长江口中华绒螯蟹亲蟹培育技术探讨

通过在长江口地区进行中华绒螯蟹亲蟹培育,获得了97.4％的暂养成活率,暂养增长率在1.08％～1.34％之间;经过海水促产,获得抱卵亲蟹47 000只,平均抱卵率为90.4％,平均抱卵量为38.8万粒/只,抱卵亲蟹产前起捕率为76.6％.试验认为在长江口地区提高亲蟹抱卵率是可行的,同时本文就试验中发现的问题进行了分析和探讨     

河蟹亲蟹促产及抱卵蟹培育技术要点

河蟹人工育苗中亲蟹促产及抱卵蟹培育是关系到育苗成效的两个重要生产环节。作者通过多年来的生产性试验，亲蟹的抱卵率和抱卵蟹成活率均达９０％以上。促产处理宜在３月上中旬进行（水温在１０℃以上），促产地面积在１０００ｍ２上下，投放亲蟹密度为７５０ｋｇ／１０－１公顷，雌雄性比掌握在２～３：１，待绝大多数雌蟹抱卵后应及时将雄蟹捕出。抱卵蟹培育的关键是防逃、合理投饲及水质管理。     

提高抱卵亲蟹越冬成活率的几项技术措施

中华绒螫蟹(河蟹)春季早期育苗生产所用亲蟹，一般在上年的深秋或初冬交配抱卵。提高其抱卵率和越冬成活率，获得质优量足的抱卵亲蟹，足整个育苗生产顺利进行的基础，应把亲蟹的越冬培育作为首要管理工作抓早抓好。     

河蟹亲蟹的越冬饲养

河蟹(Eriocheir sinensis)亲蟹的越冬成活率及抱卵量是直接影响当年生产和成本的因素。我们于1994～1995年在赣榆县榆城育苗场进行河蟹人工育苗,将购进的1500公斤雌蟹(共12000只)经交配促产后,散养于3个室外土池(面积共3600多平方米)中越冬,采苗获得抱卵亲蟹11031只,越冬成活率为91:9％,每只抱卵亲蟹的平均采苗量为26万只,育苗取得成功。现将亲蟹越冬饲养技术总结如下。     

河蟹养殖技术之二提高抱卵亲蟹越冬成活率的技术措施

中华绒螯蟹(河蟹)春季早期育苗生产所用亲蟹一般在上一年的深秋或初冬交配抱卵,提高亲蟹抱卵率和越冬成活率是整个育苗生产顺利进行的基础,因此,应把亲蟹的越冬培育作为首要管理工作抓早抓好.     

锈斑(虫寻)亲蟹培育试验初报

从市场采购或由野外采捕野生锈斑(虫寻)的成体,采用内分泌、营养和环境条件三个方面结合起来的方法进行亲蟹培育和人工催熟:摘除亲蟹的单侧眼柄;投喂双壳类增加营养;控制水温在25℃～28℃,盐度30～32,pH值8.0～8.4,DO 5mg/L以上,光照强度0～1500 lx。本试验亲蟹的培育成活率达93.3％,抱卵率85.7％,孵化率83.3％。试验结果表明,甲长6.3～7.9 cm的雌蟹,经过培育,性腺均可发育成熟,均可抱卵。锈斑歸属一次性产卵类型,可多次抱卵。水体中聚缩虫等原生动物的大量繁殖直接影响锈斑(虫寻)胚胎和幼体的正常发育和孵化,也是幼体培育成活率低的原因之一。     

河蟹育苗生产中亲蟹的低温贮存技术

<正> 目前,我国北方地区的河蟹育苗生产中,大多利用亲蟹的多次抱卵习性,进行第二批及第三批的幼体孵化,以提高亲蟹及水体的利用率,达到高产的目的。但有时也会导致二次抱卵率低,抱卵量少,卵的质量差,孵出的Z1个体小,变态困难等现象。针对这一问题,我们于1998年春对前一年的越冬抱卵亲蟹通过用低温贮存、控制受精卵发育的方法,将亲蟹贮存到5月初,在第一批蟹苗出池后(5月初),再利用低温控制的亲蟹进行布苗、孵化,取得了成功,从而摆脱了以往的困境。现将这一贮存技术要点及操作规程作一介绍。     

