Effects of different types of nutrient effluent from shrimp ponds on the seedling growth of Kandelia obovata

Extensive shrimp ponds are located next to the landward edges of most of mangrove forests in China. A shrimp pond may influence mangroves by（1） routine effluent between pond and tide, and（2） dredging effluent from pond-dredging at least once a year. Our study consisted of two experiments to study the effects of these two effluents on the seedling growth of Kandelia obovata. One experiment simulated the effects of routine effluents.The other simulated four sedimentation thicknesses（0 cm, 2 cm, 4 cm, 8 cm） over mangrove soils by dredging effluent from pond-dredging, and revealed the cumulative effects of dredging effluents on K. obovata. At each of the three fixed salinities, i.e., 5, 15 and 25, routine effluent did not result in significant differences in each of the measured growth parameters of K. obovata seedlings. However, effects of dredging effluent on seedling growth of K. obovata were related with sedimentation thickness. Most growth parameters showed maximum values at sedimentation thickness 4 cm. The data indicated that K. obovata accelerated its growth under moderate sedimentation thicknesses and it was tolerant and adaptable to shrimp pond-cleaning effluent sediments up to about 8 cm in our experiment.

GROWING NIPA PALM FOR RESTORATION OF ABANDONED SHRIMP PONDS

Rapid increase in the production of marine shrimps in the coastal zone has resulted in large-scale con-version of mangrove forests to shrimp ponds.Productions of the shrimps in some regions have been unstable.Conse-quently,a number of ponds are left idle.Restoring environmental conditions within the pond site by planting a suitablemangrove species considered an option.The experiment herein was carried out to explore the effect of planting methodson growth of Nipa palm in abandoned shrimp ponds in the Southern Thailand.Economically,coastal villagers in this areaearn their income from the palm in several ways,the most importantly in Nipa sugar production.Most seedlings wereplanted on top of furrows were constructed in the pond to avoid flooding,except for some seedlings which were planted inthe pond base where additional pond sludge were slightly filled up to compare their growth rates.The results showed thatplanting seedlings with attached rhizomes had the best growth rate and without seedling death at 14 months after plant-ing.At this stage,however,the height of seedlings grown from the fallen fruits was similar to those growth from barerooted seedlings(70 cm tall).Also,seedling mortality was not observed when growth from fallen fruits whereas about6% mortality was experienced by the bare rooted ones.Among the bare rooted seedling treatments,however no signifi-cant differences in growth rates were found when applying the soil with chemical fertilizers or farm manure or liming withCaCO3.In addition,it was found that seedling growth measured at 40 months after planting for those growths in pondbase was almost100% greater than those grown on the furrows.Therefore,this finding may be applied for the restorationof abandoned shrimp ponds by growing Nipa palm.

Supplement and Consumption of Dissolved Oxygen and Their Seasonal Variations in Shrimp Pond

On the basis of the research of DO budget or kinetics in shrimp pond, the main influence process of DO and its seasonal variations are quantitatively described through redividing the budget process and modifying the quantitative method of the process. The percentages of oxygen demand of various processes in the total oxygen demand are different in shrimp cultivation seasons. It is showed that the dissolved oxygen demand of mini-organisms is the major affected factor of DO in this environment and approximately accounts for 64.1～74.1% of the total oxygen demand. In the early period of shrimp culture, the dissolved oxygen demand of allotrophic bacteria degrading organic matters is much lower than that of phytoplankton respiration. But in the midterrn and later period, it is about 50% of the total oxygen demand because of the higher water temperature and more serious self-pollution. The dissolved oxygen demand of sediment is lower and just 19.1～28.8%, while the percentage of shrimp oxygen demand is lower. The effect of phytoplankton on DO in shrimp culturing water has dualism. One is the oxygen producing process of photosynthesis and the other is the oxygen consumption process of respiration. It is estimated that the dissolved oxygen demand of phytoplankton respiration is approximately one-fifth of the oxygen produced by photosynthesis under normal illumination conditions. The dissolved oxygen demand of al lotrophic bacteria degrading organic matters and the total oxygen demand of sediment increase 4 times and 1.7 times respectively from the early period to the midterm and later period.Obviously, the DO of culturing water can be also greatly improved by controlling the selfpollution of organic matters during shrimp culture.

