GNWT urges moss balls be destroyed, warns of zebra mussels

Photo of moss balls shared on My Wild Alberta Facebook page.

Following reports of “invasive mussels” being found in moss balls sold in the NWT, the territorial government is urging residents to destroy any they may have purchased as soon as possible.

Marimo moss balls are a type of green algae commonly used to clean water in aquariums.

Since the beginning of the year, confirmed reports of moss balls infected with zebra mussels – a highly invasive species – have popped up in Alberta, Saskatchewan, and British Columbia. CBC Calgary reported on the concerns earlier this week.

In a news release on Friday, the NWT’s Department of Environment and Natural Resources (ENR) said it was “alerted to the presence of invasive mussels found in moss balls sold” in the territory.



The GNWT is worried about both zebra and quagga mussels.

The two are native to southwestern Europe and were introduced to freshwater lakes in Ontario in the 1980s. They breed quickly and spread by attaching to the bottoms of boats, docks, rocks, and plants. They often alter food chains in water bodies, posing a threat to local fish and wildlife.

They can also cause problems for hydro plants by clogging infrastructure.

According to a news release from Fisheries and Oceans Canada, the federal government has over the past four decades spent an estimated $7 billion to prevent, monitor, and manage the impacts caused by the mussels.



An image of zebra mussels found in moss balls from Fisheries and Oceans Canada.

Get rid of those balls

To prevent zebra or quagga mussels from being introduced to the territory’s environment, the GNWT is asking anyone who has purchased moss balls in the past year to destroy them and decontaminate the aquariums they were used in.

Moss balls should either be placed in a plastic bag and put in a freezer for at least 24 hours or put in boiling water for at least a minute and thrown in the trash afterward, according to the GNWT.

The territory warned residents not to flush moss balls down the toilet, dispose of them in compost, or dump aquarium tank pets, plants or untreated water down the drain or into any residential water system or waterway, as this could spread the mussels.

The GNWT said water from tanks should be treated before disposal, and both the aquariums and all paraphernalia should be washed out with chlorine bleach and water.  

A complete guide to the disposal of moss balls can be found of the BC government’s website.