梭子蟹亲蟹培育关键技术

我们经过多年梭子蟹人工育苗生产,总结出了在育苗中,亲蟹培育的一些关键技术。 1亲蟹选择选择已抱卵或未抱卵、规格300g以上、身体健壮、活力强、附肢完整、无伤、无杂物附着的海捕蟹作为亲蟹。未抱卵蟹要求已交配过,且卵已达到锯齿处;抱卵蟹     

河蟹多茬性抱卵饲育种苗生产技术研究

将１９９３年深秋收购的２７８公斤（３６１４只）未抱卵蟹进行了交尾，雌、雄配比３∶１，在一个１０亩土泥地内进行了露天越冬。１９９４年初春起捕，共收回亲蟹３３３９只，其中雄８８２只，雌蟹２４５７只，越冬成活率为９２％。在３—５月间，经河蟹的反复三茬性抱卵，均获得了成功。分别取得１茬抱卵亲蟹２２５５只，２茬抱卵亲蟹１４８２只，３茬抱卵亲蟹８０４只。三茬共收集孵化后状幼体３５６９３万只，饲育出大眼幼体蟹苗１６５公斤，总成活率为９．２％，取得经营收入达９４．５万元。     

环渤海地区长江蟹抱卵越冬问题与对策

近几年，长江蟹北称环渤海沿岸，抱卵越冬后作亲蟹，春天再大批量返供苗种，有力地促进了长江流域河蟹养殖业的发展。对在抱卵及越冬中发现的问题，我们进行了初步探究，并采取了积极对策，确保了亲蟹抱卵质量，提高了越冬成活率。１问题１．１滞后发育 生产中对比发现，在同样的培育条件下，长江蟹与当地河蟹相比，性腺或胚胎发育要滞后１０－１５天。１．２卵色异常与卵子退化 抱卵越冬中或在入室培育时发现，约有３．５％的抱卵蟹，其卵子为桔红色或桔黄色，并在培育中渐渐退化，镜检根本看不到正常发育的胚胎，不久，整个卵块变为粘团状…     

三疣梭子蟹土池越冬及亲蟹培育试验

在莱州湾南岸进行了三疣梭子蟹的土池越冬和亲蟹培育试验。越冬成活率６５．４％。亲蟹抱卵率５１．３％。比莱州湾自然蟹提前１个月产卵。     

广东省阳江地区野生拟穴青蟹2种病毒感染情况调查

青蟹双顺反子病毒-1（mudcrabdicistrovirus-1,MCDV-1）和青蟹呼肠孤病毒（mudcrabreovirus,MCRV）是对养殖拟穴青蟹有较强致病性的2种病原,可导致高死亡率。文章采用双重巢式PCR检测法对2012年阳江地区5月-10月捕捞的野生拟穴青蟹（Scyllaparamamosain）病毒感染情况进行调查。结果显示,阳江地区2012年5月～10月的野生青蟹群体一直保持较高的病毒携带率（44．83％-100％）,其中MCDV-1检出率最高的月份为6月、8月和9月,MCRV检出率最高的月份为5月-6月和8月～9月;以单独感染类型为主的月份为5月、7月和10月（〉44．83％）,以双阳性感染类型为主的月份为6月、8月和9月（〉82．76％）。由此可见,2种病毒的流行月份为5月～6月和8月～9月;在流行月份期间2种病毒常常协同感染野生拟穴青蟹。     

养殖锯缘青蟹黄水病流行病学及其预报模型

依据浙江三门县青蟹养殖基地青蟹黄水病发生及流行的定点观测资料和环境因子检测数据,对青蟹发病与养殖环境因子的关系进行了分析研究,找出3个显著影响青蟹黄水病发生与流行的环境因子,即盐度变化、降雨量和弧菌数量.在此基础上,用多元统计方法对黄水病的预报模型进行了研究,建立了三门县青蟹养殖基地的青蟹黄水病预报模型,(Y)=-0.088+0.00026TV+7.179SC.检验表明,该模型具较高拟合度,可以用来测报黄水病发病率.     

