993 resultados para 1995_03161606 TM-7 4500405
Resumo:
This report comprises a summary of parasitic copepods from fishes in Ceylon, as isolated from the branchial material of fishes belonging to previous collections. Seven copepod species are described in detail, as well as one species of Branchiura and one species of Isopoda. Caution is advocated to avoid further introductions via parasite-infested fishes, since only four of the above species are endemic.
Resumo:
Using a magneto-optical (MO) technique, magnetic field distributions have been measured in a melt-textured YBa 2Cu 3O 7-x bulk superconductor, joined to form an artificial grain boundary (GB), in an external magnetic field perpendicular to the sample surface. The magnetic field at a weak section of the GB shows different values between the field increasing up to 150mT and decreasing down to 0T after zero-field-cooling. Namely, the magnetic field in increasing field is higher than that in decreasing field, even in the same external field. This result supports a model in which such differences in magnetic field at the weak-link GB give rise to the hysteresis behavior in the field dependence of transport critical current density in polycrystalline samples. The field distributions across a well-joined region of the GB behave similarly to the adjoining bulk material and this result indicates the possibility of creating useful artifacts provided that the strongly coupled sections can be reproduced on a larger scale.
Resumo:
This report of the cruise along the Sofala Bank (Mozambique) describes the catch composition and catch distributions of the shallow water shrimp. Biological data are given for Penaeus indicus and Metapenaeus monoceros which represent 77% of the total catch.
Resumo:
Catch composition and bathymetric distribution of demersal fish caught along the coast of Mozambique between parallels 16 degree 20' and 19 degree 30' S at depths of 11 to 180 metres are given. The shrimp by-catch was also studied.
Resumo:
This report of the research cruise (7 to 23 June 1981) surveying pelagic marine resources of the Sofala Bank (Mozambique) describes the size composition, distribution, length-weight relationships and sex-ratio of the fish captured. Decapterus russellii, D. macrosoma, Selar crumenophthalmus and Rastrelliger kanagurta represented 21.7% of the total catch. The by-catch was also studied.
Resumo:
This report of the research cruise (21 July to 7 August, 1981) surveying pelagic marine resources of the Sofala Bank (Mozambique) describes size composition distribution, length-weight relationships and sex-ratio of the fish captured. Decapterus russellii, D. macrosoma, Selar crumenophthalmus and Rastrelliger kanagurta represented 21.7% of the total catch. The by-catch was also studied.
Resumo:
本文研究的开展主要源于国家海洋局海洋公益性行业科研专项经费项目“渤海典型区域的海洋多过程数据整合研究”课题支撑。在湿地日益退化丧失的全球背景下,本文选择沉积年代较轻、生态环境比较脆弱,且当前人类活动不断加剧的现代黄河三角洲为研究区,采用1999、2001、2004和2008年的Landsat5 TM遥感影像,选择丹顶鹤和黑嘴鸥为指示物种,结合野外实地调查和历史数据资料的整理和分析,以及黄河三角洲自然保护区对鸟类的监测记录结果,开展现代黄河三角洲湿地景观变化及其对水禽生境的影响研究。 论文的主要研究结果如下: 1、建立了服务于黄河三角洲湿地水禽生境保护的湿地景观分类体系 在系统分析研究区域湿地水禽生活习性和生态分布特征的基础上,从鸟类生境选择的概念出发,建立了服务于黄河三角洲湿地水禽生境保护的湿地景观分类体系。该分类体系一共分为4级,其中,第三级分类系统下天然湿地的划分是从鸟类选择的“大生境”角度出发,即根据区域地表类型,进一步将海洋/海岸湿地和内陆三角洲湿地划分成浅海水域、潮间淤泥滩、潮沟、河口水域、潮间盐沼、河流湿地和沼泽湿地7类。而第四级分类系统下天然湿地的划分则是从鸟类选择的“小生境”(即对水、食物、隐蔽物、干扰等的需求)角度出发,并按照水文和典型植被类型,进一步将天然湿地的三级类型划分为碱蓬沼泽、芦苇沼泽、柽柳灌丛沼泽等33类。 2、系统研究了现代黄河三角洲湿地景观格局的动态变化和影响因素 根据景观生态学理论,选取用于分析的景观格局指数,并从湿地景观类型的组成特征变化、面积变化、形状特征变化、空间配置特征变化四个方面分析在黄河断流前到其恢复正常行水至今的时间里三角洲湿地景观格局的动态变化,研究结果表明:在1999~2008年的9年间,天然湿地构成了现代黄河三角洲景观的主体,约占研究区域景观总面积的65%~75%,决定了该地区湿地的主要结构和功能。