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 displayed in EcoAtlas, including maps of mitigation projects and associated monitoring reports, were provided by third party consultants and compiled by the Long Beach Office of the Protected Resources Division, 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. This information is intended only for regional planning purposes and not for site-specific impact assessment purposes.

EcoAtlas displays eelgrass survey data along the coast from Humboldt Bay to San Diego Bay and information on over 60 eelgrass mitigation projects. Eelgrass surveys are available in the following systems:

  • Humboldt Bay and Eel River (2009)
  • Mendocino Coast (2014-2015)
  • Tomales Bay (2015, 2017)
  • Drakes Estero (2005)
  • San Francisco Bay (2004, 2009, 2014)
  • Elkhorn Slough (2014, 2016, 2018)
  • Morro Bay (2007, 2009, 2013)
  • Southern California
    • Agua Hedionda Lagoon (2013)
    • Alamitos Bay (2013)
    • Anaheim Bay (2013)
    • Batiquitos Lagoon (2013)
    • Lower Newport Bay (2004, 2007, 2010, 2014)
    • Mission Bay (2007, 2013)
    • Port of Los Angeles/Port of Long Beach (2013, 2014, 2018)
    • San Clemente Island (2014)
    • San Diego Bay (1993, 1994, 1999, 2000, 2004, 2008, 2011)
    • San Dieguito Lagoon (2013)
    • San Gabriel River (2013)
    • Santa Cruz Island (2015)
    • Santa Monica Bay (2015)
    • Seal Beach National Wildlife Refuge and Huntington Harbor (2013)

Project Timeline

  • Phase 1 (2011-2014)
  • Phase 2 (2015-2017)
  • Phase 3 (2018-2019)


2011 to 2019
Adam Obaza, NOAA/NMFS
Bryant Chesney, NOAA/NMFS
Programs and Focus Areas: 
Environmental Informatics Program
Wetland Monitoring & Assessment
Location Information
General Project Location(s):