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高容量鱼池初级生产力和产氧、耗氧值特点的初步研究 总被引：1，自引：0，他引：1
本文总结了亩净产为1500～2600公斤的高容量(高载鱼晕)鱼池水域初级生产力和产氧、耗氧值的特点，在透明度为28～40厘米的条件下，“水呼吸”耗氧量占31．3％；池鱼呼吸（考虑到活动和摄食生长因素)占61．8％，与一般精养鱼池“水呼吸”耗氧要占约70％，池鱼占20％和其它因子的耗氧占10％的情况有着明显的区别；高容量鱼池在透明度为35～40厘米时，2米深水柱毛产氧量约等于水呼吸耗氧晕，而一般精养鱼池2米深水柱的毛产氧量要小于水呼吸耗氧量。由此证明，高容量鱼池所采取的排除底层污泥的池塘改造措施以及经常排除底层负氧水、及时添补新鲜水的水质控制技术，对于减少“水呼吸”耗氧量，改善池水溶氧条件是有效的。高容量鱼池由于载鱼量高，仅依靠水体的产氧，溶氧的收、支还不平衡，因此，使用增氧设备自然是重要的增产措施。 相似文献
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当今对虾养殖,由于细菌性,病毒性等病害外源性感染的机率较大,养殖户大都采用封闭式、半封闭式养殖管理模式,因此虾池的水质调控尤为重要。为了使对虾养殖能持续健康发展,生产上通常的几项化学指标是可以根据养虾的不同阶段而加以管理的。一、前期管理经过清淤、暴晒、消毒后的池塘,经过7－10天左右毒性消失后,进入稳定状态,可以认为此时的水质是最佳的。在该阶段的水质管理,主要是补充适量的有机或无机N．P．K肥,培养浮游植物和浮游动物。我们知道浮游植物光合作用产氧量占海水池塘溶氧收入可达91．3～100％,是池塘中氧的主要… 相似文献
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增氧设备在水产养殖中的应用 总被引：1，自引：0，他引：1
养殖水体中的溶氧水平关系到养殖水生动物的生存、生活和生长,进而关系到养殖成败和养殖效益的高低。根据对我国传统池塘养殖水体中溶氧水平的监测和数据分析,在水体总溶氧量中,70％左右的溶解氧来自于水体中的植物尤其是浮游植物的光合作用,30％左右来自于大气的溶入。通常情况下,水体上层的溶氧量较高,池塘底层水体的溶氧量较低,往往低于lmg／L。溶氧水平的高低直接影响着养殖鱼、虾的摄食量、饲料转化率以及生长速度。据有关资料显示,养殖鱼类在溶氧Nc3mg／L时的饲料系数要l：t4mg／L时增大1倍;在溶氧量7mg／L时, 相似文献
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北方地区冰封期时间比较长 ,特别是东北、西北等地区 ,冰封期最长的可达１５０天以上 ,冰下水温低（约为１～３℃） ,对鱼类的安全越冬影响很大。影响鱼类安全越冬的最主要外因就是越冬池塘的溶氧量。越冬池塘封冰后 ,水中溶氧在自然状况下 ,同时存在耗氧和产氧两个方面的因素。耗氧主要是由于水中的生物呼吸和有机物的氧化等原因造成的。而产氧主要是由于水生维管束植物（某些沉水植物）及浮游植物的光合作用的结果。生物增氧 ,简单地说 ,就是根据具体情况 ,创造一切有利条件 ,促进冰下浮游植物的生长、繁殖并在光合作用中产生氧气 ,作为越… 相似文献
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中国对虾与罗非鱼施肥混养的基础研究↑（*） 总被引：3，自引：0，他引：3
用４个海水池塘陆基围隔（５ｍ×５ｍ）,进行了封闭式施肥混养中国对虾（Ｐｅｎａｅｕｓｃｈｉｎｅｎｓｉｓ）与台湾红罗非鱼（Ｏｒｅｏｃｈｒｏｍｉｓｍｏｓａｍｂｉｃｕｓ×Ｏ．ｎｉｌｏｔｉｃｕｓ）的基础研究。结果表明,在不同密度条件下,对虾成活率４５．０％～８６．７％（平均６６４．２％）,产量为７５．７～１１１．８ｋｇ／ｈｍ２（５７ｄ）,生产力为０．１９／ｍ２·ｄ。池塘对中国对虾的负荷力为１７０．０ｋｇ／ｈｍ２。其中某些围隔对虾死亡较多的原因是负荷量超过了负荷力,发生饵料缺乏和自残。在限定罗非鱼放养量（８×１０３尾／ｈｍ２）的条件下,鱼虾最适放养尾数配比为１∶３,中国对虾（体长５．５５ｃｍ）的最适放养量为２４×１０３尾／ｈｍ２左右。 相似文献
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大口鲇鱼种耗氧率和窒息点的观测 总被引：11，自引：0，他引：11
对平均全长７．６ｃｍ和１１．６ｃｍ的大口鲇鱼种耗氧率和窒息点进行了测定。结果表明：小规模鲇种耗氧量比大规格低，但耗氧率比大规格高。２种规格鱼种的最高耗氧率分别出现在白天１０：００和１２：００左右。鱼种溶氧窒息点分别为０．３３ｍｌｇ／Ｌ和０．３６ｍｇ／Ｌ，与四大家鱼相似或销强，适合养殖和长途运输。 相似文献
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家鱼池塘底泥耗氧率与理化因子的相关性分析 总被引：1，自引：0，他引：1
