Status of fringing reefs in the Northumberland Islands, southern Great Barrier Reef

Fringing reefs surrounding islands within the Northumberland Islands group were surveyed in September 2000. The Northumberland Islands occupy a relatively large area (approx 9000 km²). In order to get good geographic coverage of reefs, a sub-sample of islands was targeted within three distinct zones at various distances from Broad Sound and the coast.The study zones were:1. near-shore islands immediately adjacent to the coast (within 3km, Temple Island group and West Hill Island)2. mid-shore islands located approximately midway between the coast and the outer limit of the Northumberland Islands (Knight Island, Curlew Island and Poynter Island)3. offshore islands on the seaward side of the Northumberland Islands group bordering the lagoon of the GBR (Prudhoe Island, Pine Peak Island and South Percy Island).Surveys used one or more of the following techniques to gain a broadscale overview of reef habitat around island perimeters and to identify areas of fringing reef that would be suitable for long-term monitoring:1. Broadscale surveys used manta tow or, if visibility was less than 6m, spot checks. For manta tow surveys, the variables recorded included crown-of-thorns starfish counts, estimates of live coral, dead coral and soft coral cover, and the number of bleached corals. During spot checks, observers recorded substrate type and associated benthic organisms, but did not estimate coral cover.2. Detailed surveys were carried out along a series of 50m transects at each reef. Benthic organisms occurring along the transects were recorded on video for later analysis. Fish were also identified along each transect, however fish abundance was not recorded. The objectives of this research were:1. to provide an assessment of the status of coral and reef fish communities around a variety of islands within the Northumberland Islands group.2. To provide an interpretation of those data in terms of:a) how the Northumberland Islands reef biota compare with reef assemblages in other regions within the GBRb) the comparative biological/ecological value of the Northumberland Island's reefs c) historical comparisons of reef status (where data is available) to indicate current reef trajectoriesd) options for long-term monitoring of these reefs.

2000年9月，研究人员对诺福克群岛（Northumberland Islands）群内岛屿周边的裙礁（fringing reefs）开展了调查。诺福克群岛总面积约9000平方千米，覆盖范围相对广阔。为实现礁区地理覆盖的全面性，研究团队在距布罗德桑德（Broad Sound）与海岸不同距离的三个独立区域内，选定了岛屿子样本开展调查。

本次研究的区域分为三类：
1. 近岸岛屿：紧邻海岸（3千米范围内），包括坦普尔群岛（Temple Island group）与西山岛（West Hill Island）；
2. 中岸岛屿：位于海岸与诺福克群岛外边界大致等距的区域，涵盖奈特岛（Knight Island）、杓鹬岛（Curlew Island）与波因特岛（Poynter Island）；
3. 离岸岛屿：位于诺福克群岛群向海一侧，毗邻大堡礁（Great Barrier Reef, GBR）潟湖，包括普鲁德霍岛（Prudhoe Island）、松峰岛（Pine Peak Island）与南珀西岛（South Percy Island）。

本次调查采用以下一种或多种技术，以全面获取岛屿周边礁生境的宏观概况，并筛选出适合长期监测的裙礁区域：
1. 宏观普查：采用蝠鲼拖曳调查（manta tow），若能见度低于6米，则采用定点检查（spot checks）。对于蝠鲼拖曳调查，记录的变量包括长棘海星（crown-of-thorns starfish）的种群数量、活珊瑚、死珊瑚与软珊瑚覆盖率的估算值，以及白化珊瑚的数量。在定点检查环节中，调查人员会记录底质类型与相关联的底栖生物，但不进行珊瑚覆盖率的估算。
2. 详细调查：在每个礁区沿一系列50米样带开展调查。样带沿线的底栖生物会被录制为视频，以供后续分析。同时会识别样带沿线的鱼类，但不记录鱼类的丰度。

本研究的目标如下：
1. 评估诺福克群岛群内各类岛屿周边的珊瑚与礁区鱼类群落的现状；
2. 基于采集的数据开展如下解读：
a) 诺福克群岛礁区生物群与大堡礁内其他区域的礁区群落的对比情况；
b) 诺福克群岛礁区的相对生物/生态价值；
c) 结合已有历史数据开展礁区现状的历史对比，以揭示当前礁区的变化趋势；
d) 为这些礁区的长期监测提供可选方案。