Waterways workers weed out invader

The green weed, which is notorious for clogging up boat propellers, choking off oxygen in the water for wildlife and spreading at a rate of knots, was hauled out of the canal yesterday.

British Waterways chiefs were quick to assure local residents that the weed was not blue-green algae, Cyanobacteria, which form toxic green scum when they die and have spread in many lakes and canals across Britain this summer.

The toxin causes sickness and muscle pain in humans and can prove fatal for animals. It has been blamed for the death of three dogs at Burton Riggs nature reserve at Seamer, near Scarborough, in June.

A British Waterways spokeswoman said: “Blanket weed is harmless to people and pets but it spreads very quickly and clogs up the waterways.

“It can be very bad for boats because it clogs up propellers but it can also be bad for local wildlife because it sucks the oxygen out of the water.

“We have seen a bit of blue green algae nationwide this year but we always use specialised staff to remove it.”

There have been 83 algal incidents so far this year – a month into the three-month algae season – a higher than usual amount, according to the Environment Agency.

In 2010, the number of incidents reached 225, while the peak year was 2005, when 226 were reported.