共查询到20条相似文献，搜索用时 671 毫秒
1.
鱼蚌混养对池塘水质、藻相结构及三角帆蚌生长的影响 总被引：2，自引：1，他引：1
2012年4月26日—2012年12月12日通过在鲢鳙鱼养殖池塘中放养不同密度的三角帆蚌,研究不同三角帆蚌放养比例对鲢鳙鱼养殖池塘中水质、藻相结构及三角帆蚌生长的影响。实验中,鲢鳙放养比例统一为3∶7,总密度为1.5尾/m3。三角帆蚌放养密度则设置4个水平,分别为单养鲢鳙鱼池塘(0只/m3),低密度三角帆蚌混养池塘(0.8只/m3),中密度三角帆蚌混养池塘(1.0只/m3)和高密度三角帆蚌混养池塘(1.2只/m3)。结果显示,混养三角帆蚌池塘的水化指标(TP、PO4-P、NH3-N、NO2-N和NO3-N)均显著低于单养鱼池塘。中密度三角帆蚌混养池塘除NH3-N和化学需氧量(COD)与低密度三角帆蚌混养池塘无显著差异外,其他各项水化指标均显著低于其他3个池塘,并且极显著低于单养鲢鳙鱼池塘。单养鲢鳙鱼池塘藻类平均密度均极显著高于鱼蚌混养池塘,其中在鱼蚌混养池塘中浮游植物密度与三角帆蚌密度成负相关关系。单养鲢鳙鱼池塘的浮游植物生物量均极显著低于中、高密度鱼蚌混养池塘,并且显著低于低密度混养池塘。浮游植物生物量与三角帆蚌密度成正相关关系,鱼蚌池塘中绿藻和裸藻的生物量在养殖过程中上升显著。低、中密度三角帆蚌混养池塘三角帆蚌存活率均显著高于高密度三角帆蚌混养池塘;低密度混养池塘中蚌湿重、壳长及壳宽相对增长率均为最大,显著高于中、高密度三角帆蚌混养池塘。研究表明,养鱼池塘混养三角帆蚌不仅能改善养殖池塘的水质,还能控制藻类数量,促使绿藻和裸藻等大型藻类的生长,提高养殖水体浮游植物的生物量总量,最终还能有效提高三角帆蚌的存活率及生长率。从改善水质,藻相结构,蚌成活率及生长等指标角度考虑,在鲢鳙鱼养殖池塘中,三角帆蚌最佳放养密度为1.0只/m3。 相似文献
2.
鲢、鳙对三角帆蚌池塘藻类影响的围隔实验 总被引：6，自引：3，他引：3
以浙江金华汤溪威旺养殖基地的三角帆蚌养殖水体为研究对象,通过围隔实验比较研究了单养鲢、鳙和三角帆蚌的池塘浮游植物密度、生物量和优势种(属)组成等的差异,以及养蚌池混养鲢鳙对水体浮游植物密度、生物量以及优势种变化的影响。结果表明,养蚌(10#)围隔的浮游植物平均密度和生物量均显著高于高密度鲢(12#)围隔(P<0.05),其蓝藻数量及生物量显著高于高密度鲢(12#)和低密度鳙(13#)围隔(P<0.05),绿藻数量则显著低于低密度鲢单养(11#)围隔(P<0.05)。在鱼蚌混养的情况下,单养蚌(10#)围隔浮游植物平均数量显著高于鲢-蚌混养(15#,16#)和鳙-蚌混养(17#,18#)围隔(P<0.05),其蓝藻数量及生物量极显著高于鲢-蚌混养(15#,16#)或鳙-蚌(17#,18#)围隔(P<0.01),其绿藻数量显著低于混养高密度鲢(16#)或低密度鳙(17#)的混养围隔(P<0.05)。研究结果充分说明,鲢、鳙和三角帆蚌三者对水体藻类组成的影响有别,三角帆蚌养殖池中适当混养鲢或鳙可以有效控制蓝藻(铜绿微囊藻)的生长,促进绿藻(四尾栅藻)的生长,并最终有利于三角帆蚌的养殖,混养鲢密度的增加有利于控制藻类生长,而鳙密度的增加促进了裸藻等中大型藻类的生长。 相似文献
3.
南湾水库鲢鳙放养比例对水质调控的研究 总被引：2，自引：0，他引：2
本研究跟踪调查了鲢、鳙鱼种的放养比例由20∶80调整为40∶60,鲢鱼的放养量由4.373g/m3增加到8.747g/m3,鳙放养量由17.494g/m3减少到13.120g/m3,对南湾水库水质理化指标与浮游生物的影响。研究结果表明调整鲢、鳙鱼种的放养比例后,南湾水库的水质得到了一定的改善,表现为COD、BOD和叶绿素a含量显著降低,透明度显著升高,富营养化状态出现减轻的趋势。另外,从浮游生物调查的结果来看,增大鲢放养比例,能显著降低浮游植物的数量和生物量,同时也大大降低了蓝藻在藻类群落中所占的比例及其生物量,有效地避免了水库蓝藻水华的爆发。 相似文献
4.
