氨和亚硝酸盐对于对虾幼虫的毒性

氨是甲壳类动物中蛋白质分解代谢的主要最终产品,而且在含氮排泄物中氨占总量的40％—90％。氨由非离子氨NH_3和离子氨NH4_~+组成,非离子氨是非极性化合物,有相当大的脂溶性,能穿透细胞膜毒害组织。氨又经常会氧化成亚硝酸盐和硝酸盐。非离子氨和其中间产品(亚硝酸盐)对鱼和甲壳类动物是有毒性的。在封闭的海水养殖系统中,氨和亚硝酸盐的积累对于虾和其幼虫有污染影响。因此,在封闭海水养殖系统中,了解氨和亚硝酸盐的积累,在对虾孵化场是极为重要的问题。     

氨和亚硝酸盐对中国对虾稚虾的毒性

对虾的排泄物和废饵或有机碎屑生氨作用产生的氨有很大的毒性。由氨被亚硝化单胞菌形成的亚硝酸盐对于甲壳类动物比氨有更大的毒性。氨和亚硝酸盐在养殖系统中由氮所形成的两种主要无机物,可以污染水质,导致对虾的高死亡率和低的生长。因此,这些毒素的积累及其有毒作用是精养系统中十分关注的问题。     

湛江湾沉积物中反硝化和厌氧氨氧化细菌的丰度、多样性及分布特征

采用实时荧光定量PCR、高通量测序等方法对湛江湾沉积物中四个月份的反硝化细菌与厌氧氨氧化细菌的多样性和丰度进行了分析。结果表明:湛江湾沉积物中反硝化细菌和厌氧氨氧化细菌丰度在四个月份的变化和空间分布趋势为:nirS型反硝化细菌在二月份最高,四月份最低,且其平均丰度有从湛江湾湾内向湾口附近呈现先升高再降低的趋势;nirK型反硝化细菌丰度在九月份最高,十一月份最低;nosZ型反硝化细菌在四月份最高,其余月份变化不大;厌氧氨氧化细菌丰度在九月份最高,二月份最低。通过相关性分析结果表明,亚硝酸盐、铵盐等共同调控着湛江湾沉积物中反硝化和厌氧氨氧化细菌丰度变化。系统发育分析表明:湛江湾中存在着一些广泛分布的反硝化细菌,但也生活着一些新奇的nirK型和nosZ型反硝化细菌。对于厌氧氨氧化细菌而言,其主要属于浮霉菌门及Candidatus Scalindua属,具有较高的耐盐性,另外湛江湾海区的厌氧氨氧化细菌也生活着一类在其他地方没有的新分支。典范对应分析分析结果表明:硝酸盐显著影响湛江湾反硝化细菌和厌氧氨氧化细菌的群落结构。湛江湾沉积物中反硝化细菌和厌氧氨氧化细菌存在特殊的竞争与共存的关系,且由亚硝酸盐、硝酸盐、pH等多种环境因子共同驱动。     

光合细菌净化对虾养殖水质的研究

养殖水体中大量氨氮，硫化物的产生以及溶解氮的降低严重影响了对虾的正常生长。本文报道了光合细菌在实验室环境中净化水质的情况，结果表明，光合细菌参降低养殖水体中的氨氮和Ｈ２Ｓ含量，并提高水体中溶解氧的含量。     

海洋沉积物中反硝化细菌的分离及去除硝酸盐氮的模拟试验

从长江口沉积物中筛选分离出了海洋反硝化细菌,模拟了该细菌对不同浓度水平硝酸盐氮的去除效率。研究结果表明,分离出的海洋反硝化细菌能有效去除海水中硝酸盐氮,在硝酸盐氮的初始浓度为 1 mg/L,1 d 内硝酸盐氮去除率就达到了 70 %;在 100 mg/L 硝酸盐氮模拟试验中,约在一周内能将 90 % 硝酸盐氮去除。试验证明反硝化细菌的生长与水体中硝酸盐氮浓度有一定的相关关系,一旦生物修复过程完成,反硝化细菌就会大量死亡,水体重新恢复到清澈透明状况。     

