Habitat--Offshore of San Francisco, California

This part of DS 781 presents data for the habitat map of the seafloor of the Offshore of San Francisco map area, California. The vector data file is included in "Habitat_SanFrancisco.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreSanFrancisco/data_catalog_OffshoreSanFrancisco.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.DS 781数据集的此部分提供了加利福尼亚州旧金山外海域制图区的海底生境地图相关数据。矢量数据文件存储于"Habitat_SanFrancisco.zip"压缩包中，可通过链接http://pubs.usgs.gov/ds/781/OffshoreSanFrancisco/data_catalog_OffshoreSanFrancisco.html获取。 研究团队利用多波束测深声呐（multibeam echosounder, MBES）获取的水深数据与背散射数据，构建了潜在海洋底栖生境地图。这些生境以底质类型为划分依据，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实地验证。该地图涵盖了多种生境类型，覆盖范围从平坦松软的未固结沉积物覆盖的海底，至坚硬、褶皱变形或起伏强烈、经差异侵蚀出露的基岩区域。那些经侵蚀形成岩架与小型洞穴的崎岖高起伏岩层出露区，是岩平鲉属（Sebastes spp.）及长蛇齿单线鱼（Ophiodon elongatus）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）生成的地图格式制作，将同时提供数字版与纸质版两种载体。