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莱州湾虾池养殖罗非鱼的静水围隔生态系浮游植物的初步研究↑（*） 总被引：4，自引：1，他引：4
本文报道了在１９９４年７月至９月间莱州湾海水养罗非鱼围隔生态系浮游植物优势种、叶绿素浓度与理化因子的关系。各浮游植物优势种与理化因子的相关性基本一致，但其相关程度不同，主要优势种卵形隐藻、海洋原甲藻和扁藻与各理化因子的关系最紧密。从总体水平上，各种理化因子对浮游植物影响的相对重要性依次为ＴＮ＞ｐＨ＞ＴＰ＞ＮＯ２－Ｎ＞ＤＯ＞ＣＯＤ＞ＳＤ＞ＮＨ４－Ｎ＞ＰＯ４－Ｐ。氮磷对浮游植物的相对影响取决于氮、磷的比值。在本实验条件下，适宜的 ＴＮ／ＴＰ为 １８左右。施鸡粪和投饵两种养鱼方式中，氮和磷分别是浮游植物生长的限制因子。本文还就浮游植物变动对罗非鱼的影响进行了讨论。 相似文献
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不同单养及混养海水实验围隔水化学的研究 总被引：5，自引：1，他引：4
１９９５年６～１０月和１９９６年６～８月对不同单养和混养海水实验围隔的水化学研究结果表明：围隔中盐度、总氮、总磷和化学耗氧量（ＣＯＤ）在雨季前逐渐升高,进入雨季后降低;投饵养殖时围隔中磷浓度较低氮浓度较高,其中混养中国对虾和台湾红罗非鱼的围隔活性磷（ＰＯ４－Ｐ）浓度相对较高,混养对虾与菲律宾蛤仔的围隔氨氮（ＮＨ３－Ｎ）浓度较高,投铒兼酌情施肥养殖时围隔中氮浓度较低磷浓度较高,其中混养中国对虾与缢蛏 相似文献
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光合细菌在盐碱地池塘改良水质的研究 总被引：14，自引：1，他引：13
研究了光合细菌（ＰＳＢ）在低洼盐碱地池塘围隔中对水化因子和浮游生物的影响。结果表明：ＰＳＢ的施用对水化因子有较大的影响,其中水体中ＤＯ、ＮＯ３－－Ｎ升高,而ＮＨ４－Ｎ、ＮＯ２－－Ｎ、和ＣＯＤ降低,而对ＰＯ４３－－Ｐ影响不明显。当ＰＳＢ浓度高时,可提高水体的ｐＨ值;对浮游生物无明显影响;ＰＳＢ的一次施用量为１０ｐｐｍ,一次效用时间为６天左右,因而ＰＳＢ可达到改良水质,进而改善水质的目的,尤其在水质恶化时,其作用更显重要。 相似文献
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通过室内实验研究了中肋骨条藻和海洋原甲藻对中华哲水蚤繁殖的影响,并采用顶空固相微萃取-气相色谱质谱法对两种微藻内源醛类进行定性定量分析。结果表明,与海洋原甲藻相比,中肋骨条藻对中华哲水蚤的存活率、产卵率和孵化率都存在负面影响。在微藻内源醛类分析中,检测到中肋骨条藻中含有6种醛类,而在海洋原甲藻中仅检测到两种醛类。不论是从单种醛类的含量上,还是醛类总含量上,中肋骨条藻中醛类含量都明显高于海洋原甲藻,这意味着硅藻释放的醛类物质对中华哲水蚤的繁殖和存活具有潜在的抑制作用。 相似文献
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水产养殖池塘裸藻水华的特点、危害和调控 总被引：1，自引：0，他引：1
水华是水体藻类大量生长或聚集并达到一定浓度的现象,是水体富营养化和特定条件综合作用的结果。能够形成水华的藻类有蓝藻、甲藻、硅藻、隐藻、绿藻、裸藻等,其中,蓝藻、甲藻水华比较常见, 相似文献
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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％。 相似文献
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无锡市河埒口高产鱼池水质的研究——Ⅱ.浮游生物 总被引：9，自引：0，他引：9
无锡河埒口高产鱼池的浮游植物量多在20-100毫克／升之间，以隐藻门为代表的鞭毛藻类占很大优势，绿球藻类和硅藻类次之，蓝藻极少。浮游动物量平均大约为浮游植物量的114-1／3，以轮虫为主。当地养鱼池的水色，主要由膝口藻、隐藻、裸甲藻和绿球藻的水华颜色决定的。膝口藻水华是渔民最欢迎的“肥水”，隐藻水华和绿球藻类水华为一般“肥水”，裸甲藻水华被称为“转水”。文中对“肥、活、嫩、爽”的生物学内容同浮游生物量及鲢、鳙鱼产量的关系进行了分析。 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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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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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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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
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William King V David L. Berlinsky Craig V. Sullivan 《Fish physiology and biochemistry》1995,14(6):489-500
Plasma estradiol-17 (E2), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E2 and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E2 and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass. 相似文献