A reovirus disease in cultured mud crab, Scylla serrata, in southern China

A reovirus, designated mud crab reovirus (MCRV), associated with large economic losses was recently isolated from marine cultured mud crab, Scylla serrata, in southern China. The complete viral particle is 70 nm in diameter, icosahedral and non-enveloped. The virus infects connective tissue cells of the hepatopancreas, gills and intestine in mud crab and develops in the cytoplasm. Hundred per cent mortality was observed in mud crab experimentally infected by intramuscular injection, bath inoculation and oral inoculation, while cohabitation infection caused 80% mortality. The viral genome consists of 13 linear dsRNA segments, with an electrophoretic pattern 1/5/7. The results of this study suggest that the virus is highly pathogenic and can be transmitted enterically as well as via the body surface of mud crab. Although the genomic organization of this virus is different from that of the other crab reoviruses, CcRV-W2 and DpPV, all three of these reoviruses have similar electrophoresis patterns. Therefore, MCRV may be a new member of the DpPV and CcRV-W2 group.     

白斑综合征病毒(WSSV)在拟穴青蟹体内增殖的研究

拟穴青蟹(Scylla paramamosain)因肉质鲜美、生长快速而成为我国主要的海水养殖经济蟹类,但是随着养殖规模的不断扩大,病害问题也越发严重。本研究通过流行病学调查和定量PCR跟踪检测的方法,研究了拟穴青蟹对白斑综合征病毒(WSSV)的易感性和WSSV在拟穴青蟹体内的增殖情况。结果表明,拟穴青蟹是WSSV的自然宿主,自然携带率为8.47%。WSSV可通过口服途径感染拟穴青蟹,并在拟穴青蟹体内快速增殖,注射感染5 d后,病毒量达到感染1d时的1.1×109倍,当病毒累积到一定量后即可致死拟穴青蟹。研究表明,拟穴青蟹是WSSV的天然宿主,在虾蟹混养过程中可以通过摄食WSSV感染虾而带毒或发病,并因此成为WSSV传播媒介,从而对虾蟹混养条件下WSSV的防治效果产生重要影响。     

Studies on pathogenicity and prevalence of white spot syndrome virus in mud crab, Scylla serrata (Forskal), in Zhejiang Province, China

Mud crab, Scylla serrata (Forskal), is the most commercially important marine crab species in China. In recent years, serious diseases have occurred in major mud crab culture regions in SE China. PCR detection of white spot syndrome virus (WSSV) in diseased mud crabs collected from Zhejiang Province during 2006–2008 showed a prevalence of 34.82%. To study the pathogenicity of WSSV to mud crab, healthy mud crabs were injected intramuscularly with serial 10‐fold dilutions of a WSSV inoculum. The cumulative mortalities in groups challenged with 10^?1, 10^?2, 10^?3 and 10^?4 dilutions were 100%, 100%, 66.7% and 38.9% at 10 days post‐injection, respectively. All moribund and dead mud crabs except the control group were positive for WSSV by PCR. Based on the viral load of the WSSV inoculum by quantitative real‐time PCR, the median lethal dose (LD50) of WSSV in S. serrata was calculated as 1.10 × 10⁶ virus copies/crab, or 7.34 × 10³ virus copies g^?1 crab weight. The phenoloxidase, peroxidase and superoxide dismutase activities in haemolymph of WSSV‐infected moribund crabs, were significantly lower than the control group, whereas alkaline phosphatase, glutamate‐pyruvate transaminase and glutamic‐oxaloacetic transaminase were higher than in the control group. WSSV was mainly distributed in gills, subcuticular epithelia, heart, intestine and stomach as shown by immunohistochemical analysis with Mabs against WSSV. The epithelial cells of infected gill showed hypertrophied nuclei with basophilic inclusions. Numerous bacilliform virus particles were observed in nuclei of infected gill cells by transmission electron microscopy. It is concluded that WSSV is a major pathogen of mud crab with high pathogenicity.     

