Habitat--Offshore of Tomales Point, California

This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of Tomales Point map area, California. The polygon shapefile is included in "Habitat_OffshoreTomalesPoint.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreTomalesPoint/data_catalog_OffshoreTomalesPoint.html. Using multibeam echosounder (MBES) bathymetry and backscatter data, potential marine benthic habitat maps were constructed. The habitats were based on substrate types and documented or "ground truthed" using underwater video images and seafloor samples obtained by the USGS. These maps display various habitat types that range from flat, soft, unconsolidated sediment-covered seafloor to hard, deformed (folded), or highly rugose and differentially eroded bedrock exposures. Rugged, high-relief, rocky outcrops that have been eroded to form ledges and small caves are ideal habitat for rockfish (Sebastes spp.) and other bottom fish such as lingcod (Ophiodon elongatus). Habitat map is presented in a map format generated in a GIS (ArcMap), and both digital and hard-copy versions will be produced.本DS 781数据集的此章节提供了加利福尼亚州托马莱斯角近海制图区域的海底生境地图相关数据。多边形形状文件打包于"Habitat_OffshoreTomalesPoint.zip"压缩包中，可通过http://pubs.usgs.gov/ds/781/OffshoreTomalesPoint/data_catalog_OffshoreTomalesPoint.html获取。 本研究借助多波束测深声呐（multibeam echosounder, MBES）获取的水深地形与反向散射数据，构建了潜在海洋底栖生境地图。该类生境以底质类型为分类基础，并通过美国地质调查局（United States Geological Survey, USGS）采集的水下视频影像与海底样品完成了地面实况验证。此类地图涵盖多种生境类型，覆盖范围从平坦松软的未固结沉积物覆盖型海底，到坚硬、变形（褶皱）或表面高度粗糙且受差异性侵蚀的基岩露头区域。经侵蚀形成岩架与小型洞穴的崎岖高地形起伏岩石露头，是石斑鱼（rockfish, Sebastes spp.）以及蛇齿单线鱼（Ophiodon elongatus, lingcod）等其他底栖鱼类的理想栖息生境。本次生境地图采用ArcMap地理信息系统（Geographic Information System, GIS）生成的制图格式呈现，将同时提供数字版与纸质版两种成果形式。