但随着人类对土地资源利用方式的不断改变和强度的提高,天然湿地景观呈萎缩退化趋势,9年内共减少338.44 km2,约占研究区景观总面积的8.90%。与此同时,盐田、养殖池塘等人工湿地和耕地等非湿地面积不断扩张,人工湿地面积增加量约为242.08km2,约占研究区景观总面积的6.37%,非湿地面积增加量约为96.36 km2,约占研究区景观总面积的2.53%。从一些重要的景观指数的计算结果来看,研究区域整体景观斑块数量呈增加趋势,平均斑块大小随之减小,景观边界密度大小、聚集度指数也呈下降趋势,表明从1999到2008年研究区域整体景观被边界分割的程度加深,整体景观中的斑块在空间分布上隔离程度加重,开始由大片连续分布向小块离散分布转变,景观的破碎化程度加重。 湿地景观格局变化的驱动机制分析表明,影响研究区湿地景观变化的主要因素包括三个方面,即:黄河水沙条件的驱动力、湿地自身演替驱动力和人为驱动力。在1999~2008年的9年间,黄河虽然恢复正常行水,不再断流,但入海泥沙量的明显减少使得除现行河口处沙嘴继续向海缓慢延伸外,黄河三角洲总体上处于侵蚀状态。湿地自身的演替主要体现在湿地由裸露淤泥质滩涂向发育典型湿地植物群落的顺向演替,以及发育有典型湿地植物群落的湿地向裸露淤泥质滩涂逆向演替两个方面。在1999~2008年间9年里,湿地顺向发育演替面积约130.64 km2,而逆向发育演替面积约为99.51 km2。人类活动一直以来都是影响黄河三角洲湿地景观变化不可忽视的营造力。大规模的滩涂围垦和养殖、农业用地的不断开垦和扩张,以及密集的油田开发活动不仅缩减了原本生长着芦苇茅草等植物的天然湿地资源,而且加重了三角洲湿地景观的破碎程度。 3、在整个研究区域尺度上深刻分析了丹顶鹤和黑嘴鸥潜在生境的适宜性 根据黄河三角洲自然保护区关于鸟类的监测记录资料,在深入分析湿地水禽生活习性和分布特征的基础上,选择丹顶鹤和黑嘴鸥为指示物种,从鸟类生境选择自身的特征出发,确定地表类型、水、食物、隐蔽物和干扰为影响两种鸟类类群进行生境选择的因素,并构建生境适宜性评价模型,在整个研究区域尺度上对两种鸟类类群的潜在生境进行适宜性评价和动态变化分析。研究结果表明,在不考虑居民地、油田作业用地和道路等干扰因子对生境产生的破碎化效应影响时,适宜丹顶鹤和黑嘴鸥生存的生境类型在1999~2008年间占研究区整体景观总面积的比重均在30%以上,其中天然湿地约占适宜生境类型面积的95%,可利用的人工湿地比重极小,但呈缓慢增加趋势,且由于可利用的天然湿地生境类型的逐年减少使得适宜两种鸟类类群的生境类型总面积总体上呈萎缩趋势。在考虑居民地、油田作业用地和道路等干扰因子对生境产生的破碎化效应影响时,适宜丹顶鹤和黑嘴鸥生存的生境类型在1999~2008年间占研究区域整体景观总面积的百分比由之前接近40%下降到20%以下,面积减少量均在600 km2以上。 4、系统分析了研究区湿地景观变化对水禽生境的影响 从研究区湿地景观基质的面积变化、形状和空间邻接关系变化、破碎化等三个方面分析了研究区湿地景观变化对丹顶鹤和黑嘴鸥两种鸟类类群生境的影响,结果表明,湿地景观基质中天然湿地的变化与丹顶鹤、黑嘴鸥适宜生境的大小和空间分布密切相关。在1999~2008年间,随着天然湿地面积的减少,适宜以上两种鸟类类群的生境面积也随之减少,两者呈正相关关系;在1999~2008年间,研究区天然湿地和人工湿地景观基质整体的形状指数均在1.0附近,表明湿地景观基质整体上的边缘效应较小,但建设用地、农林用地等非湿地景观与丹顶鹤和黑嘴鸥适宜生境类型中的主导类型——潮间淤泥滩、潮间盐沼和沼泽湿地等三种景观类型的频繁邻接,对于保护两种鸟类类群十分不利,应积极采取相应的措施加强保护力度;在1999~2008年间,研究区景观整体,以及湿地景观基质结构的破碎化,导致鸟类可利用的天然湿地和人工湿地景观内部斑块之间的连接程度下降,从而使得丹顶鹤、黑嘴
Resumo:
The workshop titled, ICSF-BOBLME India (East Coast) Workshop on Implementing the FAO Voluntary Guidelines for Securing Sustainable Small-scale fisheries in the Context of Food Security and Poverty Eradication (SSF Guidelines) was organized by ICSFin collaboration with BOBLME project.The workshop was the third in a series of consultations held in 2015 across the globe to promote the ownership of the SSF Guidelines among different stakeholders. In the run –up to the workshop, ICSF, with support from BOBLME conducted six consultation meetings with fishworkers and fishworker organizations along the east coast of India in January and February 2015. One hundred participants from India’s eastern coastal states of West Bengal, Odisha, Andhra Pradesh, Tamil Nadu and Puducherry, including women fishworkers, representatives of fishworker organizations, representatives from Department of Fisheries and other concerned departments at state and central level, Multilateral agencies, Inter-governmental organizations, Research Institutions met at Chennai, 6-7 March, 2015. The workshop was structured to facilitate active interaction and discussion among participants, taking into account linguistic diversity and the contextual differences of the marine and inland sectors. This publication—the proceedings of the Chennai workshop—will be useful for fishworker organizations, researchers, policymakers, members of civil society and anyone interested in fisheries and livelihoods.
Resumo:
Multidirectional chromosome painting with probes derived from flow-sorted chromosomes of humans (Homo sapiens, HSA, 2n = 46) and galagos (Galago moholi, GMO, 2n = 38) allowed us to map evolutionarily conserved chromosomal segments among humans, galagos, a