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.本数据集（DS 781）的此部分提供了加利福尼亚州托马勒斯角近海海域海底生境地图相关数据。多边形形状文件包含于"Habitat_OffshoreTomalesPoint.zip"压缩包中，可通过http://pubs.usgs.gov/ds/781/OffshoreTomalesPoint/data_catalog_OffshoreTomalesPoint.html获取。 研究团队利用多波束测深声呐（multibeam echosounder, MBES）测深数据与背散射数据，构建了潜在海洋底栖生境地图。该生境分类以底质类型为依据，并通过美国地质调查局（United States Geological Survey, USGS）获取的水下视频影像与海底采样数据完成实地验证（ground truthed）。本地图涵盖多种生境类型，覆盖范围从平坦松软的非固结沉积物覆盖型海底，延伸至坚硬、褶皱变形或崎岖不平、经差异侵蚀出露的基岩露头。其中，经侵蚀形成岩架与小型洞穴的崎岖高起伏岩石露头，是岩鱼属（Sebastes spp.）以及长蛇齿单线鱼（Ophiodon elongatus，lingcod）等底层鱼类的理想栖息生境。本生境地图采用地理信息系统（GIS，ArcMap）制作，将同时提供数字版本与纸质版本。