基于灰色系统理论的网箱养殖大黄鱼Pseudosciaena crocea (Richardson)疾病预报

为预报网箱养殖大黄鱼细菌性疾病的发生,以舟山市网箱养殖大黄鱼为研究对象,根据2001—2008年间舟山市网箱养殖大黄鱼发病情况的监测数据和各采样点海洋环境因子的测定数据,应用灰色系统理论探索了网箱养殖大黄鱼细菌性疾病的发生发展规律及其与环境因子的关系;建立了灰色预报模型GM(1,1)和GM(1,N),预报网箱养殖大黄鱼细菌性疾病的发生时间和发病率。灰色关联分析结果表明,大黄鱼细菌性疾病的发病率与养殖水域的环境因子都有不同程度的关联;把水温、悬浮物、无机氮和COD选作先行指标,用这些因子的不同组合建立了GM(1,5)、GM(1,4)和GM(1,3)模型,比较这些模型的平均相对误差,由无机氮和COD构成的GM(1,3)模型平均相对误差最小,为5.304%;用GM(1,1)模型对大规模细菌性疾病发生的时间进行了预测,预测结果与实际情况基本一致。     

网箱养殖大黄鱼溃疡病的预报模型

本文以舟山市网箱养殖大黄鱼Pseudosciaena crocea (Richardson)为研究对象,根据对2001-2005年间网箱养殖大黄鱼发病情况的观察分析、养殖水域环境因子的监测及其收集的气象资料,对大黄鱼溃疡病的发生规律和养殖环境的状况进行了全面分析,结果表明大黄鱼溃疡病的发生不仅与季节有关,而且还与环境因子的状况密切相关。在此基础上,进一步研究了环境因子对大黄鱼溃疡病发生的影响程度和影响方式,筛选出与大黄鱼溃疡病发生密切相关的环境因子,从而建立了网箱养殖大黄鱼溃疡病发生的预报模型。经检验该模型对预报大黄鱼的溃疡病是否发生及发生的程度有高度显著的效果,用该模型对舟山市2005年大黄鱼溃疡病的发生情况进行了预报,预报的正确率达到81.2%。为能有效、适时地对发病季节大黄鱼疾病的控制,本文还同时给出了网箱养殖大黄鱼发病季节溃疡病的预报模型。     

灰色拓扑模型在海州湾人工鱼礁区水质预测的应用

该研究分别采用残差修正的GM(1,1)模型和灰色拓扑预测方法对2007—2017年春(5月)、秋(10月)海州湾人工鱼礁区的溶解氧(DO)、化学需氧量(COD)、生化需氧量(BOD5)及溶解无机氮(DIN)4个指标的监测数据建立水质预测模型并选择精度较高的模型预测2018—2022年的水质变化趋势,最终利用2018年的调查数据对预测结果进行检验。结果表明,灰色拓扑模型相较于残差修正的GM(1,1)模型针对水质数据具有更好的预测精度,预测结果与2018年的调查结果较吻合,可信度较高;预测结果显示,DO和COD在2018—2022年能够保持良好的水质状态,可见人工鱼礁建设对海域水环境状况具有一定的修复作用,但BOD5和DIN存在一定的超标风险;针对灰色拓扑模型的改进仍具有很大的研究空间,有待进一步挖掘。     

海带对大黄鱼网箱养殖区水质的生物修复

为构建大黄鱼生态养殖模式,通过开展海带-大黄鱼间养试验,研究了该养殖模式下海带对大黄鱼网箱养殖区富营养化海水的生物修复效果。通过对生物修复区、非生物修复区和非养殖区的连续定时和定点监测,结果表明间养海带对大黄鱼网箱养殖区的富营养化海水具有明显的修复作用。经过28 d的连续监测,生物修复区的溶解氧(DO)浓度明显高于非修复区,无机氮(IN)、无机磷(IP)浓度均低于非修复区,同时生物修复区的化学耗氧量(COD)达到非养殖区的水平。因此,海带-大黄鱼的生态间养模式能有效降低富营养化水体中的IN和IP,并显著提高DO浓度,改善水质,这将为大黄鱼的健康生态养殖提供参考。     

