况下过饱和溶氧释放过程研究试验。结果表明,紊动对水体中溶氧释放有较好的促进效果。放入5个泵(功率20 W、纵向排水)时,水体溶氧释放系数为0.514 h~(-1),是未放入水泵时溶氧释放系数0.026 h~(-1)的19.77倍。当水泵垂直于水面排水时,溶氧释放效果较好。水泵个数越多、功率越大,溶氧释放系数越大,溶氧释放效果越好。     

水温、盐度和溶氧对红鳍东方鲀幼鱼游泳能力的影响

为了考查水温、盐度和溶氧对红鳍东方鲀(Takifugu rubripes)幼鱼游泳能力的影响,测定了其在不同水温[15.2、20.2、25.6(对照)和30.4℃]、盐度[0、10、20、32(对照)和40]和溶氧[2.14、4.10、5.81和7.36 mg/L(对照)]条件下的临界游速和最大游速。结果表明,水温和溶氧含量均显著影响实验鱼的临界游速和最大游速(P0.01)。随水温和溶氧含量升高,实验鱼的临界游速和最大游速均逐渐增加。水温(T,℃)与临界游速(U_(crit),cm/s)和最大游速(U_(max),cm/s)均呈二次函数关系,关系式分别为U_(crit)=-0.095T 2+5.450T-47.79,R~2=0.995(P0.01)和U_(max)=-0.018T 2+2.204 T-12.27,R~2=0.981(P0.01)。溶氧含量(DO,mg/L)与临界游速和最大游速也均呈二次函数关系,关系式分别为U_(crit)=0.230DO2+1.561DO+5.84,R~2=0.995(P0.01)和U_(max)=-0.806 DO2+11.10DO-3.919,R~2=0.985(P0.01)。不同盐度下实验鱼的临界游速和最大游速与对照组均无显著差异(P0.05)。结论认为,低温和缺氧会降低红鳍东方鲀放流苗种的游泳能力,进而降低其放流后的捕食成功率,提高被捕食概率。     

静态注射化学发光法测定水样中的溶解氧

基于Luminol—I2化学发光体系,建立了一种静态注射化学发光法测量水中溶解氧的测定方法。该方法灵敏度高．试剂用量少。线性范围（DO）为0．20～15．00mg&#183;L^-1对浓度为0．20mg&#183;L^-1的DO平行测定10次,相对标准偏差2．76％？样品回收率介于95％～105％之间。试验表明,该方法适合水体中溶解氧的测定.     

方斑东风螺的耗氧率及饲养水中溶氧变化的初步研究

为对方斑东风螺养殖生产提供参考依据,试验测定了饥饿和饱食状态下方斑东风螺幼螺在不同水温(25℃、28℃、30℃)时的耗氧率,测定了幼螺摄食后水中溶解氧浓度的变化。结果表明,饱食后幼螺的生理代谢活动加强,耗氧率增加;随着水温的升高,耗氧率也增加。幼螺摄食后水中的溶解氧浓度随着时间的延长不断下降。试验观察发现,在方斑东风螺养殖的正常水温范围内(25℃~30℃),DO高于3mg/L时,幼螺生活正常;DO在2.40mg/L~2.35mg/L时,幼螺表现为缺氧状态;DO在1.5~1.0mg/L时,幼螺表现为严重缺氧状态。     

A respirometer system to measure critical and recovery oxygen tensions of fish under simulated diurnal fluctuations in dissolved oxygen

We describe a computer-operated recirculating respirometer system (ca. 140 L water) with six respirometer chambers and a reference chamber (L × W × H: 26 cm × 12 cm × 20 cm; volume 6.24 L) that simulates diurnal dissolved oxygen (DO) fluctuations normally occur in aquaculture ponds. A gas-mixing device, “Digamat” proportionately dissolves gaseous nitrogen and oxygen (and if desired, carbon dioxide) in water to achieve DO levels from 1.0 to 40.0 kPa (0.3–14.0 mg L^?1) at different temperatures. A series of computer-operated valves sequentially allow water from respirometer chambers to a single oxygen probe to measure DO concentration. Oxygen consumptions of fish as the differences in DO concentrations between respirometer and reference chamber are used to calculate different metabolic rates (standard, routine, and active), and critical (P _c) and recovery (P _r) oxygen tensions of individually reared unfed and fed fish. An experiment was conducted to evaluate the ability of the system to measure metabolic parameters for individually reared Nile tilapia (Oreochromis niloticus L.) at three temperatures (low: 22.5, optimum: 27.5 and high: 33.5 °C). The fed fish had significantly higher P _c and P _r values at optimum and high temperatures than unfed fish. At low and high temperatures, both fed and unfed fish had higher P _c and P _r than at optimum temperature. The standard metabolic rate was significantly higher at higher temperatures (44.9, 51.7, and 77.7 mg O₂ kg^?0.8 h^?1 at 22.5, 27.5, and 33.5 °C, respectively).