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1.
对2002年和2003年的6~7月先后4次从朝鲜某滩涂养殖场引进的规格为8.3~12.5 g泥螺1 299 kg,以及采集自江苏启东当地自然海区规格为3.3~2.7 g的优质泥螺675 kg,进行亲贝育肥蓄养、人工催产、杂交繁育、浮游幼虫培育、附苗和利用土池进行稚贝大规模苗种中间培育试验。2年间除受灾损失稚贝1.045亿粒外,共对5.555亿粒经中间培育的幼贝进行滩涂围网及池塘养殖。至2003年10月31日,共捕获规格为6.3~7.1 g的商品螺1 147 t,,产值931.7万元,经济社会效益显著,是适宜在江苏沿海滩涂作为产业化规模贝类增养殖的优良品种,此技术在国内尚未开展。  相似文献   

2.
大獭蛤苗种池塘中间培育试验   总被引:2,自引:0,他引:2       下载免费PDF全文
2002年9月至2003年4月,在广西海洋研究所古城基地进行大獭蛤(LutmriamaximaJonas)苗种池塘中间培育试验。试验在铺沙的池塘里进行,放养的大獭蛤苗种规格为壳长0.2~0.8mm,大獭蛤稚贝饵料为施肥繁殖的浮游藻类,以大部分大獭蛤稚贝壳长达到2cm为出苗标准。结果表明,在水温为20~30℃、盐度为zo%。以上,放苗量为375万粒/公顷的条件下,大獭蛤稚贝经过45~60d即可以培育成壳长为2cm左右的大规格苗种。  相似文献   

3.
蔡德建  蒋艳  杨家林  彭慧婧  邹杰 《广西科学》2010,17(3):263-266,270
分别于2008年月12月至2009年3月和2009年5月至8月,2次在北海市乔港镇沿岸浅海进行大獭蛤(Lutraria maxima Jonas)人工苗种自然海区沉箱式中间培育试验。试验培育工具为长方形聚乙烯水果框,规格为长×宽×高=50cm×35cm×15cm,放苗前框内装满中沙。试验用大獭蛤苗种规格为壳长0.2~0.5cm。分别经过2次75d和45d的中间培育,大獭蛤人工苗种增长至出苗规格2.5~3.5cm,成活率分别为42.56%、41.13%。在海水温度25.0~31.5℃和1000粒/筐养殖密度下,大獭蛤人工苗种的浅海沉箱中间培育生长速度快,成活率高,苗种活力强,养殖成活率高。  相似文献   

4.
方格星虫苗种池塘中间培育试验研究   总被引:6,自引:0,他引:6  
蒋艳  蔡德建  邹杰  彭慧婧 《广西科学》2010,17(2):175-177
2008年8月19日至2008年10月22日在广西海洋研究所进行方格星虫(Sipunculus nudusLinnaeus)中间培育阶段苗种的生长及成活率的影响试验。试验共设3种不同的池塘底质,分别是海泥沙底质(1#)、中细河沙底质(2#)和中细河沙加配合饲料底质(3#),每口池塘面积0.2hm2,平均播苗密度为每公顷600万条。试验结果表明,中细河沙加饲料底质(3#)的池塘中培苗种生长速度最快,成活率最高,出苗数量最多,而中细河沙底质(2#)池塘的中培苗种次之,海泥沙底质(1#)池塘的中培苗种相对较差。1#、2#、3#池塘方格星虫苗种成活率分别为56.3%,78.%,80.2%,出苗数量分别为67.6万条、93.6万条、96.2万条。铺设适宜底质,投喂适量人工饵料,是提高方格星虫池塘中间培育技术的重要因素。  相似文献   

