Macrozooplankton from the southern North West shelf, Western Australia

The distribution and abundance of macrozooplankton on the southern North West Shelf of Western Australia was investigated over two consecutive summers (October to February) of 1997-1998 and 1998-1999, using submersible light traps. Sampling was conducted over a period of 10 days centred on successive new moons. Traps were deployed at the surface and at depth along one cross-shelf transect in the first summer, and along two cross-shelf transects and one long-shore transect in the second summer.At each station, a CTD equipped with a fluorometer was deployed within a few metres of the bottom concurrently with light trap sampling. Wind speed and wind direction were obtained from the weather station at Milyering.On retrieval, catches were immediately preserved in ethanol. In the laboratory, one sample of catches from each of the paired light traps was sorted into 14 broad taxonomic groups, distinguished with the unaided eye and counted.Vertical zooplankton hauls were to a maximum depth of 60m using a 0.5 m, WP-2 net of 73 µm mesh fitted with a flowmeter. Samples were filtered through a mesh dish and frozen.
This research was undertaken to describe the temporal and spatial distribution of macrozooplankton on the North West shelf, using submersible light traps. The relationship between observed distributions and environmental parameters was also investigated. The euphausiids, which are difficult to capture by other means were chosen for more detailed examination.

本研究于1997-1998年及1998-1999年两个连续夏季（10月至次年2月），采用水下光诱捕器（submersible light traps），对澳大利亚西部西北陆架南部的大型浮游动物（macrozooplankton）分布与丰度展开调查。采样以连续朔望月为中心，周期为10天。首个夏季，研究团队沿一条跨陆架断面，在表层及不同深度布设诱捕器；第二个夏季则沿两条跨陆架断面与一条沿岸断面布设诱捕器。在每个采样站位，研究人员同步在近底数米范围内部署搭载荧光计（fluorometer）的温盐深仪（CTD），并同步开展光诱捕采样。风速与风向数据取自Milyering气象站。诱捕器回收后，样品立即以乙醇固定。实验室阶段，研究人员将成对光诱捕器获取的每份捕捞样品通过肉眼分拣为14个宽泛分类类群并完成计数。
另采用搭载流量计（flowmeter）的0.5米口径、73微米网目WP-2型网（WP-2 net），在最大60米水深开展垂直浮游生物拖网采样，样品经滤皿过滤后冷冻保存。
本研究旨在借助水下光诱捕器描述西北陆架大型浮游动物的时空分布特征，同时探究其分布与环境参数之间的关联。针对其他采样方式难以捕获的磷虾类（euphausiids），本研究开展了更为细致的分析。