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1.
海洋捕捞业是辽宁渔业的主体。全省拥有捕捞渔船2.7万艘、总马力70万匹,从事捕捞渔业劳动力10万人。 纵观辽宁省海洋捕捞业的发展历史,综合分析目前所面临的形势,问题是很严峻的:一是机动渔船发展失控、近海资源破坏严重。80年代以后,辽宁省机动渔船与马力增加,不但捕捞产量不是同步增长,而且马力单产呈下降趋势。这就说明捕捞强度大大超过了渔业资源的再生能力。再从1994年渔船数量分析看,小型渔船比例大:22马力以下的渔船占总船数的80％;40～120马力占18％;135马力以上占2％,其中200马力以上仅占0.9％。这就表明,辽宁省两万余艘小型渔船拥挤在沿岸、近海渔场竞相捕捞,不但加大了对近海渔业资源的破坏力度,而且造成渔场秩序混乱。二是渔船在外海捕捞能力在弱化。  相似文献   

2.
导管螺旋桨在木质渔船上的应用   总被引：1，自引：0，他引：1  
夏泰淳  章可畏 《海洋渔业》1990,12(4):164-165
<正> 70年代中期以来,中国沿海机动渔船迅速增加,其中250马力以下的小型渔船占极大比例。虽然渔船大量增加,但海洋捕捞产量不尽人意,海洋鱼类资源状况在不断地恶化。为此,我们认为,在国家大力发展远洋和外海渔业的同时,必须尽快减经近海捕捞压力,加强渔政管理,同时对数量众多的中小型渔船实施技术改造,鼓励和吸引他们向外发展。  相似文献   

3.
山东省烟台地区，几年来，水产品产量一直稳定在37万吨以上，其中海洋捕捞产量占总产量的70％左右，主要是由几千只机动渔船投入生产。渔船性能和技术状况，直接关系到捕捞产量和经济效益的高低。十多年来，我区重点抓了钢质渔船的试验和推广工作，截止1982年年底，全区拥有120马力以上钢质渔船365只、91000余马力，占120马力以上机动渔船总只数的41％、总马力的53％(详见表1)，钢船年捕捞产量已达到12万吨，经济效益普遍好于木船，成为我区海洋捕捞生产的主力军．  相似文献   

4.
众所周知,由于捕捞强度不断增加,我国近海渔业资源严重忍化,主要经济鱼类资源不断减少。十年俞,全国海洋捕捞机动渔船有3.9万艘,270万马力。但十午来,‘这种‘局面并没有好转,渔船总马力扔以每年20万、30万、50万的速度逐年增加。1987年国务院办公厅颁发了《关于近海捕捞机动船控制指标的意见》,但据19B7年底统计,全国海洋捕捞机动渔韶已达19万艘币20多万马力,目前已突破20不艘,730万马力,超少控制指标4万多艘。80多万马力,比1978年渔船数圣增加了4悟,马力也增加了1.7倍。 造成我国海洋捕捞机动渔船发展失控的原因,除了劳动力自然增长、捕…  相似文献   

5.
按照国家农业部加快发展远洋渔业和省委省政府外向牵动战略,辽宁省沿海水产战线以捕捞渔船改造为突破口,加大渔船马力,改进渔船性能,增强外海远洋捕捞作业能力,打破了海洋捕捞徘徊前进的局面,去年全年捕捞产量可达到85万吨,比上年增加10万吨,增长13.3％。是近10年来增长最快的时期。  相似文献   

6.
渔船是海洋捕捞的主要工具,是海洋渔业生产力发展水平的重要标志.实施渔船更新改造工程,对于促进海洋捕捞转型升级、增加渔民收入、维护渔区和谐稳定起着十分重要的作用. 一、南通市海洋捕捞渔船的基本情况 南通是江苏的海洋捕捞大市,海洋捕捞产量一直占据江苏的50％以上.历史最高峰全市拥有海洋捕捞机动渔船7583艘、功率30.1万千瓦、捕捞产量38万多吨.为保护和合理利用渔业资源,促进海洋渔业的可持续发展,近年来,南通认真贯彻农业部出台的海洋捕捞渔船船网工具控制制度(渔船数量控制和渔船功率指标控制,简称"双控"),积极组织渔船报废拆解和渔民转产转业(简称"双转")工作.2002年开展渔船报废拆解工作以来,全市共拆解报废渔船1110艘,弃捕转产从事海水养殖29艘,实施部、省、市海洋捕捞渔民转产转业配套项目40多个,8000多渔民弃船转产从事海水养殖业或其它产业.另外,该市渔民还自行报废拆解了一批旧、小渔船.  相似文献   

