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Hot weather causes explosion of duck weed on London’s canals

Pea soup, a garden lawn or the next super food craze? The high temperatures being enjoyed by the capital are having an interesting side effect, with London’s canals being invaded by a green carpet of weed.

Duck weed in Little Venice

The Trust has begun the painstaking task of removing millions of pieces of floating duck weed from the water, which multiplies rapidly in the heat.

While an individual piece of duck weed is no bigger than a ladybird, congregated together they can resemble a thick carpet across the canal. This accumulates litter, which can be problematic for the hundreds of boats and leisure craft on the water. The weed is not harmful to people, but dogs and other animals have been known to mistake it for grass, and ended up in the water. Significantly, if left to thrive, it can cause problems for other aquatic wildlife by starving it of oxygen and sunlight.

This week alone, over 70 tonnes of duck weed has been collected by the Trust's teams.

Tim Mulligan, Canal & River Trust waterway operative, says: "Duck weed is really noticeable on some sections of the canal at the moment. While I'm on our boat removing it I'm asked what it is all the time. Some people says it looks like a garden lawn, or pea soup, or green porridge. The food references are interesting though, as we found that people in South East Asia regularly eat duck weed because it's got loads of protein in it. I see plenty of ducks tucking into it, so I guess it could be the next super food craze. Although in all seriousness hopefully nobody would be foolish enough to eat it from the canals here in London."

The Trust is reminding people to take care when out walking with dogs and with their families, and asking people not to throw litter onto the weed.

Last Edited: 21 July 2016

photo of a location on the canals
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