After zebra mussels were detected on decorative aquarium moss balls sold in Wyoming pet stores, more than four months of tests have all come back negative for the harmful and invasive mussel.
At a Joint Travel, Recreation, Wildlife and Cultural Resources Committee meeting in May, state officials told lawmakers that the state was negative for zebra mussels, but testing of waste water was still ongoing at the time.
When the moss balls were found to have zebra mussels on them earlier this year, the worry was that Wyoming residents would flush fish tank water down toilets and drains, allowing the invasive mussel to infiltrate the waste water system.
After testing the waste water from the first week in March to now in Laramie, Cheyenne, Casper, Gillette, Rock Springs and Sheridan, all tests have come back negative for zebra mussel DNA.
“It’s really promising to get those results this early,” said Sara DiRienzo, the public information officer for the Wyoming Game & Fish Department.
But the department is still proceeding with care.
“We’re cautiously optimistic because zebra mussels have such a long life span,” DiRienzo said.
It remains unclear whether zebra mussels have the ability to survive in waste water systems.
If zebra mussels were to proliferate, they would be harmful to Wyoming’s infrastructure, in large part by clogging up water delivery systems. And because the animals are filter feeders, they have the ability to eat up planktons other species need to survive. Attempting to control them would cost tens of millions of dollars.
From March 3 until April 30, Wyoming Game & Fish spent roughly $51,000 on communications, testing, administration and greater scientific infrastructure to address the threat of zebra mussels. That number will undoubtedly increase as these prevention efforts continue. The entire aquatic invasive species state budget was $1.29 million in 2020.
Last year also brought significantly more boats into the state than 2019. In 2019, Wyoming Game & Fish sold 48,501 aquatic invasive species decals, and in 2020 the department sold 58,559. 2021 is already on track to see similar numbers to 2020.
“That’s a lot more risk coming into the state,” DiRienzo said.
Since the monitoring system launched in 2010, there have only been two instances of detecting live zebra mussels on watercrafts. Both times happened this year and both of the boats were coming from known zebra mussel hot spots, Lake Erie and Lake Powell.