5.
曼氏无针乌贼胚胎发育与人工育苗技术的研究   总被引:7,自引:0,他引:7  
2003年以来,通过对乌贼人工繁殖生物学的研究,解决了乌贼胚胎发育、苗种繁育、成体快速养殖和当年生乌贼秋季育苗的关键技术,以期为乌贼的产业化发展及舟山渔场渔业资源的修复提供技术支撑.2006年利用乌贼仔三代和野生受精卵共6 810粒;孵出稚乌贼5 855头,孵化率为86.0%;获胴长20 mm的幼乌贼4 182头,培育成活率为71.4%;获胴长92~130 mm,体质量106~219 g的乌贼2 885头,养殖成活率为69.0%;通过乌贼的快速养殖与生殖调控,1 000头当年生乌贼秋季产卵151.6 kg,合97.02万粒.  相似文献   

6.
白蝶贝是世界上最大型的珍珠母贝,平均体长约20厘米,最大达30多厘米,可插1—2厘米的珠核,是培育粒大质优珍珠的好品种。但白蝶贝是热带深水品种,在我国海南岛,澳洲西北部到苏绿群岛、所罗门群岛到马来半岛之间均有发现,一般生长在15—30米水深的海区,采捕困难。由于没有解决人工育苗问题,目前国内外都只能用个体较白蝶贝小一半以上  相似文献   

7.
西施舌人工育苗及稚贝培育技术的研究   总被引:21,自引:0,他引:21  
选择野生 3龄西施舌 ,采取人工育肥、刺激产卵、选优培育、盘架式立体采苗、盘架式立体培育稚贝等技术工艺 ,培育出体长 3 .1~ 7.2mm幼贝 2 0 0 .9× 1 0 4粒 ,平均 3 .5 45× 1 0 4粒 /m2 .2 0 0 0年 9月2 6日 ,在陆上高位池 ,蓄养平均体长 9.8mm ,平均体重 0 .2 g的幼贝 2 0 .6× 1 0 4粒 ,以单细胞藻类为饵料 ,2 0 0 1年 7月 1日培育成功 ,平均体长 3 9.0 5mm ,平均体重 9.87g的 1龄西施舌幼贝 3 .1 0 5× 1 0 4粒 ,成活率为1 5 .0 7% .  相似文献   

8.
1999年3月2日至5月12日在浙江省乐清市海天水产苗种场采用向亲虾体内注射免疫增强剂和给蚤Ⅱ期后的幼体投喂口服型免疫增强剂的技术措施,进行了中国对虾(Penaeuschinensis)高健康虾苗的培育.结果表明,在800m3育苗水体中被注射的758尾人工养殖的中国对虾亲虾(13~15cm)产卵2.2亿个,孵化出0.7~0.9cm无特殊病原体和高健康虾苗1.3亿尾.  相似文献   

9.
大獭蛤工厂化育苗技术研究   总被引:1,自引:1,他引:0  
于2002年秋季在广西海洋研究所古城育苗基地和海滨公园育苗场进行大獭蛤(Lutraria(Psammophila)mascima Jonas)工厂化育苗研究。在育苗过程中采用成串的塑料片作为稚贝附着基立体附苗,使单位水体出苗量得到极大的提高。大獭蛤壳顶后期浮游苗至稚贝平均变态率为23.5%,小苗(大于8×10^4粒/500g)的平均单位面积出苗量为5.16×10^4粒/米^2,大苗(小于或等于8×10^4粒/500g)的平均单位面积出苗量为1.42×10^4粒/米^2,平均单位面积出苗量为3.29×10^4粒/米^2。  相似文献   

10.
利用人工培育的亲鱼所获得的受精卵,孵化出仔鱼300万尾,在水温18-20℃,微充气的培育条件下,使用海水小球藻,轮虫,卤虫无节幼体和不同规格的微颗粒配合的饲料进行饲喂,经58d培育出平均全长2.3mm的苗种132万尾,育苗成活率高达64.1%,单位水体最主出苗最达1.33万尾/m^3,另外,还有1.3-1. 9cm的苗种68万尾。  相似文献   

11.
讨论了破除野生大豆休眠和缩短发芽期的方法,提高种子发芽率的整齐度,采用了多因子试验,发现用砂纸打磨后的野生大豆种子,发芽率可高达90%左右,有效地解决了野生大豆发芽期长,发芽不整齐和发芽率低的问题.  相似文献   