池塘淤泥对水中氮营养盐影响的初步研究

通过对不同厚度淤泥水中氮营养盐的测定和分析,初步研究了不同厚度淤泥对水族箱水质环境中氮营养盐的影响。实验结果表明,有淤泥水族箱水中的氨氮浓度与无淤泥水族箱水中氨氮浓度差异显著,且有淤泥水中的氨氮浓度变化幅度较小。有淤泥水族箱水中硝酸盐和亚硝酸盐浓度显著高于无淤泥水体,10cm厚淤泥水中亚硝酸盐浓度变化较5cm厚淤泥水体稳定。由此说明,养殖水体需要一定厚度的淤泥来维持和缓冲水体中各营养盐水平。     

氨及亚硝酸盐对真鲷仔鱼的急性毒性研究

氨是水产动物蛋白质代谢的最终产物,亚硝酸盐是氨硝化作用的中间产物。在养殖系统中氨及亚硝酸盐都有可能积累到使鱼放毒的程度。因而了解养殖对象对氨及亚硝酸盐的忍耐程度是必需的。     

刺参-对虾复合养殖系统主要营养盐动态变化及循环过程的研究

2011年4～9月期间对养殖系统N、P营养盐含量进行连续采样分析,比较刺参单养(S池塘)和刺参-对虾复合养殖(SS池塘)2种模式养殖系统水体、沉积物、底泥营养盐的动态变化及循环过程。结果表明,水体中总氮(TN)含量为:S池塘(1.16±0.13)～(2.64±0.09)mg·L-1;SS池塘(1.24±0.08)～(2.55±0.09)mg·L-1。水体中总磷(TP)含量为:S池塘(0.03±0.01)～(0.08±0.01)mg·L-1;SS池塘(0.03±0.01)～(0.09±0.02)mg·L-1。水体中总无机氮(DIN)含量为:S池塘(0.10±0.03)～(0.32±0.05)mg·L-1;SS池塘(0.16±0.03)～(0.45±0.02)mg·L-1。3种营养盐浓度并未随着养殖活动的进行而持续升高,反而下降,说明这2种养殖模式均不会增加养殖水体营养盐负荷。2个池塘底泥的TN、TP含量从实验开始到结束均未发生显著变化(P>0.05),说明这2种养殖模式均不会增加养殖池塘底泥N、P营养盐的积累。各营养盐指标相关分析结果显示,两池塘底泥氨氮与水体氨氮呈显著负相关(P<0.05),说明氨氮在池塘底泥与水体之间存在交换作用,并且刺参和对虾的扰动作用可能促进这一交换过程。8和9月刺参处于夏眠期,SS池塘水体颗粒氮(PN)显著低于S池塘(P<0.05),水体颗粒物的沉积通量也相对增大,底泥氨氮含量显著低于S池塘(P<0.05),而水体氨氮、DIN、TN浓度均高于S池塘,说明刺参-对虾复合养殖池塘中,因混养对虾的生物沉积与扰动作用,加强了养殖系统内水体与底泥之间的偶联作用,加快了营养盐的循环过程,防止营养盐在底泥的连续积累造成的养殖环境恶化。     

养殖水体营养状态及自净能力的分析

本文根据１９９７年２～１２月间对对虾 养殖水全的监测结果,应用营养指数法进行养殖水体的营养水平评价,结合自养指数对水体的自净能力进行分析。结果表明,养殖水体内具有较高的ＤＩＰ和ＣＯＤ是造成水体富营养化的主要因素。较高的Ｃｈｌ－ａ含量则是富营养化水体的表现。养殖池内水质状况同养殖周期和季节变更密切相关。养殖水体浮游值物和微生物的代谢偶联,是反映水体自净能力,保持水体稳定的基础。     

