By Doug Leier
Following discovery of zebra mussels in North Dakota’s Lake Ashtabula in May, the good news is that over the course of the summer and early fall, the North Dakota Game and Fish Department’s searches for additional new zebra mussel infestations all came back negative.
On the other hand, recent assessments of these invasive aquatic nuisance species in North Dakota waters where they already exist provide a good example of how quickly zebra mussel populations can expand once they are established in a new environment.
Adult zebra mussels were first detected in the Red River, which flows between North Dakota and Minnesota, in fall of 2015. Since then, Game and Fish has received many reports of zebra mussel findings up and down the Red, including a presence on water intake filters at the Grand Forks city water treatment plant.
This fall, following the initial discovery of zebra mussels in Lake Ashtabula in Barnes County, some boat docks, fishing piers and boat lifts removed from the lake have been covered with zebra mussels of all sizes.
Game and Fish aquatic nuisance species coordinator Jessica Howell says on this week’s Outdoors Online webcast that zebra mussels were reported as far north as Karnack Landing, which is nearly 20 lake miles north of Baldhill Dam which forms Lake Ashtabula.
“They’re not very prevalent in the north end of the reservoir,” Howell said, “however, down by Bay Shore Marina and Sundstroms Landing (about 2 miles north of the dam), and then also down by the retainer gates at the face of the dam, they are very prevalent.”
Howell also says zebra mussels were confirmed in the Sheyenne River in Valley City, downstream from Lake Ashtabula.
Fortunately, that was the extent of new zebra mussel discoveries.
“This year we sampled over 100 waterbodies. Usually we sample about 30…,” Howell said. “We also added some adult (mussel) searching, particularly upstream of Lake Ashtabula, as well as a few other high-risk areas. So, we thankfully have not found any zebra mussels in any of those samples.
“We have gotten most of our results back already. But we wanted to make sure that any potential activities that we have done, have not spread any zebra mussels, and then, that recreational boating and angling have not caused any spread as well.”
Just because a major fishing and boating lake in North Dakota now has zebra mussels, doesn’t mean these prolific invasive species are destined to wind up in other waters as well.
“We have good regulations in place,” Howell said. “If all people follow our laws, it should really minimize the risk of spreading aquatic nuisance species. Those laws include removing vegetation, draining all water and removing drain plugs and leaving them open during transport … however, we do ask that people be more vigilant, knowing that there is potential to spread zebra mussels not only from Ashtabula, but from the Red River and the Sheyenne River as well.”
Featured Photo: Zebra Mussels attach themselves to a tire on a fishing pier on Lake Ashtabula. NDG&F Dept. Photo.
Leier is an outreach biologist with the North Dakota Game & Fish Dept.