"The complex and intricate food webs of an eelgrass meadow rival the world's richest farmlands and tropical forests." (Dr. Sandy Wyllie-Echeverria) Eelgrass monitoring

Eelgrass is a flowering marine plant found intertidally to about 50 feet deep. Two species of eelgrass are found in Boundary Bay – the native Zostera marina and the introduced Zostera japonica.
Eelgrass is vitally important for many reasons. The extensive root system helps to stabilize mudflat beaches and prevent erosion of shorelines. Over 80% of all commercial fish (including Pacific herring, salmon, Pacific cod and Lingcod), crab and shellfish depend on eelgrass habitat for at least part of their lifecycle and for 30 – 70% of their diet. Fish spawn, attached to the leaves, is an important food for migrating seabirds, grey whales, seals and other marine mammals. After they die, the decomposing blades of eelgrass turn into detritus which provides food for over 120 species of invertebrates. The invertebrates in turn provide food for fish, shorebirds, ducks and Brant geese. As well, eelgrass meadows provide shelter and nurseries for many invertebrate and fish species.

Eelgrass plays a critical role in moderating the effects of climate change. Recent reports by the United Nations Environmental Protection Department have noted that eelgrass and seagrass can store carbon with an efficiency of up to 90 times that of forests.

It is estimated that 15% of the world’s total seagrass areas have been lost. The trend towards habitat degradation continues as population increases in coastal regions. Eelgrass habitat is threatened by dredging and filing, structures such as docks and marinas and pollution.

Eelgrass monitoring at White RockSeagrasses cover 6,000,000 sq km worldwide but only 150,000 have been mapped. The B.C. Coastal Eelgrass Stewardship Project was implemented in 2002 to conserve and protect eelgrass habitat along the B.C. coast. Since then, over 1000 volunteers have mapped about 12,000 ha. along the B.C. coast. The B.C. Conservation Initiative is involved with mapping and monitoring eelgrass and entering the data into the Community Mapping Network.

The Friends of Semiahmoo Bay Society has been working with the Seagrass Conservation Working Group and B.C. Coastal Eelgrass Stewardship Project in Boundary Bay since 2002. Work this year will involve a continuation of the Mapping and Monitoring Program. An eelgrass transplant mitigation project was conducted at White Rock Pier after dredging by the City of White Rock in 2003. Another pilot project was conducted by Friends of Semiahmoo Bay Society at Blackie Spit in 2007 (See link to report at right).
Stay tuned for updates on how you can help protect this critical resource.

Methodology and Forms for Eelgrass Monitoring



Seagrasses are indicators of nearshore health and they are phenomenal carbon sinks, storing carbon for thousands of years, but seagrass is disappearing. As a member of the Seagrass Conservation Working Group (, Friends of Semiahmoo Bay Society contributes to the monitoring of eelgrass habitat and conservation initiatives of eelgrass in Boundary Bay. 

Come join us to learn about the importance of eelgrass, and get FREE training on how to map Eelgrass! Please visit the Birds on the Bay Calendar for workshop opportunities and events that might be of interest.

For further information, with questions or concerns, please contact Matt ( or

Learn More! Checkout this cool video about eelgrass and eelgrass mapping:

Photo: E. Kaarsemaker

Click Here for a copy of our informational eelgrass brochure.

Click here to download the Eelgrass Pocket Lami-guide

Read copies of our most recent Eelgrass Reports

Mapping Eelgrass using the Garmin 12XL GPS - A Manual for the West Coast of British Columbia

Click here to view