纳米生态基在凡纳滨对虾养殖中的应用研究

研究了凡纳滨对虾集约化养殖池塘中挂设不同密度的纳米生态基对养殖水质及对虾生长的影响。试验共使用12口养殖池,生态基的挂设密度分别为0.029,0.043和0.058 m2/m3水体,以不挂设纳米生态基的养殖池为对照。结果表明,挂设纳米生态基能明显降低养殖水体的氨氮、亚硝氮和COD含量,挂设生态基处理组池塘水体中氨氮与对照组之间差异显著(P0.05),亚硝氮在试验第7 d后差异显著(P0.05);纳米生态基能较好的稳定池塘水体的DO水平,增氧时DO增加速度与挂设生态基的密度成正比,增氧关闭时DO减小速度与挂设生态基的密度成反比;生态基能提高凡纳滨对虾产量并有效降低其饵料系数,对虾产量分别比对照组高出0.8%,15.3%,3.2%,饵料系数分别降低17%,40%,26%。当对虾放苗密度为150尾/m2时,在本研究设计的梯度范围内,生态基的最佳挂设密度为0.043 m2/m3水体。     

久效磷对中国对虾血淋巴酚氧化酶活力影响的初步研究

初步研究了低浓度久效磷胁迫对中国对虾胁迫对中国对虾血淋巴酚氧化酶（ＰＯ）活力的影响,结果表明,低浓度久效磷短时间胁迫,对中国对虾血淋巴的ＰＯ活力有刺激增强的作用;增大药物浓度和延长胁迫时间,可使其活力降低,且随药物浓度的增加和胁迫时间的延长,这种降低作用逐渐增强。因此认为,久效磷胁迫会抑制机体识别和清除病原体的能力,将可能导致对虾疾病的发生,是虾病暴发的可能诱因。     

Detoxification mechanisms in shrimp: comparative approach between hydrothermal vent fields and estuarine environments

Hydrothermal vents are extreme deep-sea habitats that, due to their singular features, still intrigue scientific communities. Swift growth rates and profuse biomass of biological communities can be observed, despite of their inherently unstable physical-chemical and toxic conditions, indicating that organisms inhabiting this environment must be well adapted to these inhospitable conditions. The caridean shrimp, Chorocaris chacei, Mirocaris fortunata and Rimicaris exoculata, together with bathymodiolid mussels, dominate the vent fauna along the Mid-Atlantic Ridge (MAR). Crustacean species are widely used as biological indicators of environmental alterations, since they play a key ecological role as planktivorous grazers, epibenthic scavengers or as prey species. The biological consequences of the hydrothermal metal-rich environment in shrimp species are still largely unknown. Therefore, the aim of this study was the determination of the metal levels (Ag, Cd, Cu, Fe, Mn and Zn), metallothioneins (MT) and lipid peroxidation (LPO) in shrimp species collected in Rainbow, Lucky Strike and Menez-Gwen vent sites, in order to evaluate their different adaptation strategies toward metals when compared with two common coastal shrimp species (Palaemon elegans and Palaemonetes varians) from a fairly unpolluted estuarine system in south Portugal (Ria Formosa). Results show significant differences in metal concentrations, MT levels and lipid peroxidation between vent and coastal shrimp and also between shrimp species from the same site. This indicates that biochemical responses in both vent and coastal shrimp are affected not only by the environmental characteristics but also by inter-specific differences. Nevertheless, these responses apparently grant a successful adaptation for the survival in a metal-extreme environment.     

