Invasive Species
Greater Farallones

Asian kelp, or "wakame" (Undaria pinnatifida) is one of the invasive species that is of the highest concern to the Greater Farallones National Marine Sanctuary. Credit: Chad King, MBNMS, NOAA

Why is it a concern?

Introduced species in the marine and estuarine environment can alter species composition, threaten the abundance and diversity of native marine species, interfere with the ecosystem's function, and disrupt commercial and recreational activities.  In addition to known vectors for species introduction (e.g., abandoned or moored vessels, ship wrecks and cargo containers, mobile equipment, drifting debris, and intentional release of non-native animals and plants), there is concern that climate change will promote the spread of introduced species into areas where they may have previously been restricted.  Although there are several agencies and organizations that document and eradicate introduced species in the area, a coordinated effort is need to compile existing information and data, identify data gaps, and update maps of abundance and distribution.  It is also necessary to identify the pathways by which new species are introduced into the sanctuary, prioritize which pathways pose the greatest threat to Sanctuary resources, and develop outreach tools to reduce the intentional and unintentional release of non-native plants and animals into the sanctuary.

San Francisco Bay, adjacent to the Greater Farallones sanctuary, is considered the most invaded aquatic ecosystem in the world, with more than 255 introduced species. The Bay's close proximity to the sanctuary elevates the risk of new introductions to Greater Farallones estuaries.  Of the highest concern to the sanctuary are: wakame (Undaria pinnatifida), green crab (Carcinus maenas), Japanese false cerith mudsnail (Batillaria attramentaria), and Atlantic smooth cordgrass (Spartina alterniflora) and its hybrids with the native cordgrass Spartina foliosa.  There is also concern about an invasive tunicate Didemnum sp. that has been observed in Drakes Estero, Tomales Bay and Bodega Harbor, CA, and has the potential to cause great ecological and economic damage.  This tunicate is known to spread rapidly, alter benthic habitats, and overgrow sessile organisms such as sponges, anemones, bryozoans, hydroids, macroalgae and native tunicates. 

An inventory of introduced species was completed in 2005, and it is estimated that about 143 species of invasive species are present in the sanctuary. Current levels, in terms of abundance, distribution, and diversity of introduced species are not fully documented in the sanctuary and the impacts, existing or potential, are not well understood.  A complete inventory and mapping of abundance and distribution of introduced species is needed to enable tracking, future detection, and to develop and prioritize plans for removal or control.  The inventory will also aid in the development of citizen science early detection and removal projects.

Overview of Research

The Greater Farallones National Marine Sanctuary is actively seeking research partners to conduct work connected to Invasive Species as a sentinel issue.

Project Name PI and contacts Links

Green Crab Removal, Seadrift Lagoon and Green crab control methods: Evaluating factors important for eradication of Carcinus maenas.

Ted Grosholz


Control of Spartina alterniflora

Mischon Martin, Marin County


Climate Change and Biological Invasions

Ted Grosholz

Bolinas Lagoon Restoration

Kate Bimrose


Science Needs and Questions

The best available science is used by Sanctuary scientists and managers working to address priority resource conservation and management issues. As priorities change and new issues emerge, each Sanctuary develops new science needs and questions and works with partners to address them.

  • What are the abundance, distribution and diversity of introduced species throughout the sanctuary habitats?
  • How may GFNMS integrate new or updated introduced species inventories with the existing monitoring programs?
  • What and where are the data gaps for detecting and documenting introduced species?
  • What introduced species are most likely to be invasive and cause impacts to sanctuary resources?
  • Where are the priority areas and species for early detection and eradication?
  • Where, how, and for how long should monitoring be conducted in the sanctuary to further our understanding of species already introduced to the sanctuary and to detect early invaders?
  • What are the most feasible and efficient methods of eradication, containment or management for existing and future introduced species in the sanctuary?  What are the permits required to develop a fast tracked removal of invasive species? Are there pre-planned removal protocols and permits?
  • What are the ecological and economic impacts of introduced species within the sanctuary?

Education and Outreach Material

Please refer to the Greater Farallones National Marine Sanctuary website to learn more
about education and outreach materials.


Bullard, S.G., G. Lambert, M.R. Carman, J. Byrnes, R.B. Whitlatch, G. Ruiz, R.J. Miller, L. Harris, P.C. Valentine, J.S. Collie, J. Pederson, D.C. McNaught, A.N. Cohen, R.G. Asch, J. Dijkstra and K. Heinonen. 2007. The colonial ascidian Didemnum sp. A: current distribution, basic biology and potential threat to marine communities of the Northeast and West coasts of North America. Journal of Experimental Biology and Ecology 342:99-108.

Byrnes, J. E., P.L. Reynolds and J.L. Stachowicz. 2007. Invasions and extinctions reshape coastal marine food webs. PLoS ONE 2(3): e295. doi:10.1371/journal.pone.0000295.

Byrnes, J.E. Unpublished data. List of nonindigenous species of Gulf of the Farallones and Cordell Bank national marine sanctuaries. University of California, Davis, CA.

Cohen A. and J. Carlton. 1998. Accelerating invasion rate in a highly invaded estuary. Science. 279:555-558.

deRivera, C.E., G.M. Ruiz, J. Crooks, K. Wasson, S. Lonhart, P. Fofonoff, B. Steves, S. Rumrill, M.S. Brancato, S. Pegau, D. Bulthuis, R.K. Preisler, C.G. Schoch, C.E. Bowlby, A. DeVogelaere, M. Crawford, S.R. Gittings, A.H. Hines, L. Takata, K. Larson, T. Huber, A.M. Leyman, E. Collinetti, T. Pascot, S. Shull, M. Anderson and S. Powell. 2005. Broad-scale non-indigenous species monitoring along the west coast in national marine sanctuaries and national estuarine research reserves. Report to National Fish & Wildlife Foundation. Smithsonian Institute, National Estuarine Research Reserve System, National Marine Sanctuary Program, Washington, D.C. 125 pp.