NCCOS Mapping: Characterizing Benthic Habitats West of Saipan, Commonwealth of the Northern Mariana Islands (CNMI), 2018-11-05 to 2022-04-29 (NCEI Accession 0291792)

This data package contains information and maps showing the geology and biology of select submerged lands (0 to 40 meters deep) offshore of western Saipan, Commonwealth of the Northern Mariana Islands (CNMI). This information and maps were developed using benthic information from underwater photographs, environmental predictor variables derived from satellite imagery and bathymetry, and machine learning modeling approaches. From this process, two types of map products were created. The first type describes the spatial distribution of 5 substrate and 14 biological cover types, where each grid cell denotes the probability (0 to 100%) that a given habitat is present. The second product was a classified map depicting the 7 most common combinations of substrate and cover types (plus artificial structures). The performance and accuracy of these products were evaluated using an independent of underwater photographs. The overall accuracy of the classified map was 91.5% with user’s accuracy of individual habitat classes between 84% and 100% correct. The substrate and cover predictions had little bias (𝑥̅ error = 0.01 ±0.01 SE), good to excellent ability to discriminate between presences and absences (𝑥̅ area under the curve = 0.82 ±0.02 SE) and they explained almost a quarter of the variation in the data (𝑥̅ percent deviance explained = 23.8% ±2.9 SE).
Over 95 square kilometers (km2) of seafloor was characterized west of Saipan, CNMI. Overall, ‘Live and Upright Dead Coral Reef, Mixed Algae’ was the most abundant habitat type mapped inside and outside the Lagoon, comprising 32% (31 km2) of the area. The largest, continuous patches were located outside the Lagoon north Susupe Point, as well as inside the lagoon on the reef crest and back reef north of the harbor channel. Most live coral (all species) observations were documented outside the Lagoon from the harbor channel to Agingan Point, as well as inside the Lagoon north of Garapan. Enhalus acoroides and Halodule uninervis seagrass were both located exclusively inside the Lagoon, from Tanapag Beach south to Oleai as well as north of Tanapag to Pau Beach and south of Garapan to Agingan Point, respectively. Endangered Species Act (ESA) protected corals (i.e., Acropora globiceps) were documented at 4 sites outside the Lagoon, located seaward of the reef crest between Susupe and Agingan Points. No nuisance species (i.e., C. vieillardi) or crown of thorns sea star (COTS) were photographed outside the Lagoon. The prevalence of coral bleaching and marine debris were also very low outside the Lagoon (<0.7% and <0.9%, respectively). Theses maps mark the first time that the seafloor area outside the Lagoon has been mapped since 2005, providing an updated inventory of marine resources and new baseline for future monitoring and management decisions in the region.

本数据包包含有关萨帕兰岛（北马里亚纳群岛联邦）西部海域（深度在0至40米之间）选定海底地质和生物学的信息和地图。该信息和地图是通过水下摄影所获取的底栖信息、由卫星图像和测深数据派生的环境预测变量，以及机器学习建模方法开发而成。经此过程，生成了两种类型的地图产品。第一种类型描述了5种底质和14种生物覆盖类型的空间分布，其中每个网格单元表示特定栖息地存在的概率（0至100%）。第二种产品为分类地图，展示了7种最常见的底质和覆盖类型组合（包括人工结构）。这些产品的性能和准确性通过独立的水下摄影进行了评估。分类地图的整体准确率为91.5%，单个栖息地类别的用户准确率在84%至100%之间。底质和覆盖预测的偏差极小（平均误差 = 0.01 ± 0.01 标准误差），具有良好的至卓越的区分存在与不存在的能力（平均曲线下面积 = 0.82 ± 0.02 标准误差），并解释了数据中近四分之一的变异性（平均变异解释百分比 = 23.8% ± 2.9 标准误差）。在萨帕兰岛（北马里亚纳群岛联邦）西部海域，对超过95平方公里的海底进行了特征描述。总体而言，‘活立珊瑚礁，混合藻类’是在潟湖内外最为丰富的栖息地类型，占区域面积的32%（31平方公里），最大的连续区域位于潟湖以北的Susupe点及其潟湖内的礁顶和港池北部的后礁。大部分活珊瑚（所有物种）的观测记录在潟湖外，从港池至Agingan点，以及潟湖内的Garapan北部。Endangered Species Act（ESA）受保护的珊瑚（例如，Acropora globiceps）在潟湖外4个地点进行了记录，位于Susupe和Agingan点之间的礁顶外侧。在潟湖外未拍摄到有害物种（例如，C. vieillardi）或 Crown of Thorns 海星（COTS）。珊瑚白化和海洋垃圾的普遍率也非常低（分别为<0.7%和<0.9%）。这些地图标志着自2005年以来首次对潟湖外海底区域进行测绘，为该区域的海洋资源更新清单和未来监测与管理决策提供了新的基线。