Toxic contributions of specific drilling mud components to larval shrimp and crabs

We investigated the toxicities of six drilling muds, toxicities of mud fractions (supernatants and suspensions) and the toxicities of common mud components—barite and bentonite (particulates) and ferrochrome lignosulfonate (soluble)—to the stage I larvae of six species of shrimp and crab. The drilling muds we tested were not very toxic to these larvae: LC₅₀'s for supernatants ranged from 0·6 to 82% (vol/vol). Shrimp larvae were slightly more sensitive than crab larvae.Drilling muds were not rapidly toxic, in contrast to toxicants such as the water-soluble fractions of oil. Supernatants, prepared by centrifuging whole muds, were mildly toxic. Suspensions were more toxic than supernatants and toxicity was greatest when particulates remained suspended: for example, used Cook Inlet mud suspensions were about seven times more toxic than supernatants. The toxicity of used Cook Inlet mud was therefore primarily due to suspended solids (88%) rather than chemical toxicity: ferrochrome lignosulfonate was relatively toxic alone, but accounted for only about 6% of the toxicity of used Cook Inlet mud suspensions. Contributions of particulates to mud toxicities varied considerably. Barite and bentonite were not very toxic when tested alone. The toxicity of one mud was caused by its high alkalinity.     

我国对虾养殖净收益影响因素分析

海水养殖是海洋经济重要的组成部分。中国是世界上最大的对虾养殖国,对虾养殖净收益直接影响对虾养殖户的生产积极性,进而影响对虾养殖产业持续稳定健康发展。文章以山东省、江苏省和广东省对虾养殖户的调查数据为依据,运用多元线性回归模型,对对虾养殖净收益的影响因素进行实证分析。结果表明,影响对虾养殖净收益的3个主要因素是:①每年对虾养殖的造数;②是否参加对虾养殖农业合作社;③对虾出塘的销售价格。对虾养殖者的年龄,受教育程度,是否混养其他品种生物,养殖模式,养殖面积对对虾养殖净收益影响不显著。基于回归结果,笔者提出完善对虾养殖基础设施;发展对虾养殖农业合作社和养殖协会;建立稳定的对虾市场价格调控体系等政策建议。     

Expression and activity of glutathione S-transferases and catalase in the shrimp Litopenaeus vannamei inoculated with a toxic Microcystis aeruginosa strain

Microcystin (MC) produced during cyanobacteria blooms is notably toxic to human and wildlife. Conjugation with reduced glutathione (GSH) by glutathione S-transferase (GST) and the antioxidant enzymes defenses (e.g. catalase, CAT) are important biochemical defense mechanisms against MCs toxicity. We investigated the enzymatic activity of CAT and GST and the gene expression levels of CAT and eight GST isoforms in the hepatopancreas of the globally farmed shrimp Litopenaeus vannamei 48-h after injection with a sub-lethal dose of 100 μg kg⁻¹ of a toxic Microcystis aeruginosa extract. MCs caused up-regulation for GST Ω, μ and a MAPEG isoform, by 12-, 2.8- and 1.8-fold, respectively, and increases in the total GST enzyme activity and CAT enzyme activity. The study points to the importance of further characterization for the L. vannamei GST isoforms and GST/CAT post-translational regulation processes to better understand the key mechanisms involved in the shrimp’s defense against MC exposure.     

东南亚养虾之现况与展望

东南亚是世界虾类养殖的重心地区,而白虾已成为世界养虾中最重要的虾种.中国为世界养虾产量最多的地区.在东南亚的养虾中,白虾的产量占总产量的比例从2004年的62%增加到2006年的76%,而草虾产量占总产量的比例则从38%减少到24%.但是印度、印度尼西亚与孟加拉国等地区的草虾产量不减反增,其中以印度为最,这与当地低密度的放养方式生产的较大体形的草虾有关.美国和日本的养虾产量由于供过于求,故虾价仍缓慢下跌,若养殖业者能把握虾价较高的季节(9月至次年1月)并生产大型虾类,则养殖利润仍高,越南的草虾即为一例.文中还提及白虾超高密度养殖的成功方法,许多地区的每季白虾生产可达40t·hm<'-2>以上;淡水区白虾养殖可不必加以禁养,因其对环境的危害影响仍不明显.本文最后还提出发展虾类养殖的科研重点,以供有识者参考.     

