排序方式： 共有16条查询结果，搜索用时 125 毫秒
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通过亲贝强化营养和升温促熟培育,提早栉江珧人工育苗时间;合理控制幼虫密度,前期4~5个/mL,后期2~3个/mL,严把饵料质量关,投喂新鲜无污染的饵料,科学换水与充气,及时分级筛选等系列技术措施,克服栉江珧育苗中易发生幼虫粘连的技术难题,使育苗生产顺利进行;开展了多种附着基投放的采苗方法试验,选出了铺砂浮动网箱采苗和网袋装网片附着基和细砂吊在池中采苗2种比较理想的采苗方法,提高稚贝的附着变态率,其附着变态率达30%以上,促进稚贝的生长和成活,在1 000 m3水体中育出2 mm以上的稚贝1.096亿粒。 相似文献
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基于对水稻Jensen模型中敏感指数在全生育期变化规律的认识,以生长曲线函数建立了水稻敏感指数累积函数,分析了其特征,从而解决了不同长时段敏感指数转换计算问题。较全面地揭示了水稻水分生产函数及其敏感指数累积函数中主要参数随气象条件及土壤因子变化的规律。通过参照作物需水量及其频率以及不同地区土壤有效含水量为媒介,建立了对水分敏感指标在不同水文年份 (时间)和不同地区 (空间)进行预报的数学模型,据此提出了水稻水分生产函数在时、空两方面插补、延长、移用与扩展的理论与方法。借助于参照作物需水量等值线图及土壤分布图,探讨了绘制水分生产函数及其主要参数等值线图的原理和方法。 相似文献
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1974—1985年在烟台市、荣成和长岛县进行了自然海区采苗的试验研究。研究结果表明,采苗袋(笼)是较好的扇贝自然海区采苗器。 自然海区采苗技术的关键是:采苗袋网目在1.5毫米左右,内放少量网片作为稚贝附着基;海区透明度大;适时预报投放采苗器时间;掌握适宜的采苗水层。 该项技术经济效益显著。 相似文献
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P. Redfearn 《新西兰海洋与淡水研究杂志》2013,47(3-4):241-252
The larval shells of Paphies ventricosa, reared to settlement in the hatchery, are similar in longitudinal profile to shells of some other mactracean larvae; the umbo‐stage larval shells are nearly round with the anterior margin less broadly curved than the posterior margin, the anterior end is longer than the posterior end, and the umbo is broadly rounded. Straight‐hinge larvae had total lengths up to 149 μm, and total heights up to 126 μm, and umbo larvae had total lengths up to 320 μm, and total heights up to 282 μm. The larvae settled in about 22 days at a size of about 270 μm. The larval hinge structure bears some similarities to those of other mactracean larvae. 相似文献
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Effects of Soft Corals on Scleractinian Coral Recruitment. II: Allelopathy, Spat Survivorship and Reef Community Structure 总被引：1，自引：0，他引：1
Abstract. Two field experiments were performed on the Great Barrier Reef, Australia, at Orpheus Island and Lizard Island, respectively, to investigate the effects of allelopathic soft corals on survivorship and community structure of scleractinian coral spat. Ceramic tiles were placed around the allelopathic soft corals Sinularia flexibilis (Quoy & Gaimard 1833) and Sarcophyton glaucum (Quoy & Gaimard 1833), and controls. One control consisted of settlement plates surrounding a scleractinian coral (non‐allelopathic planktivore); another control had no adult soft or scleractinian coral present. The experimental soft corals affected the recruitment of various taxonomic groups of coral spat differentially, as evidenced by the diversity of coral spat settling in treatments and controls. At Orpheus Island (O.I., n = 1038 spat) and Lizard Island (L.I., n = 7032 spat), there were significant differences between recruitment success of the two dominant coral taxa, Pocilloporidae (O.I., 61.4 %; L.I., 20.5 %) and Acroporidae (O.I., 33.7 %; L.I., 53 %). Settlement plates exposed to Sinularia