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41.
Whale sharks, a global migratory species, are often reported entangled in fishing nets in coastal areas of China. The effectiveness of conservation measures has been constrained by very limited knowledge on their movements and preferred habitats in the coastal areas of China. For the first time, we tracked the movements of 2 whale sharks by satellite telemetry in Mainland China. The tracking results of 1 whale shark revealed that it travelled in the South China Sea in a south-eastern direction, parallel to the eastern coast of Vietnam. Total distance travelled was 1018 km, in approximately 74 days, with a mean speed of 14 km per day. It appeared to head towards the cool upwelling zones in southern Vietnam at the time of the tag's detachment. In our study, it was observed that this whale shark was a surface dweller and spent approximately 45% of its time above 10 m water depth and 90% of its time above 50 m depth. It also tended to stay in water temperatures between 27 and 30 °C, and was rarely recorded in water below 20 °C. This preliminary study indicates the importance of shallow waters as the foraging habitat for whale sharks, and has implications for their management and conservation. 相似文献
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43.
文章根据辽宁省5年来森林资源变档工作实践,论述森林资源变档工作,管理模式、内容、在林业建设中的作用、及存在的问题、提出相应对筞。森林资源变档以小班为单位,通过科学技术手段,实现了每年更新一次森林资源数据,实现了从静态管理到动态管理转变。为各级政府、林业主管部门、及森林经营单位制定林业方针政策,编制林业规划设计、指导林业生产提供科学基础数据,为调整林业政策、提高林业管理水平,提供最新的科学依据。 相似文献
44.
针对《行政处罚法》颁布实施前后,水行政主管部门应如何根据自身实践做好相关的各项工作,提出了个人见解,以规范水土保持行政处罚行为,力求在水土保持行政执法中做到有理、有据、合法、避免执法违法现象存在,确保水土保持行政执法不断深入。 相似文献
45.
JOHN P. HOOLIHAN JIANGANG LUO C. P. GOODYEAR ERIC S. ORBESEN ERIC D. PRINCE 《Fisheries Oceanography》2011,20(3):192-205
Vertical habitat use of sailfish (Istiophorus platypterus) was evaluated using pop‐up satellite archival tag data from the eastern tropical Atlantic, western North Atlantic, and eastern tropical Pacific. Data included Argos transmitted depth, temperature, and light level frequency histograms binned at 1–8‐h intervals, and four recovered pop‐up satellite archival tags that provided high resolution archival data recorded at 30‐s intervals. We tabulated the proportions of time spent within each degree of water temperature relative to the surface temperature (Delta T) and proportions of time at temperature, as these are major input variables for habitat standardization models used in stock assessment procedures. Frequency distributions were calculated for daylight, darkness, and twilight for each of the three regions and for all regions combined. Vertical habitat envelopes indicated greater use of deeper strata in the western North Atlantic, compared to the hypoxia‐based habitat compressed regions of the eastern Atlantic and Pacific. However, there were no significant differences in Delta T distributions when comparing the three regions, affirming this metric for its application in habitat standardization models. 相似文献
46.
Satellite telemetry is used routinely to collect and transmit movement, behaviour and environmental data from free‐ranging animals. Satellite tags (hereafter SATs) are essential for collecting in situ data from animals where manual retrieval of a data logger is impossible. The collected data is fundamental for scientific and many management applications. However, the amount of data a SAT can transmit is limited by its battery life, transmission opportunities, bandwidth and satellite coverage. When designing a SAT study, these factors should be taken into account to ensure that limited transmissions are utilized as effectively as possible. In this paper we present a theoretical discussion of the factors that influence the data transmission and present tools for designing effective SAT studies. We calculate the optimal sampling period for the tag given its expected lifetime and regional variation in satellite coverage. Taking these factors into account allows prediction of the expected number of tags required to meet targets for a deployment. These methods are applied to a case study of a highly migratory pelagic fish tagged with popup archival satellite tags (PSATs). Our findings will be useful for SAT study design in general and demonstrate an approach which can reduce the ad hoc nature of SAT deployments. 相似文献
47.
旋转导向管新型喷动床空气动力学特性研究 总被引:2,自引:2,他引:0
为放大常规喷动床,提出了“旋转导向管喷动床”新概念,设计并安装了两种旋转导向管喷动床。以小麦为原料,测定了旋转导向管新型喷动床的空气动力学特性,包括不同导向管在相同导喷距下风速与床层压降关系、导喷距对风速与床层压降关系的影响和旋转导向管喷动床的循环量等性能。研究结果表明:采用旋转导向管后物料可洒布在整个床层截面上,因此可放大喷动床的直径;在喷动发生后,旋转导向管新型喷动床的床层压降与普通导向管喷动床的床层压降差异较小;导喷距影响最大床层压降,采用调节导向管安装高度的方法,可不考虑最大喷动压强,而根据正常喷动时的压降选用风机。 相似文献
48.
抗旱造林新技术在甜柿建园中的应用 总被引:2,自引:0,他引:2
在甜柿建园中,通过ABT生根粉,SAP高效抗旱保水剂和地膜覆盖技术的应用.可显著提高造林成活率和苗木生长量。通过试验研究.总结出组装配套技术.造林成活率达到98%以上.值得大力推广。 相似文献
49.
文红梅 《四川畜牧兽医学院学报》2006,4(1):99-102
在我党历史上先后有过3次大的经验总结,促进了党的自身建设及理论上的成熟。第一次总结为中国民主革命的胜利奠定了基础;第二次总结找到了有中国特色的社会主义建设道路;第三次总结把党对历史经验的总结提高到一个崭新的高度,为全面建设小康社会提供了有力的保证。 相似文献
50.
【目的】标定新疆地区粉土离散元仿真模型,量化分析农业机械触土部件与土壤的相互作用。【方法】采用EDEM离散元仿真软件,运用斜坡试验标定土壤与触土材料(65 Mn)之间的接触参数,堆积角试验标定土壤与土壤之间的接触参数,以斜坡滚动距离为优化目标进行回归分析。【结果】土壤与65 Mn之间离散元模型参数的一种优化组合为恢复系数0.51,静摩擦系数0.56,动摩擦系数0.08,JKR表面能4.12;以堆积角为优化目标,土壤之间离散元模型参数的一种优化组合为恢复系数0.57,静摩擦系数0.65,动摩擦系数0.23,JKR表面能4.49。滚动距离和堆积角的误差分别为6.05%、1.28%。【结论】在建立的仿真模型条件下,在8、9、10 km/h作业速度下,犁体仿真试验与实际试验的工作阻力相对误差为5.69%、5.95%、6.49%,建立的模型真实可靠。 相似文献