Marine Benthic Habitat Mapping in the Golden Gate National Recreational Area

Greene, H.; Williams, T.; Edwards, B.; Dieter, B.; Endris, C.; Ryan, H.; Niven, E.; Phillips, E.; Barnard, P.; Harmsen, F.

Final report for the pilot benthic habitat mapping efforts at Golden Gate National Recreation Area. The objective of this project was to compile available regional seafloor mapping data for San Francisco Bay and to interpret newly collected data provided through the California State Mapping Program (CSMP) and the United States Geological Survey (USGS) to construct benthic habitat and geologic maps of the submerged lands of the GGNRA. The habitat maps were constructed using the same habitat classification scheme and mapping code presently being used for the development of the CSMP habitat maps (Greene et al., 1999, 2005, 2007a). The maps comprise an integration of previous seafloor maps such as the San Francisco Bay anthropogenic habitat disturbance maps (Greene et al., 2007b). This is a pilot project that will guide future habitat characterization projects at other NPS ocean and coastal parks and serves as a working template for further mapping efforts in the GGNRA and the development of other derivative or thematic maps that may evolve from this project. The result of work by the Moss Landing Marine Laboratories (MLML)/Center for Habitat Studies/NPS/USGS is independently useful. The data obtained from this phase, however, may be used for future phases, subject to satisfaction of the data, desirability for additional data, and available funding. Five 1:24,000 scale map sheets and one high resolution 1:7,500 scale selected inset maps sheet have been constructed for this project. These sheets represent the MBES bathymetric images and backscatter or acoustic intensity data sets used to construct the geologic and habitat maps sheets. Habitat types are characterized as potential habitats that may represent true habitats for a particular species or assemblage of organisms but biological information is needed to confirm the true habitat types. Fifty-two distinct habitat types and 15 geologic units have been mapped. San Francisco Bay, a major seaport fringed with high-density urban development, is a highly disturbed environment. Unnatural disturbances to bay and estuary floors impact the ecology significantly in the form of altering benthic habitats that reduce the propagation and sustainability of demersal organisms and associated fisheries. The shallow bay or estuary margins, such as wetlands or tidelands, and associated flora, provide critical habitat for a multitude of fauna including birds, fishes, mammals and amphibians (Nichols et al., 1986). However, few investigations of the deeper parts of these inlets have been undertaken even though human disturbances of biotic and abiotic resources are increasing and altering natural processes (Greene et al., 2007b). One of the goals, therefore, of the maps constructed for this project is an attempt to identify potentially important benthic habitat types (especially for rockfish, lingcod, and other recreationally important fisheries habitats) that could merit protection to sustain the local natural ecology and economically important fisheries.

Marine Benthic Habitat Mapping in the Golden Gate National Recreational Area

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