12.
Jackson MG  Carlson RW 《Nature》2011,476(7360):316-319
Large outpourings of basaltic lava have punctuated geological time, but the mechanisms responsible for the generation of such extraordinary volumes of melt are not well known. Recent geochemical evidence suggests that an early-formed reservoir may have survived in the Earth's mantle for about 4.5 billion years (ref. 2), and melts of this reservoir contributed to the flood basalt emplaced on Baffin Island about 60 million years ago. However, the volume of this ancient mantle domain and whether it has contributed to other flood basalts is not known. Here we show that basalts from the largest volcanic event in geologic history--the Ontong Java plateau--also exhibit the isotopic and trace element signatures proposed for the early-Earth reservoir. Together with the Ontong Java plateau, we suggest that six of the largest volcanic events that erupted in the past 250 million years derive from the oldest terrestrial mantle reservoir. The association of these large volcanic events with an ancient primitive mantle source suggests that its unique geochemical characteristics--it is both hotter (it has greater abundances of the radioactive heat-producing elements) and more fertile than depleted mantle reservoirs-may strongly affect the generation of flood basalts.  相似文献   

13.
The nuclear bulge is a region with a radius of about 200 parsecs around the centre of the Milky Way. It contains stars with ages ranging from a few million years to over a billion years, yet its star-formation history and the triggering process for star formation remain to be resolved. Recently, episodic star formation, powered by changes in the gas content, has been suggested. Classical Cepheid variable stars have pulsation periods that decrease with increasing age, so it is possible to probe the star-formation history on the basis of the distribution of their periods. Here we report the presence of three classical Cepheids in the nuclear bulge with pulsation periods of approximately 20?days, within 40 parsecs (projected distance) of the central black hole. No Cepheids with longer or shorter periods were found. We infer that there was a period about 25 million years ago, and possibly lasting until recently, in which star formation increased relative to the period of 30-70 million years ago.  相似文献   

14.
梁志辉  王志成  陈竟敏  杨家林 《广西科学》2009,16(2):203-205,214
为寻找出一条适合广西北海地区高产、稳产、高效益、可持续发展的大规格对虾养殖模式,通过凡纳滨对虾(Litopenaeus vanmamei)无公害健康养殖试验,获得了显著效果。养殖池1口,面积0.2hm^2,放养虾苗的体长0.8~1.0cm,共8万尾。经136d养殖,获对虾1403.7kg,平均7018.5kg/hm^2,规格37.4尾/kg,成活率65.6%。产值44918元,扣除生产成本25854元,获利19064元,平均每公顷获利95322元。  相似文献   

15.
Willbold M  Elliott T  Moorbath S 《Nature》2011,477(7363):195-198
Many precious, 'iron-loving' metals, such as gold, are surprisingly abundant in the accessible parts of the Earth, given the efficiency with which core formation should have removed them to the planet's deep interior. One explanation of their over-abundance is a 'late veneer'--a flux of meteorites added to the Earth after core formation as a 'terminal' bombardment that culminated in the cratering of the Moon. Some 3.8 billion-year-old rocks from Isua, Greenland, are derived from sources that retain an isotopic memory of events pre-dating this cataclysmic meteorite shower. These Isua samples thus provide a window on the composition of the Earth before such a late veneer and allow a direct test of its importance in modifying the composition of the planet. Using high-precision (less than 6 parts per million, 2 standard deviations) tungsten isotope analyses of these rocks, here we show that they have a isotopic tungsten ratio (182)W/(184)W that is significantly higher (about 13 parts per million) than modern terrestrial samples. This finding is in good agreement with the expected influence of a late veneer. We also show that alternative interpretations, such as partial remixing of a deep-mantle reservoir formed in the Hadean eon (more than four billion years ago) or core-mantle interaction, do not explain the W isotope data well. The decrease in mantle (182)W/(184)W occurs during the Archean eon (about four to three billion years ago), potentially on the same timescale as a notable decrease in (142)Nd/(144)Nd (refs 3 and 6). We speculate that both observations can be explained if late meteorite bombardment triggered the onset of the current style of mantle convection.  相似文献   

