Projects in Progress:

Introduction to Eelgrass Meadows

Eelgrass Mapping Project

2004 to June 2005

Eelgrass Mapping Project

June 2005

Eelgrass Restoration Project

2005-2007

Eelgrass Restoration Project

August 2005

Eelgrass Restoration Project

April 2006

Eelgrass Restoration Project

May 2006

Introduction to Eelgrass Meadows

Eelgrass meadows represent one of the habitat types that are threatened by estuarine development.  Various types of disturbance in coastal and estuarine environments have led to a decline in seagrass abundance around the world.  

Seagrasses, including eelgrass have been used as indicators or nearshore ecosystem health in many areas of the world.  The complex and intricate food webs of an eelgrass meadow rival the world’s richest farmlands and tropical rainforests. From an unstructured muddy/sandy bottom grows a myriad pattern of leaves that supply nutrients to fish, shellfish, waterfowl and about 124 species of faunal invertebrates. The plants offer surface area for hundreds of species.

The high biological diversity available in eelgrass systems provides food in several ways. In the Trent River delta on Vancouver Island, for example, 124 species of birds have been identified, over 38,000 individuals. Forty eight per cent were observed using the intertidal eelgrass (Z. japonica) of the delta for feeding, foraging or preening at some time during the year.    

Native eelgrass (Z. marina) plants retain their leaves year-round. Because the plants are rarely exposed to air, the leafy habitat is available to marine animals almost continuously. Living in the web of blades, animals, including juvenile salmon, young herring, plume hydroids, nudibranchs, anemones, jellyfish, clams, scallops, cockles, shrimp, spider, red rock and dungeness crabs, sea stars, moon snails and sand dollars find protection and food. The mat of underground rhizomes prevents the easy movement of predators into and through the sediment, and the thick canopy of blades makes quick movements by larger predators (fish and birds) more difficult.

Only about 5% of eelgrass is consumed by direct grazing. Only a few species eat the leaves. Among the consumers are snails and amphipods, important prey for fish and birds. Great Blue herons, dabbling ducks, widgeon, pintail and mallard ducks and Black Brant geese are among the millions of shorebirds that use eelgrass beds for foraging. Over 2.3 million birds, representing 150 species, use the intertidal flats of the Fraser River annually.  Recently, in the Strait of Georgia, green urchins and Canada Geese have been observed consuming significant amounts of eelgrass and seriously impacting the local eelgrass populations. (C. Durance, pers. com.)

Central to the marine food web is the Pacific herring, contributing 30% to 70% to the summer diets of Chinook salmon, Pacific cod, lingcod, and harbour seals in southern B.C. marine waters. Herring roe constitutes an important component of the diets of migrating seabirds, grey whales, and invertebrates. About 500 linear km of B. C. coastline turn milky-white every March and April as a result of the herring’s release of sperm around the eggs (roe) spawned directly on eelgrass and also on algae which is often epiphytic on eelgrass.

Eelgrass detritus provides the basis for a chain of consumers in the open ocean living as far as 10,000 meters in depth.  The extensive root system of the plants helps stabilize sediments and prevent erosion along the BC coastline. Damage to eelgrass can affect an entire ecosystem as well as the stability of our shorelines.

Eelgrass Mapping Project - 2004 to June 2005

The Eelgrass Mapping Project 2004 was funded by Eco-Action and was a partnership with SeaChange Marine Conservation Society and the Seagrass Conservation Working Group. The objective was to gather information on the current extent of eelgrass beds in the Cowichan estuary and to train community members in eelgrass mapping protocol.

Eelgrass Mapping Project - June 2005

The Cowichan Community Land Trust completed mapping the eelgrass meadows in the Cowichan Estuary. They had lots of help from great volunteers, and are always looking to meet new faces.

Eelgrass Restoration Project - 2005-2007

Now that we are familiar with where the eelgrass beds are in the area, we will be working on some site assessments. We will be looking at potential sites for transplanting as well as existing beds where we can gather transplants.

The site assessment research has two dimensions. We will be out in the field, sampling and measuring, and we are also working on gathering information to paint a historical picture of eelgrass in the Cowichan Bay. To do this we are seeking information or knowledge of eelgrass from the community. This may be a memory of where the eelgrass grew in the past, your grandma’s favourite recipe for eelgrass root shoot stew, or a theory on what might have caused its decline. Any anecdote or tale involving eelgrass in the bay is what we are looking for. We’d love to hear from you.