锯缘青蟹血清凝集素的特性和盐析提取研究

对锯缘青蟹(Scylla serrate)血清凝集素的凝集特性进行了研究。结果显示:锯缘青蟹血清凝集素对人、兔、鼠、鸽子、中华鳖、鲫红细胞均有凝集作用,其中对小鼠红细胞凝集活性最强,血凝活性可达29;凝集素活性最适pH 6.0~7.4;盐度对凝集活力有较大影响,NaC l浓度在0.4~0.5 mol/L时基本失活;未纯化血清凝集素对Ca2+、Mg2+未表现出依赖性;凝集素活性能被N-乙酰葡萄糖胺特异性抑制。对青蟹血清凝集素进行硫酸铵分级沉淀分离后,发现凝集素活性主要分布在25%饱和度硫酸铵沉淀区,该组分凝集比活比血清高27.44倍,SDS-PAGE结果表明主要蛋白带型为79 ku、75 ku、72 ku。     

我国蟹类土池育苗技术研究进展

蟹类养殖产业已成为我国水产养殖的支柱产业之一。中华绒螯蟹(Eriocheir sinensis,以下简称河蟹)、三疣梭子蟹(Portunus trituberculatus,以下简称梭子蟹)、拟穴青蟹(Scylla paramamosain,以下简称青蟹)是我国主要的养殖蟹类。目前3种蟹类土池育苗技术发展不平衡,河蟹、梭子蟹土池育苗技术较为成熟,已经普及推广并在养殖生产中发挥重要作用;青蟹土池育苗尚未有成功的报道。本文综述了我国河蟹、梭子蟹、青蟹苗种生产技术,尤其是土池育苗技术的研究进展,并对河蟹、梭子蟹土池育苗关键技术进行分析,旨在探讨蟹类土池育苗技术应用于青蟹土池育苗的可行性。     

Social and economic implications of small-scale mud crab (Scylla serrata) aquaculture: the case of organised community groups

Small-scale mud crab aquaculture was introduced in East Africa in late 1990s as a mangrove friendly aquaculture to improve the livelihood of coastal communities through organised community groups (OCGs). The OCGs approach was a strategy aimed at ensuring benefits to the village and regulating access to the open access resource (land in mangrove forests). A social and economic assessment was conducted at Majaoni, Makongeni, Ihaleni and Dabaso along the Kenyan coast. The paper looks at the social and economic characteristics of the groups, their management systems, contribution of mud crab aquaculture to the livelihoods of local communities and policy issues related to the interventions. There is wider involvement of the mijikenda community in mud crab farming; however, the level of women participation is low. A strong market link exists between the groups and the different market outlets, where hotels and exporters offer the highest prices. Regional price variations existed and may need networking between the groups. The paper concludes that national policies may need to be redirected to support small-scale aquaculture development and ensuring capacity building for women, operation and management of groups, provision of extension services, data management and provision of user rights for communities working in the mangrove environment.     

应用PCR方法检测患“黄水病”锯缘青蟹中的血卵涡鞭虫

"黄水病"是目前锯缘青蟹养殖过程中的主要疾病之一,病蟹主要症状表现为肌肉白浊,体液呈土黄色或浊白色牛奶状。因该病流行范围广、发病率和死亡率高,给青蟹养殖业主造成巨大经济损失,严重地影响了青蟹养殖的健康发展。本研究从病蟹体液中发现大量疑似血卵涡鞭虫的寄生原虫,应用已建立的梭子蟹血卵涡鞭虫病的PCR检测方法对患"黄水病"青蟹进行检测。结果从患病青蟹组织的DNA中扩增出产物大小为585bp的特异性目的片段,经序列分析比较,与三疣梭子蟹上发现的血卵涡鞭虫的序列同源,同源性达99.7%。综合病原流行病学调查、组织病理学、电镜观察等分析结果,初步确定血卵涡鞭虫是引起养殖青蟹"黄水病"的重要病原。