16.
Dwyer CA  Stevenson DJ  Nimmo F 《Nature》2011,479(7372):212-214
Lunar rocks contain a record of an ancient magnetic field that seems to have persisted for more than 400 million years and which has been attributed to a lunar dynamo. Models of conventional dynamos driven by thermal or compositional convection have had difficulty reproducing the existence and apparently long duration of the lunar dynamo. Here we investigate an alternative mechanism of dynamo generation: continuous mechanical stirring arising from the differential motion, due to Earth-driven precession of the lunar spin axis, between the solid silicate mantle and the liquid core beneath. We show that the fluid motions and the power required to drive a dynamo operating continuously for more than one billion years and generating a magnetic field that had an intensity of more than one microtesla 4.2 billion years ago are readily obtained by mechanical stirring. The magnetic field is predicted to decrease with time and to shut off naturally when the Moon recedes far enough from Earth that the dissipated power is insufficient to drive a dynamo; in our nominal model, this occurred at about 48 Earth radii (2.7 billion years ago). Thus, lunar palaeomagnetic measurements may be able to constrain the poorly known early orbital evolution of the Moon. This mechanism may also be applicable to dynamos in other bodies, such as large asteroids.  相似文献   

17.
Attrill MJ  Power M 《Nature》2002,417(6886):275-278
Understanding the fluctuations in marine fish stocks is important for the management of fisheries, and attempts have been made to demonstrate links with oceanographic and climatic variability, including the North Atlantic Oscillation (NAO). The NAO has been correlated with a range of long-term ecological measures, including certain fish stocks. Such environmental influences are most likely to affect susceptible juveniles during estuarine residency, as estuaries are critical juvenile nursery or over-wintering habitats. Here we show that, during a 16-year period, climatic forcing (by means of the NAO) is consistently the most important parameter explaining variation in assemblage composition, abundance and growth of juvenile marine fish during estuarine residency. A possible mechanism for the effect of the NAO is a temperature differential between estuarine and marine waters that allows fish to facultatively exploit optimal thermal habitats. The connection has potentially important implications for the size and numbers of individuals recruited to the fishery, for understanding and predicting the composition of juvenile fish stocks using estuaries, and for the appropriate conservation of estuarine systems in relation to fish stocks.  相似文献   

18.
摘要: 金黄地鼠( Golden hamster; Mesocricetus auratus) 又称叙利亚地鼠,金黄色,成年个体体质量120-150 g,染色体 22 对。目前世界各国饲养的不同品系的金黄地鼠,都是1930 年在叙利亚发现的同胞后代,由于同一祖先,遗传学上血缘相近。金黄地鼠被广泛用于微生物学,肿瘤学,内分泌学,组织移植等的研究,此外还被大量用于制造乙型脑炎疫苗和狂犬疫苗。成都公司长期使用金黄地鼠制造乙型脑炎减毒活疫苗,本公司2003 年底建立SPF 金黄地鼠核心种群, 2004 年3 月建立规模化生产种群, 13 年来累计生产SPF 金黄地鼠180 万只,供应乙脑减毒活疫苗生产150 万只,累计生产乙型脑炎减毒活疫苗2. 3 亿人份,创造产值21 亿元人民币,其中乙脑疫苗出口创汇9 000 万美元。为了长期保持SPF 金黄地鼠种群遗传稳定性和质量稳定性,我们建立了一整套标准化的饲养管理制度和质量控制体系, 10 多年来,无论是公司自检,还是送中检院国家专业实验室检测或是送国外专业实验室检测,均未检测出需要排除的病原微生物和寄生虫, 2013 年我公司的乙脑减毒活疫苗制品成功通过WHO 预认证,作为关键原材料的SPF 金黄地鼠质量也得到了WHO 检查官的认可。  相似文献   

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