Eelgrass (Zostera marina and Z. pacifica) is recognized as an important ecological resource in nearshore open coast areas, shallow bays, and estuaries throughout coastal California. Access to regional maps and related monitoring reports for eelgrass is crucial to monitor the extent of eelgrass habitat and how it is changing over time, evaluate the effects of coastal development projects on eelgrass habitat, and inform interested stakeholders and the public about eelgrass distribution. A system for tracking changes in the distribution and abundance of eelgrass may inform the effectiveness of ongoing conservation and restoration efforts.
All eelgrass data provided by EcoAtlas, including maps of mitigation projects and associated monitoring reports, were compiled from a variety of sources by the National Marine Fisheries Service West Coast Region. The regional survey maps for eelgrass represent the best available data about eelgrass distribution in coastal embayments and estuaries in California for the period 1994-2015. These data have been collected using a variety of methods and the survey results are not comprehensive. The data incorporated into these maps were derived from a restricted subset of surveys that have been conducted in different regions. Errors in the processing of GIS data can sometimes create inaccuracies in the spatial representations of geographic features. While these types of errors can be insignificant when creating large-scale maps, they become more problematic when relying on data to provide accurate information at very specific locations. Eelgrass distribution can change significantly over time. As ground conditions change, GIS data representing conditions at a specific point in time will becomes increasingly unreliable. Therefore, this information is intended only for regional planning purposes and not for site-specific impact assessment purposes.