flexibilis at either site had the lowest proportion of acroporid recruits. Diversity indices (Shannon‐Wiener Indices) varied significantly between treatments at both Orpheus and Lizard Islands. This appears to be due to selective inhibition of acroporid spat by Sinularia flexibilis at both sites. Growth of coral spat was higher on settlement plates in the presence of Sarcophyton at Lizard Island. Settlement of most associated epibiota was generally inhibited under these conditions. Coral spat survivorship was highest in the presence of Sinularia at Orpheus Island; at Lizard Island, this was the case with the Sarcophyton treatment. Higher survivorship, and in some cases growth, of coral spat near soft corals was apparently due to reduced competition for space between spat and associated epibiota. This hypothesis is supported by the results of a sister experiment where a coating of Sinularia flexibilis extract on settlement tiles significantly decreased fouling by sessile epibiota. Soft corals have an allelopathic effect on recruitment and early development of scleractinian corals and, consequently, on early coral reef community succession. 相似文献
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基于GIS的青藏高原人口统计数据空间化 总被引：93，自引：6，他引：87
根据2000年第5次全国人口普查数据分析,西藏、青海2省区各市县平均人口密度与海拔高度、土地利用、主要道路有较强的相关关系,河流水系对居民点分布的影响较为明显,而居民点是人口分布的重要指示因子。以GIS软件为工具,通过较为客观的方式赋予各影响因子人口分布影响权重,运用多源数据融合技术进行了人口统计数据的空间化。结果显示,通过数据融合产生的人口密度与各市县实际人口密度的相关系数大于0.80,与试验区各乡镇的实际人口密度的相关系数大于0.75。最终生成的栅格人口密度数据既与各市县统计型人口数据保持一致,又反映了各市县内部人口分布的空间变化。 相似文献
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为提高单体“海大1号”长牡蛎(Crassostrea gigas)的培育效率,本研究以3种培育模式(下降流、上升流和静水)、6个水流量梯度(20、35、50、65、80和95 mL/s)和6个培育密度梯度(2.5、5、7.5、10、12.5和15个/mL)对单体“海大1号”长牡蛎苗种中间培育生长情况进行了研究。研究表明,单体“海大1号”长牡蛎苗种中间培育时,上升流和下降流均比静水培育效果好,培育前5天采用下降流、第6~29天采用上升流时,稚贝生长快、死亡率低;水流量小于65 mL/s时,随水流量的增加,稚贝生长加快,死亡率降低,水流量在65~80 mL/s时,单体牡蛎稚贝生长存活最优,第29天时最大壳高达(1534.81±65.23)μm。单体“海大1号”长牡蛎稚贝苗种中间培育时,随着培育密度的增大,挤迫效应逐渐显现,密度为7.5个/mL时,死亡率相对较低,且稚贝生长速度快,在第29天时稚贝壳高最大可达(1520.63±51.72)μm。基于以上研究结果,建议在规模化单体“海大1号”长牡蛎稚贝中间培育时,采用上升流和下降流相结合的流水培育方式,适当增加水流量,及时疏散密度。本研究优化了单体“海大1号”长牡蛎室内培育模式,为单体牡蛎规模化培育提供了参考方法和理论依据。 相似文献
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肠道细菌对厚壳贻贝稚贝附着的作用研究 总被引：1，自引：0，他引：1
为探讨肠道细菌形成的微生物被膜对贝类附着的作用,从厚壳贻贝(Mytilus coruscus)成体肠道中分离10株肠道细菌,调查厚壳贻贝肠道细菌形成微生物被膜特性,分析微生物被膜密度、细菌种属与厚壳贻贝稚贝附着之间的相互关系。所有肠道细菌均可有效促进稚贝附着。其中,Paracoccus sp.1微生物被膜诱导的稚贝附着率最高(61%),且微生物被膜膜厚较厚,细菌分布较密集;仅5株肠道细菌Roseovarius sp.1、Winogradskyella sp.1、Tenacibaculum sp.4、Bacillus sp.5和Nonlabens sp.1的被膜密度与附着显著相关(P0.05)。系统发育分析发现肠道细菌诱导附着率与其种属无关。本研究表明源于厚壳贻贝成贝肠道细菌可以促进其稚贝的附着,说明肠道细菌对厚壳贻贝的生长发育具有一定的作用。本研究结果为深入探讨肠道细菌与厚壳贻贝相互作用和推动该种规模化养殖提供理论依据。 相似文献
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单体全三倍体太平洋牡蛎育苗技术的研究 总被引：2，自引：0，他引：2
本文利用四倍体太平洋牡蛎雄贝与二倍体雌贝杂交生产出的全三倍体牡蛎,幼虫经常规方法培育至60%出现眼点幼虫时,投放聚乙烯塑料纸、废旧筛绢网和聚乙烯波纹板作附着基,经过附着变态后,当达到2～3 mm时,可脱基生产单体牡蛎,也可中间培育至10 mm边脱基边出售到养殖单位进行养殖,采用此法生产的单体牡蛎方法简便,成本低,脱基致残率极低,是一种生产单体牡蛎好方法之一.2005-2006年在50m3水体中生产单体牡蛎1000万粒 (1cm),单位水体出苗量为20万粒/m3. 相似文献