A Study on the Contribution of Different Food Sources to Shrimp Growth in an Intensive Fenneropenaeus chinensis Pond

Stable isotope methods can be used to determine the food sources and prey items of aquatic organisms accurately and reliably. This study examined the relative contribution of artificial foods （the formulated feed and Arternia） and natural foods to shrimp growth in an intensive Fenneropenaeus chinensis pond by using carbon and nitrogen stable isotopes. The results showed that the nutrition utilization efficiency of the harvested shrimp was low, only 33.18% of feed nitrogen and 21.73% of feed carbon being converted to shrimp flesh, Our stable isotope results showed that the shrimp obtained nutrition for maximum growth from artificial foods, whose contribution was 93.5%, with the remaining attributed to the natural foods. However, there was 0.94t harvested shrimp derived from natural foods （the rest of 13.56t harvested shrimp derived from artificial foods） in lha intensive pond with a shrimp production of 14.50 tha^-1. Therefore, unit area shrimp production can be increased by increasing the contribution proportion of natural foods in intensive shrimp farming.

Heterosis and heritability estimates for the survival of the Pacific white shrimp(Litopenaeus vannamei) under the commercial scale ponds

The aim of the present study is to detect the potential of the base population from diallel crosses of eight introduced strains of the Pacific white shrimp（Litopenaeus vannamei） for improving the yield. Heterosis and heritability were estimated for pond survival at commercial farm conditions for the base population that included 207 full-sib families from a nested mating design by artificial insemination. Among all the hybrids,the heterosis ranged from –11.37%（UA1×UA2） to 20.53%（UA3×SIN） with an average of 0.953%. The results showed that more than half of the hybrids（51.85%） have negative heterosis for survival rate, but most of the hybrids with positive heterosis have high estimates. The high proportion of negative heterosis for survival rate reminders us that the survival trait also should be considered in the crossbreeding program to avoid yield decrease. However, high positive heterosis manifested in most of the hybrids for survival indicates the usefulness of these hybrids for improving the survival to obtain higher yield by crossbreeding in this breeding program. The heritability estimate for pond survival was 0.092±0.043 when genetic groups were included in the pedigree, and it was significantly different from zero（P〈0.05）. The results from this study also indicated that significant improvement for survival is possible through selection in L. vannamei.

Effects of Rice-Fish Co-culture on Oxygen Consumption in Intensive Aquaculture Pond

Rice-fish co-culture has gained increasing attention to remediate the negative environmental impacts induced by intensive aquaculture. However, the effect of rice-fish co-culture on oxygen depletion has rarely been investigated. We constructed a rice-fish co-culture system in yellow catfish(Pelteobagrus fulvidraco) and freshwater shrimp(Macrobrachium nipponense) ponds using a new high-stalk rice variety, and conducted a field experiment to investigate the effect of rice-fish co-culture on water parameters and oxygen consumption. The results showed that rice-fish co-culture reduced the nutrients(total nitrogen, ammonia-N, total phosphorous and potassium) and the dissolved oxygen content in fish and shrimp ponds. However, they showed similar seasonal change of dissolved oxygen in the water of fish and shrimp ponds. Rice-fish co-culture reduced the total amount of oxygen consumption and optimized the oxygen consumption structure in pond. The respiration rates in water and sediment were significantly reduced by 66.1% and 31.7% in the catfish pond, and 64.4% and 38.7% in the shrimp pond, respectively, by additional rice cultivation. Rice-fish co-culture decreased the proportions of respiration in sediment and water, and increased the proportion of fish respiration. These results suggest that rice-fish co-culture is an efficient way to reduce hypoxia in intensive culture pond.

海水垂向入侵问题研究进展

随着全球气候变暖,风暴潮在沿海地区的频率和强度均可能增长,由此引发的海水垂向入侵可能会造成大面积的含水层淡水咸化。同时,由人类活动引起的沿海虾塘咸水养殖规模日益增长,由此引发的咸水垂向入侵可能会导致沿海地区地下水水质及生态环境的恶化。虽然已有一部分学者在海水(咸水)垂向入侵的研究中取得了成果,但由于海水(咸水)垂向入侵过程复杂,其对地下水咸化及恢复规律依然有待深入研究。文章阐述了海水垂向入侵的危害及前人的研究办法,总结了他们的研究成果并得出了海水垂向入侵的影响因子,指出了洪水和养殖活动对沿海地区含水层的威胁。得出的结果如下:研究海水垂向入侵常用的方法包括室内试验和数值模拟;海水垂向入侵主要与地形地貌、含水层性质和水文气象条件有关;虾塘养殖等人类活动可能会成为垂向咸水入侵的潜在来源。建议未来在海水垂向入侵研究中将多种现场观测实验方法结合起来。数值模拟应注重与现场观测实验数据相互验证,模型简化的方式有必要仔细考虑。虾塘养殖等人类活动可能造成的垂向咸水入侵问题应更多地受到关注。