An Eelgrass Restoration meeting was held on Wednesday, June 8^th. The meeting took place at the Mellowside Café in Cowichan Bay.

Interviewing long term residents, fisherman, and other community members that have spent quite a bit of time in the Cowichan Bay has allowed us to understand what the Bay looked like in the past. We heard many great stories about octopus wrestling and harvesting crabs, flounder, skates and clams from the eelgrass beds. Thank you to everyone who helped put this record together.

Putting the general locations of where eelgrass grew in the past, beside the present locations of eelgrass beds gives us an idea of where we should be transplanting eelgrass. Any inconsistencies in present and past locations have become potential transplant sites. For example, it seems that the North side of the Cowichan Bay, off Khenipson Rd, did have eelgrass in the 70’s and 80’s. At the present time there is none, but knowing that this area did support eelgrass in the past suggests it might be worth trying again. We will be looking at sites more carefully through the summer, exploring limiting factors, and testing the areas ability to support new growth.  

On June 26 the CCLT hosted an eelgrass ecology workshop with Nikki Wright from SeaChange Marine Conservation Society. Thank you to Nikki, and all our volunteers for attending. We all learned a lot about what role eelgrass plays in the ocean, and the environmental conditions it prefers. Proceeding to the beach, we managed to get our hands and feet wet looking at different types of eelgrass, and seeing some of the creatures that exist in the food web created by the eelgrass bed. 

Next on the agenda is a site assessment training workshop. Cynthia Durance from Precision Identification will be joining the Land Trust on July 23, in Cowichan Bay. Individual sites will be assessed with a series of criteria to determine whether the area will support eelgrass growth again. The day should take us out on a boat looking at the substrate, elevation, salinity, current velocity, available light, and pH of potential transplant sites.  After this analysis we should have a firm idea of where to plant.

The following week, July 31, a test plot of about 100 eelgrass transplants will be rooted in a selected site. In the spring of next year there will be a larger transplant done, putting the transplants in a new location right before the most productive time of year.

Eelgrass Restoration Project - August 2005

Restoring eelgrass is not quite as simple as one may think. The CCLT had to call in a team of eelgrass experts, Cynthia Durance from Precision Identification, and Nikki Wright from SeaChange.

With their help, the CCLT, and many great volunteers attended two workshops on July 23 and July 31, receiving training in eelgrass site assessment and transplant methodology. The days were hands-on as volunteers harvested, prepared, and transplanted 400 eelgrass shoots. SCUBA divers gently pulled shoots from the donor bed, located around the boat launch ramp in Cowichan Bay. The shoots were then individually anchored and transported across the bay, to two different barren sites. These transplant sites are located between the terminal and the closest log boom, and the second one between the last log boom and the shore off Kneipson Rd. Two groups of 100 plants were transplanted at each of these two sites, testing the ability to support eelgrass growth again. If all goes well a large transplant will take place in the spring.

The CCLT could not have done this without the help and dedication of our volunteers. Thank you all for giving us part of your weekends to help preserve and enhance eelgrass beds in the Cowichan Bay. Stay tuned for a date to revisit the transplants, and a link to the Community Mapping Network illustrating eelgrass in the Cowichan Bay.

Phone 746-0227 or email CCLT  

Good news! Our Eelgrass transplants from last year are surviving and multiplying! We were out in March checking on their progress and have found that 2 sites have increased by 70-80% which is a great success. The other 2 sites weren't found but in September they were being used as forage by the swans. I think we planted a buffet for them in that area!

Now we have confirmed that eelgrass will thrive in the selected sites we are starting up another round of eelgrass restoration.

We are looking at the last weekend in April - the 29th and 30th for the transplant dates - divers will be harvesting shoots on Friday in preparation for the Saturday land volunteers. We will need many hands on land to tie the shoots with their weights and 2-3 buddy pairs of divers for harvesting and planting on both days.

To help us organize this larger transplant I hope to meet with our volunteers from last year to get some suggestions as to how to make this transplant more efficient. As well, I would like to invite anyone who wasn't available last year but is interested in helping out with this transplant to join us in the planning stage.

The planning meeting is set for Wednesday, April 19th at 7pm. Please RSVP so I know whether we can meet at the CCLT office or if a larger space is needed.

Thanks to all for your continued support - we couldn't do it without you.