中国对虾丝状细菌的扫描电镜研究

本文应用扫描电镜研究了中国对虾丝状细菌的结构,附着方式及其对对虾的危害和与环境的关系。     

Dioxin compounds in the deep-sea rose shrimp Aristeus antennatus (Risso, 1816) throughout the Mediterranean Sea

Polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs) are among the more toxic anthropogenic contaminants. They are fat-soluble and accumulate in animal tissues. Exposure to PCDD/Fs can cause several endocrine, reproductive and developmental problems in animals, including human beings. Several studies have demonstrated that fish and invertebrates living in association with sediments are exposed to and accumulate contaminants, but to date there have been no studies of PCDD/Fs contamination in deep-sea regions. Specimens of Aristeus antennatus (Risso, 1816) were collected from depths of 600–2500 m at different points in the Mediterranean Sea, from the western basin off the coast of Barcelona to the central basin off the Peloponnesian Peninsula, with otter trawl gear. Amounts of PCDD/Fs were measured in different animal tissues by high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC–HRMS). This is the first study to report the presence of PCDD/Fs in deep-sea organisms dwelling at depths below 600 m. A. antennatus presented levels of PCDD/Fs of the same order of magnitude, or slightly higher, as those found in shallow-water species (Melicertus kerathurus) with respect to land-generated contamination. This highlights the widespread distribution of these pollutants and the potential threat posed to the biodiversity of fragile and vulnerable ecosystems such as the deep-sea. PCDD/F levels detected in the edible parts (muscle) of the commercial shrimp A. antennatus were clearly below the toxic limit value established by European legislation. Levels followed the trend muscle<ovary<hepatopancreas, according to the lipid content of the organs in question. The specific profile of toxic PCDD/F congeners in the studied Penaeid shrimp specimens was characterized mainly by octachlorodibenzo-p-dioxin (OCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF) and 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) congeners. Moreover, non 2,3,7,8-substituted congeners bioaccumulated in this species, as observed in shallow-water crustaceans. PCDD/Fs were found in the shrimp A. antennatus throughout the Mediterranean Sea. Total PCDD/Fs burdens were higher in shrimps caught in the western Mediterranean than in those caught at eastern Mediterranean sites. There was a tendency for higher levels of PCDD/F contamination in samples obtained from deeper (2500 m) than from shallower sites (600 m).     

Shrimp aquaculture: economic perspectives for policy development

The objective of this paper is to provide an overview of shrimp aquaculture from the perspectives of economics. It is offered as a contribution to the on-going policy debate on this globally important industry. The paper is organised into four sections: the benefits of shrimp aquaculture, the problems of shrimp aquaculture, economic development perspectives on shrimp aquaculture, and conclusions. Four main conclusions are drawn: there is a lack of independent analysis of the factors affecting the production strategies of private firms in the shrimp industry; there is a need to overcome polarisation in order to promote sustainable shrimp aquaculture; wider perspectives on shrimp aquaculture will be beneficial to policy formation; and it is in the long-run self-interest of shrimp producers to incorporate the external costs of production into planning decisions. The paper includes a review of the international literature which provides a valuable resource for policy-makers.     

白斑综合症杆状病毒致病性特征

对白斑综合症杆状病毒（ＷＳＢＶ）致病性特征的研究结果表明：ＷＳＢＶ的致病性与斑节对虾Ｐｅｎａｅｕｓｍｏｎｏｄｏｎ个体大小无关,ＷＳＢＶ的致病力与感染方式和病毒数量有关;在盐度为１４、温度为２８－３２℃的海水中,游离ＷＳＢＶ在４ｈ内失去感染活性;体长７ｃｍ的白斑综合症死亡斑节对虾,其携带的ＷＳＢＶ在５７ｈ失去感染活性;体长７ｃｍ死亡斑节对虾经２８℃空气干燥,其携带的ＷＳＢＶ在５０ｈ失去感染活性;ＷＳＢＶ不能通过体表感染健康斑节对虾,而斑节对虾摄食一定数量病毒才能导致感染;水不能作为游离ＷＳＢＶ的载体传播ＷＳＢＶ。