Aquarium moss balls infested with zebra mussels found in Washington; Oregon consumers urged to check aquarium products

PORTLAND, Ore. (KTVZ) -- The Oregon Department of Fish and Wildlife reminded consumers Friday to "Destroy, Don't Dump" aquarium moss balls after invasive zebra mussels were detected in Washington state earlier this week.

Zebra mussels (Dreissena polymorpha) were found on the product Marimo moss balls (Aegagropila linnaei) which was shipped to a wholesale aquarium company in Renton, Wash. The state's Aquatic Invasive Species response team quickly disposed of the mussels and notified Oregon and other states of the detection.

Thanks to new regulations in Oregon since 2021, no infested products have entered the state through legitimate sales. However, at least seven states received moss ball products this year, including Washington, Colorado, Idaho, Montana, Alaska, Illinois, and Wisconsin. 

Fish and wildlife agencies are encouraging anyone who has purchased Marimo moss balls within the last year from any retailer to inspect the moss balls and take steps to decontaminate their aquarium or water garden for invasive zebra mussels.

The public is also encouraged to report zebra mussels by calling the Invasive Species Hotline at 1-866-INVADER or submit information online.

"Thanks to reporting by the aquarium and aquatic nursery industry and our partnership with Washington Department of Fish and Wildlife, we are less concerned that someone will purchase moss balls infested with zebra mussels in Oregon," said Keith DeHart, ODFW Invasive Species Coordinator.

"But, given the detection's proximity to Oregon, concern of illegal purchase and transportation into Oregon of these moss balls exists. We ask for the public's help with identifying and reporting this threat to Oregon's waterways," added DeHart.

A similar shipment was discovered in 2021 in Oregon and was quickly destroyed and removed from the supply chain. As a result, the Oregon Department of Agriculture now prohibits the import of moss balls infested with invasive zebra mussels to the state. According to the rule, moss balls may only be imported to Oregon if accompanied by a quarantine compliance certificate stating the commodity was inspected and found free of zebra mussels issued within seven days of shipment. Moss balls without proof of inspection within the seven days will be destroyed.

To date, the Columbia River basin is the only region left in the U.S. that is not infested with zebra mussels or the closely related quagga mussels, according to Oregon State University. However, with the detection of quagga mussels near Twin Falls last year, the threat is closer than it was in 2021.

Aquatic invasive species can quickly take over a waterbody, costing states more than $100 million per year to remove and destroy. Invasive mussels disrupt ecosystems, change the chemistry of water, and clog intake and delivery systems for drinking water, irrigation and hydro power.

People can safely dispose of infested moss balls by freezing them for 24 hours or boiling for a full minute before putting them in the garbage. Do not flush moss balls down the toilet, as zebra mussels could get into the water system.