不同规格和投苗密度对仿刺参池塘网箱保苗效果的影响 总被引：2，自引：0，他引：2
仿刺参室外池塘网箱保苗是近年来兴起的一种半生态式的保苗方式。于2014年7—11月在仿刺参室外池塘网箱保苗期间,通过现场试验比较研究了不同投苗规格[大规格(0.093±0.004)g/头,小规格(0.024±0.001)g/头]和密度(低密度125g/m3、中密度250g/m3、高密度375g/m3)两因素对仿刺参苗生长、成活率和产量的影响。结果表明,对于同一规格的仿刺参苗,低密度组体质量与特定生长率高于中、高密度组;相同密度条件下,大规格苗种成活率显著高于小规格(P0.05),小规格低密度组仿刺参苗的成活率显著高于高密度组(P0.05),大规格低密度组仿刺参苗的成活率显著高于中、高密度组(P0.05)。不同密度组收获仿刺参苗的总产量无显著差异(P0.05),但低密度组收获仿刺参苗的净产量高于中、高密度组。通过两因素方差分析可知,规格的主效应及二者的交互作用对仿刺参苗成活率有显著的影响(P0.05),密度的主效应对仿刺参苗成活率有极显著的影响(P0.001);两因素的主效应及其交互作用对仿刺参苗总产量均无显著的影响(P0.05)。规格主效应及二者的交互作用对仿刺参苗净产量的影响不显著(P0.05),密度主效应对仿刺参苗净产量有显著的影响(P0.05)。因此,仿刺参室外网箱保苗过程中投放大规格、低密度苗种能够保证较高的成活率和净产量,而且可以节省苗种资源和饵料投喂量,降低单位面积生产成本和管理成本,提高产出投入比和经济效益。 相似文献
5.
为了研究流水养殖系统中养殖密度对井冈山地区西伯利亚杂交鲟（西伯利亚鲟Acipenser baerii♀×施氏鲟Acipenser schrenckii♂）幼鱼生长性能的影响,本文以初始体重为7.89±0.45 g/尾西伯利亚杂交鲟幼鱼为研究对象,设置了低密度组（1.16 kg/m3）、中密度组（1.74 kg/m3）和高密度组（2.32 kg/m3）三个密度组进行为期90 d的养殖生产实验,通过比较分析不同密度组西伯利亚杂交鲟生长指标、体成分含量、抗氧化酶活性和相关基因表达水平发现,低密度组幼鱼终体重、增重率及特定生长率显著高于中密度组和高密度组（P＜0.05）,各密度组实验鱼的存活率无显著性差异;水分和灰分随着养殖密度的增加而增加,且存在显著性差异,粗脂肪和粗蛋白未出现明显的差异;肝脏超氧化物歧化酶（SOD）和谷胱甘肽硫转移酶（GSH-ST）的酶活力在实验末期低、中密度组显著高于高密度组（P＜0.05）,随着养殖密度的增加,幼鱼肝脏丙二醛（MDA）含量不断增加,过氧化氢酶(CAT)活力降低,MDA和CAT在实验期间未出现明显的差异;结果还发现,高密度组与生长相关的生长激素受体（GHR）、胰岛素样生长因子-1（IGF-1）、胰岛素样生长因子-2（IGF-2）基因表达水平显著降低（P＜0.05）;高密度组与应激相关的热休克蛋白70（HSP70）基因表达水平在45d出现差异（P＜0.05）,90 d后高密度组显著高于低密度组（P＜0.05）,低密度组热休克蛋白90（HSP90）基因表达水平在30d时显著低于中、高密度组（P＜0.05）,实验末期,3个密度组间均存在显著的差异（P＜0.05）。
研究结果表明,实验条件下,中、低密度条件下西伯利亚杂交鲟幼鱼表现出良好的生长性能,因此建议,井冈山地区西伯利亚杂交鲟幼鱼养殖密度控制在1.16 kg/m3-1.74 kg/m3之间。 相似文献
6.
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
7.
双壳贝类是淡水生态系统常见的滤食性动物,以浮游植物和有机物悬浮颗粒为食,其作用可能降低蓝藻浓度,从而促进沉水植物生长。通过构建4组（草＋蓝藻、草＋蓝藻＋低生物量蚌、草＋蓝藻＋高生物量蚌、草）室外微型生态系统,研究了湖泊下风区常见蓝藻堆积浓度下,三角帆蚌（Hyriopsis cumingii）的滤食作用对蓝藻水华和沉水植物苦草（Vallisneria natans）生长的影响。结果表明：（1）蓝藻对苦草的生长具有显著抑制作用,草藻组和草组的相对生长率分别为-7.65mg/g·d和7.19mg/g·d;（2） 相似文献
8.