西施舌人工繁育研究

开展了西施舌人工繁育研究。以3~4龄西施舌为亲贝,采用“封闭育苗”模式进行浮游幼虫和稚贝的培育,采用“附着板+池底”附苗模式进行采苗。结果表明,亲贝经过诱导、授精和孵化,获总卵量4536.99万粒,受精率达到(87.01±2.57)%,获受精卵3947.63万粒。经过胚胎发育阶段至初期面盘幼虫(D型幼虫),获D形幼虫3631.41万粒,孵化率达到(91.99±3.46)%。浮游幼虫壳长生长速度(9.92±0.26)μm/d,壳高生长速度(10.19±0.41)μm/d,浮游幼虫的存活率(84.26±3.78)%。经12~17d,浮游幼虫完成附着变态,形成初期稚贝。经30 d的培育,获得(3.26±0.12)mm×(3.10±0.09)mm的出池稚贝617.34万粒,稚贝成活率(17.00±1.93)%。经过约45 d的培育,获得(2.15±0.07)cm×(2.04±0.03)cm的西施舌中培苗(幼贝)257.99万粒,中培成活率为(41.79±2.51)%。指出,“附着板+池底”附苗模式可以取得较好的采苗效果,“封闭育苗”模式适于作为西施舌从浮游幼虫至幼贝的培育模式。

北海市虾塘海水养殖对地下水环境的影响与保护对策研究

通过开展中国地质调查局“北部湾经济区南康盆地地下水资源潜力评价”项目,文章梳理出了北海市所在的南康盆地地下水成因以及拟采取的保护措施,结合北海市虾塘海水养殖等经济发展方式所造成的对周围地下水环境的污染影响,提出在规划选址、海水养殖场建设以及养殖场运营期方面的地下水保护对策及措施,对北海市今后经济发展与地下水环境保护具有切实的指导意义。

海水养殖沉积环境微生物总DNA的提取方法研究

传统的微生物分离与培养技术：无法揭示微生物群落的动态变化．为了阐释虾池沉积环境微生态格局的原始组成情况，本研究先以TENP缓冲液去除沉积物中的腐殖酸。继之以溶菌酶-SDS温和裂解，其总DNA的提取效率达90％以上．所获DNA产量达2～20μg／g沉积物（湿），片段大小均在23kb左右，不经纯化即可直接进行PCR扩增和限制性酶切．以该DNA为模板进行PCR—DGGE分析，揭示了虾池沉积物丰富的微生物多样性，该方法是一种适用于虾池沉积物总DNA提取的简便、可靠方法．

厦门杏林虾池夏冬季微型浮游动物对浮游植物的摄食压力

20 0 0年 8月和 2 0 0 1年 2月 ,在杏林虾池用稀释法研究了微型浮游动物对浮游植物的摄食压力 .结果表明 :砂壳纤毛虫、甲壳类无节幼体是微型浮游动物的优势种 ;浮游植物生长率夏季为 0 .40～ 1 .0 1 /d、冬季为 0 .1 8～ 0 .96/d ;浮游动物的摄食率夏季为 0 .578～ 1 .3 2 4/d、冬季为 0 .2 0 4～ 0 .2 55/d ;日摄食率 (以C计 )夏季为 1 9.1 7～89.51mg/(m3·d)、冬季为 3 .3 2～ 7.2 3mg/(m3·d) ,各占浮游植物现存量的 43 .90 %～ 73 .40 %、1 8.43 %～ 2 2 .51 %;对初级生产力的摄食压力夏季为 1 1 5.2 3 %～1 93 .52 %、冬季为 3 7.47%～ 1 1 1 .3 1 %.

对虾池不同综合养殖系统效率和效益的比较研究

利用５０个５．０×５．０×１．８ｍ陆基围隔研究了中国对虾与台湾红罗非鱼、海湾扇贝和缢蛏投饵或施肥混养及鲈鱼与中国对虾和台湾红罗非鱼混养最佳结构的生态效率、生产效果和经济效益。结果表明，几种综合养殖系统最佳结构下各种养殖对象对Ｎ的绝对利用率由高至低依次为：鲈鱼－对虾－罗非鱼（３０．９１％）＞对虾－海湾扇贝（２１．０９％）＞对虾－罗非鱼施肥混养（２０．１２％）＞对虾－罗非鱼投饵混养（１７．８１％）＞对虾－缢蛏（１６．９３％）＞单养对虾（１１．５２％）；对Ｐ的绝对利用率由高至低依次为：对虾－缢蛏（１６．０８％）＞鲈鱼－对虾－罗非鱼（１２．８３％）＞对虾－罗非鱼投饵混养（１２．６３％）＞单养对虾（１０．８８％）＞对虾－海湾扇贝（６．０１％）＞对虾－罗非鱼施肥混养（４．０４％）；其产出投入比由高至低依次为：对虾－罗非鱼投饵混养（１．９９）＞对虾－罗非鱼施肥混养（１．９８）＞对虾－海湾扇贝（１．５３）＞单养对虾（１．３８）＞鲈鱼－对虾－罗非鱼（１．３０）＞对虾－缢蛏（１．２３）。

