New Brunswick

'Zombie plant' threatens to take over St. John River and other waters

Halloween might still be weeks away but a new invasive species known as "the zombie plant," has started lurking in the waters of the St. John River.

The Eurasian water milfoil shouldn't be cut because it can multiply quickly, says expert

The Eurasian water milfoil, an invasive aquatic plant, has been found along the St. John River. (CBC)

Halloween might still be weeks away but a new invasive species known as "the zombie plant," has started lurking in the  St. John River.

The Eurasian water milfoil, the plant that won't be killed, has been found in the river from Nackawic all the way down to Nerepis, more than 130 kilometres away.

The plant has also been reported in the Kennebecasis River.

"Unlike a zombie, it doesn't come back from the dead, but I presume it has earned that name because it is so resilient and so difficult to kill," said Meghann Bruce, a research scientist with the Canadian Rivers Institute in Fredericton.

Although the plant isn't toxic, it is "extremely invasive," beating out many native plants in the water, which can change habitats in the river.

Eurasian water milfoil, which has green branches and red tips that are visible above the surface, is native to Europe, Asia and northern Africa. The plants can grow in both deep and shallow water.

Where is it?

The Eurasian water milfoil is an aggressive competitor against native plants, contributing to less biodiversity in lakes and rivers. (Organisme des bassins versants de la Haute-Côte-Nord)

Bruce said the plant can survive a wide range of conditions and easily multiply. When cut from something such as a boat propeller, for instance, each fragment can go on to form a new plant.

"Pieces of the plant break off, float around in the river, and each of those pieces of branches can form roots and make an entire, different plant when they settle," she said.

The plant has already been found in Maine, British Columbia, Ontario and Quebec waters.

Bruce said the plant could've come through any of those states or provinces, but experts don't know for sure.

According to Ontario's invading species awareness program, the plant might've been introduced to the country through the aquarium trade or in ship ballast.

Prevention is key

The Eurasian water milfoil isn't dangerous to humans, but it can hinder boats and compromise fishing grounds. It can also decrease property values on waterfronts where it grows.

Bruce said it's next to impossible to eradicate the plant in the St. John River, but it's important to prevent it from spreading to other bodies of water.  

To do that, Bruce said it's important to clean, drain and dry any watercraft after it's taken out of the water.

"If you think of a boat prop going through a bed of this plant that is very dense, it creates thousands of fragments," she said.

"It only takes one of those fragments to introduce to a new water body, and the plant there can establish."

With files from Information Morning Fredericton

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