象山港内新增网箱养殖污染物对海水水质的影响预测

象山港是宁波市最重要的网箱养殖港湾,网箱养殖带来丰厚经济利益的同时,也产生了大量的养殖污染物。文章以象山港内某新增大黄鱼网箱养殖基地为例,利用Deflt3D二维对流扩散模型预测养殖废水中的污染物对海水水质的影响。结果表明,新增大黄鱼网箱养殖产生的三种污染物浓度增量均是在网箱养殖点较高,在网箱养殖区外污染物随潮流运动迅速扩散,浓度增量降低,由于本项目规模小、时间短,其产生的养殖污染物对象山港水质的影响不大。但是,由于象山港内活性磷酸盐和无机氮已超标,对新增网箱养殖仍要严格评估其污染物排放浓度,以切实保护象山港海域环境,促进该海域养殖业的可持续发展,本文研究结果可为新增网箱养殖污染物预测提供参考。     

网箱饲养的大黄鱼病害防治

福建省闽东地区开展大黄鱼网箱养殖有10年了 ,至今全省大黄鱼养殖网箱已发展到2 0余万只 ,成为浅海养殖的龙头产业。近年来 ,由于网箱集中连片 ,布局不合理 ,海区水域环境有机质负荷急剧增大 ,呈现富营养化趋势 ,造成网箱饲养的大黄鱼大面积发病 ,且鱼病种类多、发病率高、危害大 ,对这一新兴的养殖业健康稳定发展起着严重的阻碍作用。因此 ,加强对大黄鱼病害防治技术的研究已刻不容缓。现就其主要病虫害的防治技术阐述如下。一、细菌性疾病1.弧菌病病原　　弧菌症状　　体表溃疡为其典型特征 ,随环境条件、感染途径的不同而有差别 ,并常有…     

深水网箱养殖病害综合防治技术

深水网箱养殖因集约化程度高、养殖密度大、单位水体产量高、产品质量高和经济效益显著等特点而备受瞩目。然而随着养殖生产的发展，深水网箱养殖的鱼类也出现了病害。根据2003年浙江省水产病害测报信息，部分地区深水网箱养殖的大黄鱼已不同程度地发生了细菌性疾病和寄生虫病，虽然对养殖生产造成的影响和损失并不大，但已经为深水网箱养殖的病害防治敲响了警钟。     

海水网箱养殖大黄鱼烂尾病的防治

据调查，舟山地区网箱养殖大黄鱼主要病害是烂尾病(即细菌性体表溃疡病)，本文对大黄鱼烂尾病的发病原因进行分析，并提出防治对策。     

不同养殖模式对大黄鱼肉质的影响

对工厂化养殖模式、网箱养殖模式养殖的大黄鱼和野生大黄鱼进行了肌肉常规营养成分、氨基酸和脂肪酸的分析比较。研究结果表明,工厂化养殖模式和网箱养殖模式的大黄鱼粗蛋白含量均显著低于野生大黄鱼(P0.05),粗脂肪含量均显著高于野生大黄鱼(P0.05)。工厂化养殖模式的大黄鱼必需氨基酸总量、呈味氨基酸总量和氨基酸总量均显著高于网箱养殖大黄鱼,但显著低于野生大黄鱼(P0.05)。工厂化养殖模式的大黄鱼多不饱和脂肪酸以及二十碳五烯酸+二十二碳六烯酸均显著高于网箱养殖的而显著低于野生大黄鱼(P0.05)。工厂化养殖模式养殖大黄鱼可以生产出肉质营养结构和风味优于传统网箱养殖的大黄鱼。     

铜合金围栏养殖大黄鱼海域水质综合评价与分析

为了评价铜合金围栏养殖大黄鱼(Larimichthys crocea)海域的水质状况,通过大黄鱼养殖期与非养殖期的4次调查,分析评价了调查海域海水中的p H、溶解氧、铜、锌、无机氮、活性磷酸盐等指标的区域分布、季节变化及污染水平,并利用内梅罗指数对调查海域水体进行了质量综合评价。结果表明:调查海域大黄鱼非养殖时间段的海水综合质量整体上属于清洁或者较清洁状态,大黄鱼养殖时间段的海水综合质量下降,分布趋势是以养殖网箱为高值中心,向外缘逐渐下降。     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

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.     

Growth hormone (GH) and reproduction: a review

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.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

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.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

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).     

Nitrogenous waste excretion and accumulation of urea and ammonia inChalcalburnus tarichi (Cyprinidae), endemic to the extremely alkaline Lake Van (Eastern Turkey)

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.     

Imported ornamental fish are colonized with antibiotic‐resistant bacteria

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.     

Effect of iodophor disinfection of non‐hardened Salmo trutta eggs on their bacterial and fungus load

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.     

Influence of the antibacterial herbs, Solanum trilobatum, Andrographis paniculata and Psoralea corylifolia on the survival, growth and bacterial load of Penaeus monodon post larvae

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.