Province warns about aliens in moss balls

Alberta Environment wants people to destroy any moss balls they’ve bought this year to head off an invasion of alien mussels. 

The province put out a notice March 11 that invasive zebra mussels had been found in moss or marimo balls, and that Albertans should destroy any moss balls they bought this year as a result. 

A moss ball is a ball of moss commonly used by aquarium owners to absorb nutrients and maintain water quality, said Adrian Theroux-Nielsen, co-owner of St. Albert’s Oasis Fish and Reptile. Most pet and garden stores carry them. 

Zebra mussels are an invasive species notorious for their ability to clog water intake pipes, disrupt food chains and litter beaches with sharp shells. Native to Russia, they can be identified by their triangular striped shells that are less than three centimetres long. The mussels have no native predators in Alberta and can proliferate rapidly, with one female able to lay a million eggs a year.  

Theroux-Nielsen said zebra mussels won’t harm fish in an aquarium, but would devastate natural ecosystems if released as they reproduce like the Tribbles from Star Trek. 

“If you have one, by the end of the year you could potentially have up to 20,000.”

Mossy menace 

Alberta Environment first learned of the moss-ball menace on March 3 when officials in the state of Washington spotted zebra mussels in imported moss balls, said Nicole Kimmel, aquatic invasive species specialist with Alberta Environment. Several other states raised similar alerts later that week. Alberta Environment officials found live zebra mussels in shipment of 2,000 moss balls in Calgary on March 5, and issued an alert March 9.  

While the moss balls in question were from Ukraine, Kimmel said officials were concerned other moss balls could also contain these mussels.  

“We are considering all moss balls to be implicated,” she said. 

Zebra mussels have yet to establish themselves in Alberta, but could cost taxpayers millions of dollars a year if they did, Kimmel said. (Alberta Environment has pegged the cost of an invasive mussel infestation at $75 million per year.) 

Kimmel said crews are now calling Alberta pet and plant stores to have them take their moss balls off the shelves and submit them for testing.  

It is illegal to sell, own, release or transport zebra mussels in Alberta under the Fisheries Act, Kimmel said.  

Anyone who bought a moss ball in Alberta after Jan. 1, 2021 must destroy them immediately, Alberta Environment reports. The balls should either be frozen for 24 hours or boiled for a minute before being sealed in a plastic bag and tossed in the trash – not the drain, toilet or compost pile, as those methods could release mussels into the environment. Aquariums with moss balls should have their water sterilized with bleach prior to disposal and their surfaces and accessories treated with bleach or boiling water.  

Kimmel said these extraordinary measures are needed because zebra mussels release microscopic larvae in water and can survive for up to 30 days out of the water.  

Moss balls can hide zebra mussels because they are so dense, Theroux-Nielsen said. He advised fish owners to use less-dense plants such as Java or Flame moss instead, and to treat aquarium plants with plant dip (available in most pet stores) before use. 

Zebra mussels typically hitchhike into Alberta on boats, and the province has a team of mussel-sniffing dogs to try and detect them. The province has asked boaters to clean, drain and dry their boats and water equipment after use to prevent the spread of these mussels. 

Kimmel asked anyone who spots zebra mussels or moss balls in a store to call 1-855-336-BOAT (2628). 

Theroux-Nielsen said he plans to call his customers to advise them of the moss ball situation.  

Visit www.alberta.ca/aquatic-invasive-species-overview.aspx for more on zebra mussels.