采用原位底泥耗氧测定法,研究了10口家鱼鱼池底泥耗氧率与底部水体理化因子(溶氧、温度、pH值、氧化还原电位)和底泥有机质含量及深度的相关关系。结果显示:池塘平均底泥耗氧率(SOD)为0.91 g/(m2.d),变动范围为0.76～1.09 g/(m2.d)。双变量相关性分析表明,底泥耗氧率与池塘底部水体理化指标的相关性均达到极显著水平(P<0.01),与溶氧相关性最高(Pearson相关系数为0.779),其次是温度、pH值和氧化还原电位,相关系数分别为0.587、0.557和-0.421;底泥耗氧率与底泥深度相关性达到显著水平(P<0.05)。偏相关分析结果表明,底泥耗氧率与溶氧和温度呈极显著相关(P<0.01),与其它因素均未达到显著水平。影响底泥耗氧率最重要的环境因子是溶氧,其次是温度。利用BP神经网络分析影响SOD的理化因子,以溶氧、温度和底泥深度为BP神经网络模型的输入变量建立BP神经网络模型对SOD进行预测分析,BP神经网络模型训练和测试相关系数分别为0.911和0.879,平均相对误差分别为11.6%和10.4%,预测值与真实值偏差较小,拟合度较高,可有效预测池塘底泥耗氧率。 相似文献
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Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean 
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下载免费PDF全文 The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna. 相似文献
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Liping Li Rui Wang Wanwen Liang Xi Gan Ting Huang Yan Huang Jian Li Yunliang Shi Honglin Luo Ming Chen 《广西水产科技》2014,(1)
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China. 相似文献
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In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg. 相似文献
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Growth hormone (GH) and reproduction: a review 总被引：5，自引：0，他引：5
Florence Le Gac Odile Blaise Alex Fostier Pierre-Yves Le Bail Maurice Loir Brigitte Mourot Claudine Weil 《Fish physiology and biochemistry》1993,11(1-6):219-232
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations. 相似文献
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Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation. 相似文献
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Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection 下载免费PDF全文
下载免费PDF全文 G Sharon M Pimenta‐Leibowitz M C L Vilchis N Isakov D Zilberg 《Journal of fish diseases》2015,38(1):67-74
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality). 相似文献
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Sandra García‐Garrido Ismael Hachero‐Cruzado Carlos Rosas Pedro Domingues 《Aquaculture Research》2013,44(11):1741-1751
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting. 相似文献
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The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated. 相似文献
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There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future. 相似文献