7.
到一九七七年止全省有机帆渔船7769艘，54．6万马力。机帆船产量在全省海洋捕捞量中所占的比．重自1971年起已占70％以上。近几年由于捕捞过度，沿海资源有波动，机帆渔船单产有所降低，但总产量仍达1338．9万担的水平。随着作业渔场逐渐向外推移，机帆渔船总的趋势是向大型化方向发展。  相似文献   

8.
目前，海康海洋渔业深海机拖渔船单船功率．已从六十年代的80马力发展到730马力，单机最大功率达到412马力；刺钓作业渔船从六十年代的20马力发展到300马力．最大单机功率达到150马力。海洋捕捞作业渔船多数是使用国产柴油机，少量深海机拖渔船在近年来使用重庆引进美国“康明斯”NTA-855-M机型，和河南洛阳引进西德(MWM)曼海姆TBD234V8机型，  相似文献   

9.
广东去年各项渔业生产建设都有新的进展。在海洋捕捞方面,全年更新改造了渔船3500多艘,其中仅新增加的中深海大中型拖网、大围网、刺钓渔船便达470多艘,近9万匹马力。通过渔船的更新和技术改造,使前往中深海、外海作业的渔船生产能  相似文献   

10.
荣成市现有海洋捕捞渔船3100余艘、27.7万马力，其中135马力以上744艘，从业劳力2．5万人。捕捞业是全市渔业的支柱和龙头。它不仅提供了全市60％的水产品产量和63．3％的水产品产值，而且还带动了水产食品加工、渔船渔机修造、网具绳索和包装物料生产等相关产业的发展，对保持  相似文献   

11.
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.
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.
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.
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   

15.
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   

16.
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   

17.
There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future.  相似文献   

18.
This study investigated the efficiency of iodophor disinfection (135 ppm active iodine for 15–30 min) of non‐hardened Salmo trutta eggs against different groups of bacteria and against fungus. Egg samples were taken from non‐disinfected and from disinfected eggs, microorganisms were cultured on specific nutrient media and their mass was measured by turbidimetric methods. Bacteria and fungus mass of non‐hardened eggs could be reduced but not eliminated by iodophor disinfection with 135 ppm active iodine for 15 min. The extent of reduction was 47–65% (Experiment 1). The efficiency of disinfection increased with disinfection time as the reduction in bacteria and fungus mass was 40–55% after 15 min and 58–74% after 30 min (Experiment 2). Disinfection efficiency of iodophor solution diluted in water (reduction 49–57%) and of iodophor solution diluted in sodium chloride solution iso‐osmolar to the oocytes (reduction 52–61%) was similar (Experiment 3). The reduction in bacteria and fungus mass was persistent as it was 39–72% lower in embryos deriving from disinfected eggs than in embryos deriving from non‐disinfected ones (Experiment 4). In conclusion, the tested disinfection method is inadequate to eliminate pathogens completely but it could positively influence immune defence of eggs and embryos.  相似文献   

19.
The indiscriminate use of antibiotics and chemicals in shrimp hatcheries has led to biomagnification and that in turn could lead to rejection of a whole consignment. The application of the bioencapsulation technique as a tool for curative treatment in shrimp larvae was investigated. Herbs having antibacterial properties such as Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia (methanolic extracts) were bioencapsulated in Artemia and fed to Penaeus monodon post larvae PL 1–25. The post larvae were reared in a medium inoculated with pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi and Vibrio sp. Post larvae reared in the non-inoculated water and fed with non-enriched Artemia exhibited 90% survival, highest specific growth rate (12.43%) and reduced bacterial load. P. monodon reared in the bacterial inoculated water and fed with the non-enriched Artemia exhibited the lowest survival (10–30%), specific growth rate (8.42–9.1%) and increased bacterial load (2.86 × 103 to 3.76 × 105 cfu/g). The methanolic extracts of the herbs helped to increase survival and specific growth rate and reduced bacterial load in the P. monodon culture system. Among the three herbal extracts, P. corylifolia enriched Artemia fed post larvae showed the tendency to higher survival (>50%), growth rate (11.5 averaged) and low bacterial load (1.12 × 105 cfu/g). This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

20.
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   

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