National Coral Reef Monitoring Program: Towed-diver Surveys of Benthic Habitats, Key Benthic Species, and Marine Debris Sightings of the Pacific Remote Island Areas from 2017-04-02 to 2017-04-20 (NCEI Accession 0164023)

The towed-diver method is used to conduct benthic surveys, assessing large-scale disturbances (e.g., bleaching) and quantifying benthic components such as habitat complexity/type and the general distribution and abundance patterns of live coral, Crustose Coralline Algae (CCA), macroalgae, and macroinvertebrates. Surveys are conducted in the Hawaiian and Mariana Archipelagos, American Samoa, and the Pacific Remote Island Areas as part of the NOAA National Coral Reef Monitoring Program (NCRMP). A suitable method for assessing relatively large areas of reef habitat, the method involves towing a pair of SCUBA divers—one benthic and one fish—behind a small boat for approximately 50 minutes following the ~15-m depth contour and covering about 2–3 km of habitat. Each diver is equipped with a towboard and attempts to maintain a constant elevation above the surface of the reef (~1 m) for the duration of the survey. A complete towed-diver survey is divided into 10, 5-minute segments, with visual observations recorded by 5-minute segment.

The visual estimate data provided in this dataset were collected during towed-diver surveys which includes percentage cover of total live hard corals, stressed hard corals, soft corals, sand, coralline algae, and macroalgae, and the number of individual macroinvertebrates (crown of thorns starfish (COTS), sea urchins, and giant clams). Benthic habitat complexity and type data are also collected as part of the survey with the following habitat type categories: continuous reef, spur and groove, patch reefs, rock boulders, pavement, rubble flat, sand flats, pinnacle, and wall.

The data were collected around the Pacific Remote Island Areas as part of the NOAA Pacific Islands Fisheries Science Center (PIFSC), Coral Reef Ecosystem Program (CREP) led mission in 2017.

本数据集采用拖曳潜水员法（towed-diver method）开展底栖生物调查，用于评估珊瑚礁的大规模扰动（如珊瑚白化），并量化底栖组成要素，包括生境复杂度/类型、活珊瑚、结壳珊瑚藻（Crustose Coralline Algae, CCA）、大型藻类及大型无脊椎动物的总体分布与丰度模式。
本调查作为美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）国家珊瑚礁监测计划（National Coral Reef Monitoring Program, NCRMP）的组成部分，在夏威夷群岛、马里亚纳群岛、美属萨摩亚及太平洋偏远岛礁区域开展。
作为适用于评估较大范围礁区生境的方法，拖曳潜水员法的操作流程为：将两名水肺潜水（SCUBA）潜水员——一名负责底栖生物观测、一名负责鱼类观测——拖曳于小艇后方，沿约15米等深线行进，单次调查时长约50分钟，覆盖约2至3公里的礁区生境。每名潜水员均配备拖曳板，需在整个调查周期内保持距礁体表面约1米的恒定高度。完整的拖曳潜水员调查被划分为10个5分钟的分段，所有目视观测记录均按5分钟分段进行归档。

本数据集包含的目视估算数据采集自上述拖曳潜水员调查，内容涵盖活硬珊瑚总盖度、受胁迫硬珊瑚盖度、软珊瑚盖度、沙质覆盖度、珊瑚藻盖度及大型藻类盖度，以及大型无脊椎动物（长棘海星（crown of thorns starfish, COTS）、海胆及砗磲）的个体数量。调查同时采集底栖生境复杂度与类型数据，生境类型分类包括：连续礁、脊沟系统、斑礁、岩礁、礁坪、碎石滩、沙质滩、海山及礁壁。

本数据于2017年由美国国家海洋和大气管理局太平洋岛屿渔业科学中心（Pacific Islands Fisheries Science Center, PIFSC）珊瑚礁生态系统计划（Coral Reef Ecosystem Program, CREP）主导的科考任务中，在太平洋偏远岛礁区域周边采集完成。