强降雨对粤西凡纳滨对虾养殖池塘微生物群落的影响

于强台风"莫拉菲"环流云系带来的持续强降雨天气前后(2009年7月14日和7月28日),对广东省茂名市电白县凡纳滨对虾半集约化养殖土池的水样和泥样进行调查,研究施用微生态制剂和未施用微生态制剂的虾池水体及底泥中的异养细菌、弧菌和芽孢杆菌的变化情况,并利用BIOLOGECO微板对水体和底泥的微生物群落代谢变化进行探讨。结果发现,定期施用微生态制剂的虾池水体和底泥中的细菌数量和微生物群落功能在强降雨前后基本保持稳定;未施用微生态制剂的虾池在强降雨后,水体的弧菌数升高,Simpson指数和McIntosh指数显著降低(P<0.05),水体和底泥微生物群落对碳源的利用率变化明显。研究结果表明,与施用微生态制剂的虾池相比较,未施用微生态制剂的虾池在强降雨后,水体及沉积物环境波动变化明显,强降雨对其水域环境产生很大的影响。因此建议在对虾养殖过程中定期施用微生态制剂,并针对恶劣天气采取有效措施,以稳定虾池水体及沉积物的微生物生态。

珠江三角洲低盐度虾池秋冬季浮游微藻群落结构特征的研究

2007年9月—2008年1月,对广东省珠海市斗门区4口凡纳滨对虾低养殖池塘水体浮游微藻进行定期连续采样,分析了群落的结构特征。结果表明,共检出浮游微藻113种,其中绿藻55种,蓝藻21种,硅藻和裸藻各15种,隐藻和甲藻各3种,金藻1种。优势种有8种,主要为蓝藻门种类,有圆胞束球藻(Coelosphaerium naegelianum)、绿色颤藻(Oscillatoria chlorine)、假鱼腥藻(Pseudoanabaena sp.)、卷曲螺旋藻(Spirulina spirulinoides)、拟短形颤藻(Oscillatoria subbrevis)和粘连色球藻(Chroococcus cohaerens),其次还有硅藻门的角毛藻(Chaetoceros sp.)和新月菱形藻(Nitzschia closteriu)。养殖早期浮游微藻个体数量介于7.9×105～6.2×107ind·L-1之间,生物量0.05～2.9mg·L-1,多样性指数平均为2.02～2.68;养殖中后期浮游微藻个体数量介于37.2×107～2.1×109ind·L-1之间,生物量11.6～502.9mg·L-1,多样性指数平均为2.39～3.36。浮游藻类的种类、个体数量、生物量及多样性指数均表现为养殖前期低后期高的变化规律。

敌百虫对虾池生物的毒性

研究了敌百虫对青岛大扁藻、三角褐指藻、球等鞭金藻和海洋原甲藻等4种海洋微藻及天津厚蟹、脊尾白虾和克氏纺锤水蚤等3种野生甲壳类 ,以及中国对虾、缢蛏和台湾红罗非鱼等3种养殖生物的毒性。研究结果表明 :敌百虫在低浓度下对海洋微藻的生长没有明显影响 ,在一定浓度范围内甚至有促进作用 ,但超过一定浓度范围能完全抑制海洋微藻的生长。各种海洋微藻对敌百虫的敏感性不同。对3种野生甲壳类的半致死浓度分别为 :天津厚蟹LTD50(96h)为1.25×10-6;脊尾白虾LTD50(12h)为0.05×10-6;克氏纺锤水蚤LTD50 (48h)为0.063×10-6。敌百虫对3种养殖生物的半致死浓度分别为 :中国对虾LTD50(48h)为0.060×10-6;缢蛏LTD50(72h)为18.79×10-6;台湾红罗非鱼LTD50(72h)为36.35×10-6。文中还对敌百虫作为对虾病毒病预防药物的价值进行了探讨。

