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Event aims to uproot invasive seaweed sweeping through Vancouver Island bay

Japanese Sargasso now taking over from Campbell River to Baja, California
The invasive seaweed Japanese sargassum is rapidly spreading in Maple Bay. (Sue Fryer photo)

Maple Bay is under assault from an invasive seaweed, and a group of local citizens is doing its best to keep it under control.

Jennifer Lawson, an internationally recognized artist who lives in the area, said the invasive weed called Japanese sargassum has been spreading through Maple Bay for the past several years and has now arrived at the far end of Sansum Narrows.

She said sargassum is very tall and aggressive and, at low tide, it lays across the top of the water looking “brown and ugly”.

Lawson said there are millions of seeds on every plant, and they are released and being spread through the bay with every wave, tide and paddle stroke, covering more of the bay every year.


“We have a very unique bay with a lot of biodiversity, but the sargassum sinks when it dies, covering all the many varieties of native seaweeds, starfish and other species on the seabed in a murky brown coating,” she said.

“We fear that the bay may be headed to being mono-culture, in which the sargassum will wipe out all the beautiful diversity of species we have here. The heat this summer has helped the sargassum spread in the bay more rapidly than before.”

Originally from Japan, it is thought the sargassum gained worldwide distribution on ships and other means.

On North America’s west coast, sargassum currently has a range stretching from Campbell River to Baja, California.


Lawson said she, Sue Fryer, who writes the Maple Bay newsletter, and other residents concerned about the proliferation of sargassum in the bay are hosting a Sargassum Removal Day on Maple Bay beach on July 25.

She said the community is invited to help pull sargassum from the water at low tide, which is between 11 a.m. and 2:30 p.m. on July 25.

Lawson said the person who collects the most sargassum will receive a print of a painting of Maple Bay from the north shore that she painted, and the next three runners up will receive slightly smaller prints.

“I expect that we’ll never get completely rid of it, but we think that holding this event on July 25 will make a big difference,” she said.

“The fact is that it’s under water so most people don’t even know about the threat that Maple Bay is under due to sargassum. There are so many fascinating things to see snorkeling in Maple Bay, including the varieties of fish, starfish, chitons and more that will all be affected if the habitat becomes a monoculture. So much stands to be lost. I really feel it’s our duty to act and try and save what is a beautiful bay.”

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Robert Barron

About the Author: Robert Barron

Since 2016, I've had had the pleasure of working with our dedicated staff and community in the Cowichan Valley.
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