《水产科学》2015,(12)
试验池塘4口,每口面积0.8hm2,水深1.8m,放养体质量50g的草鱼12000尾,体质量24~100g的鲢鱼500尾,体质量150g的鳙鱼100尾,常规管理,其中2口池塘放养1龄河蚌两万只,2口对照塘不放河蚌,定期采集水样,测定水中浮游植物种类和数(生物)量。结果表明,鱼蚌混养塘中有浮游植物6门48属94种,而对照塘中仅有6门42属91种。混养塘与对照塘水体中均以绿藻门的种类为主,分别占总数的47.8%和41.8%。鱼蚌混养组中以绿藻为优势种群,出现频率较高的优势藻类为:硅藻门的小环藻、针杆藻,绿藻门的小球藻、栅藻、新月藻;而对照组中的优势种不仅有试验组中的优势种类,还包含了蓝藻门的平裂藻、螺旋藻、微囊藻以及硅藻门的直链藻、舟形藻、双壁藻,绿藻门的梭形藻等。鱼蚌混养组与对照组中浮游植物多样性指数分别为1.24~1.41和1.26~1.36,鱼蚌混养组中浮游植物多样性指数均略高于对照组。鱼蚌混养组浮游植物密度为539.23×104个/L~1289.53×104个/L,生物量为6.68~12.47mg/L;对照组浮游植物密度为669.57~1608.50×104个/L,生物量为8.40~18.62mg/L,鱼蚌混养组浮游植物的密度和生物量略低于对照塘,且差异显著(P0.05)。结果表明,鱼蚌混养模式可有效控制塘中浮游植物的繁殖与生长,浮游植物的多样性指数提高,池塘生态系统更加稳定。 相似文献
9.
为了解养殖密度对鹦鹉鱼生长及生理生化指标的影响,设置三个养殖密度梯度组进行实验:低密度组(5.04 kg/m^3)、中密度组(10.12 kg/m^3)、高密度组(15.35 kg/m^3),每组设3个平行,实验鱼投喂56 d后测定其生长及生理生化指标。结果表明,中密度组鹦鹉鱼末体重显著高于高密度组(P<0.05),与低密度组无显著差异(P>0.05);低密度组鹦鹉鱼增重率显著高于中密度和高密度组(P<0.05);低密度组鹦鹉鱼血清和肝脏中SOD、GSH-PX、GPT和GOT显著高于其他组(P<0.05);中密度组鹦鹉鱼血清和肝脏中的MDA显著高于高密度组(P<0.05),与低密度组无显著差异(P>0.05)。由此表明,当养殖密度达到较高密度(15.35±0.25)kg/m^3时,会显著影响鹦鹉鱼的健康,产生较为严重的负面影响。 相似文献
10.
三角帆蚌对蓝藻的滤食作用及其对沉水植物生长的影响 总被引：2，自引：0，他引：2
双壳贝类是淡水生态系统常见的滤食性动物,以浮游植物和有机物悬浮颗粒为食,其作用可能降低蓝藻浓度,从而促进沉水植物生长。通过构建4组(草+蓝藻、草+蓝藻+低生物量蚌、草+蓝藻+高生物量蚌、草)室外微型生态系统,研究了湖泊下风区常见蓝藻堆积浓度下,三角帆蚌(Hyriopsis cumingii)的滤食作用对蓝藻水华和沉水植物苦草(Vallisneria natans)生长的影响。结果表明:(1)蓝藻对苦草的生长具有显著抑制作用,草藻组和草组的相对生长率分别为-7.65mg/g·d和7.19mg/g·d;(2)三角帆蚌对蓝藻具有明显的下行滤食压力,其大小与蚌生物量有关,蚌生物量高时效果明显;(3)三角帆蚌的滤食可以不同程度上缓解蓝藻对苦草的生长抑制,低蚌组和高蚌组苦草相对生长率分别为-5.31mg/g·d和4.24mg/g·d。蓝藻颗粒被滤食后,水体光照条件的改善可能是有蚌组苦草生物量相对较高的主要原因。说明双壳贝类可以通过滤食浮游植物使水体理化环境向着有利于沉水植物生长的方向发展,但这种作用的大小与贝类生物量的合理配置有密切关系。 相似文献
11.
Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean 
下载免费PDF全文
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
12.
13.
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
14.
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
15.
16.
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
17.
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
18.
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
19.
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
20.