对虾养殖池塘氮磷收支的实验研究

用六个面积２５ｍ２，不同对虾放养水平：５２０００、６００００、７５２００尾／ｈｍ２的池塘围隔进行了本实验研究。结果表明：实验中投放的饵料、肥料分别占氮总输入的４９．７％～５４．５％和４７．５％～５０．１％；占磷总输入的３０．０％～３４．７％和６５．１％～６９．９％。在支出项目中，收获对虾占氮磷总输入百分比分别为９．０６％～１１．５％和３．０２％～３．９４％。沉积氮磷量为其主要支出项目，分别占总输入的１９．４％～６４．６％和２１．７％～９５．９％。底泥中氮磷的渗漏只占其支出的很小部分，分别占其输入的５．０％和０．５％左右。

强天气干扰条件下粤西凡纳滨对虾养殖池塘细菌群落动态特征

于暴雨频发的华南雨季(2009年5月～8月)对粤西凡纳滨对虾(Litopenaeus vannamei)养殖池塘水体和底泥进行调查,研究在强天气干扰条件下养殖池塘细菌数量动态及多样性指数变化情况。结果发现,水体异养细菌在104～106cfu.mL-1间波动,弧菌(Vibrio sp.)数量在养殖初期高达105cfu.mL-1,虾池301#和404#自6月18日开始施用芽孢杆菌(Bacillus subtilis)等微生态制剂后,其弧菌数量维持在104cfu.mL-1以下,403#和305#波动较大且多次超过105cfu.mL-1;4口虾池水体弧菌与异养细菌的数量比值在养殖初期均超过20%,之后301#和404#保持在12%以下,403#和305#在养殖后期分别达到21%和33%。底泥异养细菌先升高后稳定,弧菌数量除305#较稳定外,其他虾池波动较大(103～107cfu.g-1)。施用微生态制剂池塘301#和404#水体微生物群落多样性较前期降低,305#和403#较前期升高;底泥微生物群落多样性则呈现相同的变化规律,群落的丰富度、常见种的优势度和群落均度较前期有所降低。结果表明,施用微生态制剂的虾池可在气候多变的情况下保持养殖水体细菌群落的相对稳定,抑制弧菌滋生,降低微生态环境风险。

紫外诱变选育高活性蛋白酶枯草芽孢杆菌及其降解饲料能力评价

以凡纳滨对虾(Litopenaeus vannamei)养殖池塘底泥中分离的枯草芽孢杆菌(Bacillus subtilis)BC2为出发菌株,利用紫外诱变的方法培育蛋白酶活性高的枯草芽孢杆菌菌株,并评价其降解饲料的能力。结果表明:(1)经6次紫外诱变,突变菌株B38的透明圈直径(H)与菌落直径(C)之比(H/C值)达到6.42,提高了2.13倍;(2)福林酚法测得B38的蛋白酶活性为86.82 U/m L,是出发菌株BC2的3.14倍,但紫外诱变对B38纤维素酶活性影响不显著;(3)连续传代培养10代后发现B38产蛋白酶和纤维素酶能力保持稳定,证明诱变菌株具有较好的遗传稳定性;(4)利用凯氏定氮法评价B38降解饲料蛋白的能力,发现与BC2相比,B38降解饲料中可溶性蛋白的能力提高了2.57倍,而降解不溶性蛋白的能力变化不大。本研究诱变选育的枯草芽孢杆菌B38为开发优良的水产微生态制剂产品提供了重要的前提和基础。

中国对虾养成期间虾池水体和底质中细菌含量的变化

中国对虾养成期间虾池水体和底质中细菌含量的变化高尚德，陈旭仁，吴以平（青岛海洋大学，２６６００３）（青岛教育学院，２６６００１）关键词养虾池，细菌数量，变化ＶＡＲＩＡＴＩＯＮＯＦＴＯＴＡＬＢＡＣＴＥＲＩＡＮＵＭＢＥＲＩＮＳＨＲＩＭＰＰＯＮＤＷＡＴＥＲ...

虾池底质中NH_4^+-N、S^(2-)和异养细菌含量的变化及其相关性研究

随着养殖进程，底质中NH＋4-N、S2-和异养细菌的含量一直呈升高之势，其变化主要受控于底质中有机质含量的多寡，水温只是其影响因素之一。虾池底质中NH＋4-N、S2-和异养细菌的含量分布：沟泥＞滩泥＞池水，异养细菌和NH＋4-N、S2-含量呈正相关。文中对改善虾池底质环境，降低底质中NH＋4N。