1.1 本规程涵盖了使用锥形拖网获取浮游动物群落定性样本的程序。网将收集大多数浮游动物，但有些形式会避开网。 1.2 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 3.1 这个 优势 使用锥形牵引网的方法如下: 3.1.1 它们相对便宜，在各种内陆、河口、沿海和海洋水域用途广泛。 3.1.2 它们可以在配备最少辅助设备的小型或大型动力船上使用。 3.1.3 当安装流量计时，它们可用于收集定性样品和半定量样品，当在环箍外部安装配对仪表以监测过滤效率时，甚至可以收集更好的样品。 3.2 这个 缺点 锥形牵引网的数量如下: 3.2.1 当配备流量计时，它们需要经常维护，包括校准和润滑（在某些类型中）。 3.2.2 它们只有在通过具有相当厚度的水流时才有效。它们不适合从较小或受限区域收集样本。 3.2.3 它们不适合在浅水中采集。 3.2.4 它们被草床、腔肠动物和丝状藻类堵塞。 3.2.5 当与流量计一起使用时，它们仅收集定性样品或半定量样品。 3.2.6 当使用水平拖带对离散深度进行采样时，如果不使用打开和关闭装置，样品在部署和回收期间可能会受到其他深度的污染。 3.3 有几个 特殊注意事项 使用锥形牵引网时应遵守这一点。他们是: 3.3.1 锥形拖网取样器设计为以小于3节的速度拖曳；然而，更大的渔网使用了更高的速度，同时捕获量也增加了。 2. 3.3.2 应使用直径为0.5 m或更大的锥形拖网，以减少生物体的躲避。 2. 3.3.3 应经常清洗网，并检查销孔、撕裂、网劣化和其他异常情况。 3.3.4 在储存前，应允许蚊帐在空气中和柔和光线下完全悬浮时干燥。 3.3.5 当在白天采集时，可能会降低每个样本的捕获量。这些在较大的浮游动物中尤其明显。 （A） Sage，L.E.，” 浮游动物 ，“英寸 采矿对水生群落影响的评估和预测方法: 回顾与分析 ，鱼类野生动物服务/生物服务办公室，第78卷，第30号，1978年4月，第55-65页。

1.1 This practice covers the procedure for obtaining qualitative samples of a zooplankton community by use of conical tow nets. Nets will collect most zooplankton, but some forms will avoid nets. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 3.1 The advantages of using conical tow nets are as follows: 3.1.1 They are relatively inexpensive and highly versatile in a variety of inland, estuarine, coastal, and marine waters. 3.1.2 They can be used from a small or large powered boat with a minimum of auxiliary equipment. 3.1.3 They can be used to collect qualitative samples and semiquantitative samples when fitted with a flowmeter and even better samples when fitted with a companion meter on the outside of the hoop to monitor filtering efficiency. 3.2 The disadvantages of conical tow nets are as follows: 3.2.1 When equipped with a flowmeter they require frequent maintenance including calibration and, in some types, lubrication. 3.2.2 They are effective only where drawn through a stream of water having considerable thickness. They are not suitable for collecting samples from a small or restricted region. 3.2.3 They are not suitable for collecting in very shallow water. 3.2.4 They are clogged by grass beds, coelenterates, and filamentous algae. 3.2.5 When used with a flowmeter, they collect only qualitative samples, or semiquantitative samples. 3.2.6 When sampling discrete depths using a horizontal tow, the sample can be contaminated from other depths during the deployment and retrieval of the samples if opening and closing devices are not used. 3.3 There are several special considerations that shall be observed when using conical tow nets. They are: 3.3.1 Conical tow net samplers are designed to be towed at speeds less than three knots; however, greater speeds have been used for the larger nets with a concomitant increase in capture. 2 3.3.2 A conical tow net 0.5 m in diameter or larger shall be used to reduce avoidance by organisms. 2 3.3.3 The nets shall be washed frequently and inspected for pin-size holes, tears, net deterioration, and other anomalies. 3.3.4 Nets should be allowed to dry while suspended full length in air and in subdued light prior to storage. 3.3.5 Lower catches per sample may result when collections are made during the day. These are particularly noted in the larger zooplanktons. (A) Sage, L. E., “ Zooplankton ,” In Methods for the Assessment and Prediction of Mineral Mining Impacts on Aquatic Communities: A Review and Analysis , Fish Wildlife Service/Office of Biological Services, Vol 78, No. 30, April 1978, pp. 55–65.