Environmental Management

, Volume 53, Issue 1, pp 147–162 | Cite as

Science and Management of the Introduced Seagrass Zostera japonica in North America

  • Deborah J. Shafer
  • James E. KaldyEmail author
  • Jeffrey L. Gaeckle


Healthy seagrass is considered a prime indicator of estuarine ecosystem function. On the Pacific coast of North America, at least two congeners of Zostera occur: native Zostera marina, and introduced, Zostera japonica. Z. japonica is considered “invasive” and therefore, ecologically and economically harmful by some, while others consider it benign or perhaps beneficial. Z. japonica does not appear on the Federal or the Oregon invasive species or noxious weed lists. However, the State of California lists it as both an invasive and noxious weed; Washington State recently listed it as a noxious weed. We describe the management dynamics in North America with respect to these congener species and highlight the science and policies behind these decisions. In recent years, management strategies at the state level have ranged from historical protection of Z. japonica as a priority habitat in Washington to eradication in California. Oregon and British Columbia, Canada appear to have no specific policies with regard to Z. japonica. This fractured management approach contradicts efforts to conserve and protect seagrass in other regions of the US and around the world. Science must play a critical role in the assessment of Z. japonica ecology and the immediate and long-term effects of management actions. The information and recommendations provided here can serve as a basis for providing scientific data in order to develop better informed management decisions and aid in defining a uniform management strategy for Z. japonica.


Seagrass Zostera japonica Zostera marina Invasive species management 



The authors thank the following individuals for valuable comments and discussion on draft versions of this manuscript, H. Berry, R. Carman P. Dowty, B. Dumbauld, M. Goehring, L. Nelson, W. Nelson, F. Short, B. Reeves, R. Virnstein, S. Yost, and four anonymous reviewers. Authors also thank J. Ruesink for access to Manila clam weight data. The information in this document has been funded in part by the U.S. Army Corps of Engineers and Environmental Protection Agency. It has been subjected to review by the National Health and Environmental Effects Research Laboratory’s Western Ecology Division and by the US Army Corps of Engineers, Environmental Research and Development Center and approved for publication. Approval does not signify that the contents reflect the views of the agencies, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.


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Copyright information

© Springer Science+Business Media New York (outside the USA) 2013

Authors and Affiliations

  • Deborah J. Shafer
    • 1
  • James E. Kaldy
    • 2
    Email author
  • Jeffrey L. Gaeckle
    • 3
  1. 1.Engineer Research and Development CenterUS Army Corps of EngineersVicksburgUSA
  2. 2.Western Ecology DivisionUS EPANewportUSA
  3. 3.Aquatics Division, Washington State Department of Natural ResourcesNearshore Habitat ProgramOlympiaUSA

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