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1.
近年来,随着我国社会经济的快速发展,生态环境问题日益突出,这给我国的水产养殖业带来了十分不利的影响。再加之传统水产养殖业的基础设施比较落后,并且养殖病害也在不断增加,严重制约了水产养殖也的发展。因此,我们应积极探索水产生态养殖模式,推动水产养殖业的可持续发展。本文分析了目前我国水产养殖业存在的问题,并就水产生态养殖与新养殖模式的发展战略进行探究,仅供大家参考。  相似文献   

2.
浅析渔药滥用原因与药物残留的危害(上)   总被引:2,自引:0,他引:2  
一、水产养殖中滥用药物的原因1.养殖环境恶劣,规范用药困难随着水产养殖业竞争的加剧,水产养殖集约化程度的不断提升,养殖种类的逐渐增多,养殖密度也不断加大,工农业对养殖水域的污染以及养殖业自身产生的污染日益严重,导致养殖水环境急剧恶化。在恶劣的养殖水环  相似文献   

3.
近年来,随着科技的不断发展,水产养殖业也得到良好的发展。为了水产养殖业健康稳定的发展,需要先进的水产养殖技术的支持。因而,对水产养殖技术推广存在的问题进行分析,并提出了相应的解决对策。  相似文献   

4.
随着水产养殖业的发展,养殖对象的多样化,养殖规模日益扩大,集约化程度也不断提高。然而养殖区水质不断恶化,养殖生态系统严重失衡,导致细菌性、病毒性等病害的感染机率随之增大,使水产养殖业的健康发展受到影响。  相似文献   

5.
鱼病防治与科学用药(上)   总被引:1,自引:0,他引:1  
《科学养鱼》2004,26(4):76-76
随着水产养殖业的不断发展,养殖规模不断扩大,养殖密度大幅度提高,苗种和亲鱼在地区之间的流动更加频繁,使所养殖的水产动物病害的传播也日趋严重。水产动物病害已成为威胁水产养殖业的一个严重问题。尤其是大量抗生素的应用,超量和长期使用同一种杀虫剂使病原体的抗药性不断增  相似文献   

6.
我国设施水产养殖业的发展现状与趋势   总被引:2,自引:0,他引:2  
我国是世界水产养殖大国,2011年养殖水产品产量已达4023.26万吨,占当年全国水产品总产量的71%,占世界养殖水产品总产量的70%左右.水产养殖业的快速发展与设施水产养殖业的发展和带动作用是分不开的.设施水产养殖业是现代水产养殖业发展的一个主要方向和重要途径,具有节地、节水、节能、高产、高效和可控的优势,代表着一个国家渔业科技水平,是现代水产养殖业发展的必然趋势.设施水产养殖业的本质是渔业工业化生产.  相似文献   

7.
渔业在越南国民经济中发挥着重要作用,其中水产养殖业占国内渔业产量的40%,越南拥有广阔的适宜发展水产养殖的水域和土地,近年来水产养殖业取得了快速增长。越南积极开展多品种养殖。也是亚洲少数几个进行有机水产养殖并出口到欧洲的国家。政府希望通过不断的努力,克服不利因素,保持国内水产养殖业的发展势头。  相似文献   

8.
近几年来,唐山市水产养殖业发展迅速,养殖病害也非常严重,一度制约了水产养殖业的健康发展.为解决病害问题,唐山市水产技术推广部门围绕水产养殖防疫问题做了大量工作,现把有关情况归纳如下:  相似文献   

9.
改革开放以来,在水产科技不断突破的有力支撑下,我国水产养殖业实现了快速增长,产量不断攀升,2011年水产品养殖产量达到4023.26万吨,占水产品总产量的71.80%,产业结构持续优化,发展方式逐渐开始由"量"向"质"转变,水产业在保障国家粮食安全和改善人民生活方面发挥着越来越重要的作用.伴随着水产养殖业快速发展,水产品市场和贸易持续扩大,水产品市场成为国内农副产品市场蓬勃发展的主要推动力之一.与此同时,近年来水产养殖成本持续增加,水产品价格总体持续增长,特别是高档水产品价格上涨过快,水产养殖市场风险不断推高,逐渐成为制约产业发展的重要因素.因此,深入分析水产品市场规律,合理规避市场风险,成为当前促进水产养殖业健康发展的重要命题.  相似文献   

10.
随着我国水产养殖业的快速发展,集约化程度也在不断提高,水产养殖系统中的残饵、动物代谢物、动植物尸体的沉积,以及水源的外来污染加剧等,使得养殖水体中的病原体大量繁殖,导致养殖水体的环境和生态环境严重恶化,造成水产养殖病害频发,经济损失日渐严重.  相似文献   

11.
12.
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   

13.
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   

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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