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残饵及代谢物对斑节对虾育苗的影响 总被引：1，自引：0，他引：1
试验对象为平均体重0.57毫克、全长6.5毫米的斑节对虾后期幼体,放养在充气的海水水族箱内,密度为每升20尾,试验用的饲料为碎虾肉,各试验组的投饲量分别为10毫克/升、50毫克/升、100毫克、250毫克/升和500毫克/升,并设一水族箱投喂硅藻作对照。试验结果表明:投饲量为10毫克/升、50毫克/升、100毫克/的试验组,后期幼体的增重率接近,且都比对照组高一倍左右;最低投饲量试验组的成活率较好,与对照组比较无显著差异(P>0.05);其它试验组的成活率随投饲量增加而下降;投饲量为50毫克/升时,仔虾的成活及生长均可,超出这个投饲量,水体中有机物和代谢物积累加快,溶氧量下降,水质迅速恶化。 相似文献
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苏州澄湖渔业资源调查及综合开发思路 总被引：4，自引：0，他引：4
2001年3月-12月。对澄湖的水质理化因子，水生生物等方面进行调查。结果为：pH值7.3-7.7，透明度0.3-0.8米，溶氧7.2-10.2毫克/升，COD13.3-17.3毫克/升，氨态氮0.5-1.3毫克/升，总磷0.090-0.156毫克/升，酚0.001-0.004毫克/升；浮游植物7门72属，生物量12.7331毫克/升；浮游动物63属91种，生物量3.27毫克/升；底栖动物（软体动物）73.6179克/米^2。澄湖属天然中-富营养型湖泊，适宜采取调整品种结构，保护和开发优质野生鱼类资源，走合理开发，可持续发展经营之路。 相似文献
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为了提高尼罗罗非鱼(以下简称尼罗鱼)商品规格和养殖尼罗鱼的经济效益,我们进行了一冬龄尼罗鱼与家鱼混养的试验,现将1983年试验结果报告如下:一、材料和方法1.试验池条件。试验池6口,总面积117.2亩,水深2～2.5米。7、8、9三个月分别对各池水的主要理化因子和浮游生物量进行测定,测得的平均值为:水温24～33.5℃,pH6.5～7.2,溶解氧1.4～14.7毫克/升,有机物耗氧量11.99～16.79毫克/升,浮游植物量473.7～2,331.4万个/升,浮游动物量15.3～35.1万个/升。2.试验鱼来源及放养情况。尼罗鱼种由本场越冬温室提供,规格为5～15克,先后于4月30日、5月 相似文献
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高关水库浮游生物现存量及鲢,鳙鱼产潜力的研究 总被引：4，自引：1，他引：4
根据1985年3—11月采样测定结果,高关水库浮游植物生物量平均密度为125.3万个/升,生物量为1.9208毫克/升;浮游动物平均密度为4012个/升,生物量为4.80毫克/升。根据浮游生物现存量估算鲢、鳙鱼产潜力为25万公斤,其中鲢5.8万公斤,鳙19.2万公斤。本文还对高关水库鲢、鳙的合理放养问题进行了探讨。 相似文献
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本品属双烷基二甲基卤类复合制剂 ,其特性在规定浓度范围内起到高效、速效杀灭野杂鱼、细菌、病毒、寄生虫卵及藻类而却能维持虾、蟹存活的作用。现简介如下 :1 清塘灭鱼作用 作者在 6口平均水面 2 0平方米、水深 1米的水泥池中放养草、鲢、鳙、鳊、鲤、鲫、罗非鱼、罗汉鱼、鱼、鱼参鱼、及虾虎鱼等品种 ,应用本剂分别使池水成 5、 6、 7、 8、10毫克 /升浓度及设对照池比较。这些池水水质ｐＨ7 5～ 8 2 ,硬度 3 8毫克 /升 ,溶解氧 >4毫克 /升 ,水温 2 0～ 2 2℃。经观察 4 8小时的结果表明 :鲢、鳙、鳊、罗非鱼、鱼参鱼、罗汉鱼及… 相似文献
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农药杀虫双对鱼类毒性的研究 总被引：1，自引：0，他引：1
由实验得出杀虫双对鲤鱼、白鲢96小时半致死浓度分别为4.7毫克/升、4.51毫克/升,而安全浓度则分别为0.47毫克/升,0.451毫克/升;对草鱼胚胎最大无作用浓度为1.0毫克/升,对大型水蚤96小时半致死浓度为0.13毫克/升。综合评价杀虫双的毒性,0.13毫克/升浓度对鱼类生长、鱼卵胚胎发育,以及饵料生物均无急性毒性作用,以此浓度乘0.1(应用系数)得0.013毫克/升,故建议渔业水体杀虫双浓度以不超过0.013毫克/升为宜。 相似文献
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太湖是我国第三大淡水湖泊,湖底平坦,平均水深2.27米,年平均水温17.28℃,降雨量1,000毫米以上,水质基本良好。湖区饵料生物丰富,浮游植物年平均生物量为4.85毫克/升,浮游动物为4.77毫克/升,底栖生物的现存量平均是4.8克/米~2,是鱼类生长的良好场所。 相似文献
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鱼儿离不开水,确切点说,主要是离不开水中的饵料和溶解氧。水中饵料的丰欠,关系着鱼类的生长,溶解氧含量的高低,则决定鱼儿的生存。据资料,鱼类正常生活的适宜溶解氧含量,在每升水含氧五毫克以上。溶解氧含量低于1毫克/升时,鱼就要因缺氧浮头,低于0.5毫克/升时,鱼就要窒息死亡。一般来说,在天然水体中,不会出现缺氧现象。但是,目前在池塘养鱼事业上,往往采取多品种、高密度的放养方式,加大投饵施 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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Iciar Martinez Amaya Velasco Ricardo Pérez-Martín Eskil Forås Michiaki Yamashita Carmen G. Sotelo 《Journal Of Aquatic Food Product Technology》2013,22(4):289-297
The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus. 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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Qin-Cheng Huang Di‐Gen Qin Bei‐Ping Tan Tao Du Yuan-Zhi Yang Qi-hui Yang Shu‐Yan Chi Xiao-hui Dong 《Aquaculture Research》2020,51(2):816-827
A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg. 相似文献