Like a lot of states, North Dakota isn’t a stranger to aquatic nuisance species. Common carp, introduced to state waters more than a century ago, are the state’s biggest ANS culprit.
“Carp are pretty widespread and have been causing problems for years,” said Fred Ryckman North Dakota Game and Fish Department ANS specialist. “Most of the other aquatic nuisance species that we have a concern with were introduced into North Dakota much more recently.”
A decade after introducing North Dakota OUTDOORS readers to the threat of aquatic nuisance species to state fisheries and wetlands, the mission to educate and enforce laws to help reduce the spread of ANS in North Dakota continues.
In 2010, it became mandatory in North Dakota for anglers to drain water from livewells and baitwells prior to leaving a water body. Before that, anglers were encouraged, without the threat of a citation, to follow those practices.
“Aquatic nuisance species are especially problematic in terms of affecting fish populations or affecting the use of water bodies because they get to be so abundant,” Ryckman said.
In terms of the most recently introduced, curly leaf pondweed is found in fewer than a dozen North Dakota waters, while Eurasian water milfoil is found in just a couple. Silver carp were discovered in the James River in 2011, and the presence of this exotic fish is disquieting.
“Asian carp, bighead and silver carp, in particular, can be a big problem,” Ryckman said. “As of last summer, we documented that there are a few, literally a handful at most, silver carp still in North Dakota. It is a big concern that they are here.”
Not only are silver carp a biological threat, this exotic, which has a tendency to jump out of the water when spooked, can cause harm to boaters and others. “These fish are dangerous when they come out of the water like that,” Ryckman said. “You can imagine knee boarding, water skiing or just going around in an open boat and having these fish flying around …”
After day of walleye fishing on a popular North Dakota water, an angler inspects his boat motor for unwanted aquatic nuisance species hitching a ride.
An aquatic nuisance species that likely does more damage to lakes and waterways than any other has yet to be confirmed in North Dakota, but is creeping closer. “We are concerned about zebra mussels, which are in the Red River watershed in Minnesota, have moved down the Otter Tail River and are getting pretty close to the Wahpeton area,” Ryckman said. “As they continue to move downstream, with no barriers to prevent their movement, I see it as a matter of time before zebra mussels make it into the Red River.”
The damage is significant in waters elsewhere, Ryckman said, where zebra mussels are established in uncountable numbers. “The Great Lakes is probably the poster child for zebra mussels and these exotics have caused literally billions of dollars worth of economic losses with water supplies, water intakes and cleaning up some of the problems they have caused,” he said. “While it’s likely zebra mussels will become established, or become more abundant in the Red River, we’re not sure how they will fare ecologically. I just wish there was a barrier between Minnesota and the Red River so we wouldn’t end up with them.”
When zebra mussels are in the larval stage, the stage in which they will likely move from the Otter Tail into the Red, humans can’t make them out with the naked eye. “If you were fishing in contaminated waters like the Great Lakes, you wouldn’t even know if you had them in your livewell,” Ryckman said. “That’s why anglers must drain their livewells and baitwells.”
Adult zebra mussels, on the other hand, are about a half-inch and longer, much easier to spot, but difficult to remove from boats and other gear. “There are certainly some problems involved in moving adults, but probably the most likely way for zebra mussels to be moved is during the larval stage,” Ryckman said. “They’re invisible and people can move them without even knowing it. They could easily be moved in bait supplies, too.”
While Game and Fish Department officials are unsure of the fallout of zebra mussels in the Red River, they have witnessed the problems associated with curly leaf pondweed and Eurasian water milfoil.
“Typically, when an invasive first moves in it becomes very well established, develops a large population and sometimes dies back and becomes more a part of the environment, rather than a major problem,” Ryckman said.
Curly leaf pondweed, for instance, is in the Missouri River System, but hasn’t done much damage in lakes Sakakawea and Oahe, but has proliferated at times in bays and marinas in the Bismarck-Mandan area.
“We wish we didn’t have these aquatic nuisance species, they haven’t done a great deal of damage yet, but we’re not sure if they’ll stay in the background forever, either,” Ryckman said.
And so, the battle against aquatic nuisance species continues.
“The trend across the country as ANS problems have gotten more and more severe, particularly Minnesota, is that it’s not going to go away unless agencies get serious about enforcement and get serious about regulating the movement of aquatic nuisance species,” Ryckman said. “Our goal is to have everyone aware of ANS, to understand that this is a serious problem and to make sure they are not the ones responsible for spreading aquatic nuisance species.”
To prevent the spread and transportation of aquatic nuisance species, anglers should also inspect their fishing gear for vegetation before packing up and moving to another body of water.