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1.
1990年3月15日-4月9日在室内自然温度变化条件下(11-18℃),采用浓度1-5‰的康威营养盐溶液培养湛江叉鞭金藻。结果表明,3‰浓度对增殖效果最好,经6天培养,细胞密度由65.5-76.0×104ml-1。  相似文献   

2.
1试验条件1.1 设施、设备育苗池14个,有效面积 420 m2,规格 5m ×6 m×1.3 m;M级沙滤池 2个,规格 5 m×2m×1.5 m;海边沙滤井 1口;单胞藻培养池 16个,规格 3 m×5 m×0.8 m;12 m3/h罗茨鼓风机1台;蒸发量为2t/h的锅炉1台。1.2 试验材料 饵料为人工培育的等鞭金藻、牟氏角毛藻、青岛大扁藻、异胶藻及海洋酵母。亲蚶系采自浙江乐清人工养殖的3龄泥蚶,规格160粒/kg。2试验方法2.1催产、孵化用沙滤海水冲刷掉亲蚶外壳上的犯及沉垢,然后用500×10-6的高…  相似文献   

3.
《科学养鱼》2001,(10):56-56
1.购买虾苗时应检查有无白体病,有病虾苗不要买,同时虾苗入池前应消毒,用0.4×10-6浓度溴氯海因全池泼洒,3~5天后再用活性微生态制剂按1.5×10-6浓度全池泼洒,调节水质,抑制有害微生物生长繁殖。2.平时每月用一次溴氯海因0.4×10-6浓度全池泼洒,每月使用一次虾宁2%按饵料量或虾菌宁5‰按饵料量或虾康宁6‰按饵料量一次,连用3天。3.治疗方法:第一天用溴氯海因0.5×10-6浓度或二溴海因0.3×10-6~0.5×10-6浓度全池泼洒,第二至第六天内服虾宁4%+虾菌宁5‰…  相似文献   

4.
用济兴牌强力消毒剂进行室内和鱼塘防治细菌性鱼病试验。室温25℃,用0.4×10-6消毒剂24h即能全部杀灭赤皮、烂鳃、肠炎病原菌;轻病鱼塘用0.5×10-6,重病鱼塘用0.8×10-6消毒剂全池泼洒,2天1次,2~3次即愈。  相似文献   

5.
EDTA对紫彩血蛤幼虫发育的影响   总被引:7,自引:0,他引:7  
本文研究了EDTA对紫彩血蛤幼虫生长,存活和变态的影响。结果表明,所有试验的EDTA浓度均能促进幼虫生长,前期3.0×10^-6浓度组生长最快,幼虫平均壳长由对照组的235.6μm增至239.7μm,后期则以1.0×10^-6浓度且生长最快,幼虫平均壳长由对照组的247.4μm增至253.0μm;0.5×10^-6-5.0×10^-6EDTA均能提高幼虫的存活率和变态率,其中以1.0×10^-6效  相似文献   

6.
在鲍育苗生产中可以用孔雀石绿的草酸盐来替代敌百虫杀灭培育池中的桡足类。使用 1.0×10-6的孔雀石绿处理3小时与使用1.5~2.0×10-6的敌百虫处理15~20小时的效果基本一致,且对底栖硅藻和鲍无明显副作用  相似文献   

7.
虾池浮激植物初级生产力的研究   总被引:12,自引:2,他引:10       下载免费PDF全文
阎喜武  何志辉 《水产学报》1997,21(3):288-295
用黑白瓶测氧法对辽宁省庄河青堆水产公司虾池整个养殖期间(5-9月)浮游植物初级生产力进行研究。虾池浮游植物的初级生产力为(5.45±2.36)gO2/(m^2.d),日P/B系数为2.39(0.67-6.66),浮游植物对太阳有效辐射的利用率为0.78(0.24-2.18)%,浮游植物毛产量到虾产量的转化效率为7.41%;回归分析表明,浮游植物生物量和太阳有效辐射量是决定虾池浮游植物初级生产力大小  相似文献   

8.
我们自1996年开始,在虾池中进行了大面积养蟹技术研究,并获得了良好的效果,现报告如下:1材料与方法1.1池塘条件秦楼办事处万平口虾场5个池塘,面积分别为20亩、25亩、30亩,水深1~1.5 m,泥沙底质。水质良好,进、排水方便。1.2清池肥水池塘冬闲时,封池曝晒20~30天后清淤。1月下旬进水浸没滩面。使用“敌杀死”0.1~0. 2×10-6,清除以杂蟹类为主的甲壳类敌害生物。3月上旬,当池水温度达8~10℃时,使用20~25×10-6的茶籽饼清除害鱼。毒性消失后,注入用60目筛绢网过滤的海水…  相似文献   

9.
等鞭金藻对次氯酸钠中有效氯耐受力的研究   总被引:1,自引:0,他引:1  
采用不同质量分数的次氯酸钠 ,以不同的处理时间对等鞭金藻 30 11进行耐受力研究。结果表明 :在试验的取值范围内处理时间比有效氯质量分数对等鞭金藻的生长影响更显著。在实际应用中 ,次氯酸钠的质量分数 (有效氯 )以 4× 10 -6~ 8× 10 -6,处理时间约 2h为宜  相似文献   

10.
王金宝 《齐鲁渔业》2001,18(2):21-21
在草鱼养殖过程中,出血病是鱼种培育阶段一种广泛流行、危害性大的病毒性鱼病,发病率高,流行季节长,可造成大批草鱼鱼种的死亡,危害甚大。笔者根据多年实践经验,现将此病的防治方法介绍如下: (1)清除池底过多淤泥,并用200× 10-6生石灰或20×10-6漂白粉(含有效氯30%)或10×10-6漂白精(有效氯60%)消毒。 (2)鱼种下塘前,用聚乙烯氮戊环酮碘剂 60×10-6药浴25分钟左右,或用鱼复药3号 20~30×10-6药浴 30~60分钟。 (3)每万尾鱼种用水花生 4 kg,捣烂后拌入 250g…  相似文献   

11.
12.
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   

13.
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   

14.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
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   

15.
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   

16.
17.
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   

18.
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   

19.
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   

20.
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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