While North Dakota is more than holding its own in a nationwide resistance effort against aquatic nuisance species, the fight to limit the introduction and spread of exotics in the state is ongoing.
In 2013, Game and Fish Department staff monitored nearly half of the state’s record 400-plus waters, turning up just one new infestation – curly leaf pondweed in Grass Lake in Richland County.
According to fisheries division reports, the state’s most expansive nuisance in terms of recent documented infestations is curly leaf pondweed, which is found in about a dozen waters, while Eurasian water milfoil is found in just two. Greg Power, Department fisheries chief, said that known ANS infestations are, overall, generally stable or appear to be in decline.
Fred Ryckman, Department fisheries supervisor, said fisheries staff again found a few adult silver carp in the James River in 2013. These exotics made their way into the North Dakota portion of the James during extremely high flows in 2011.
“There are some adults still in the river, but there is no sign as of yet of reproduction or recruitment,” Ryckman. “This small group of adult fish is maturing and will likely release eggs, but whether the eggs will hatch is unknown. I don’t think the James River is good habitat for silver carp reproduction, but we don’t know that for a fact at this point.”
In 2013, for the second year in a row, zebra mussels were not found in the Otter Tail and Red rivers at Wahpeton, where immature mussels were first detected in 2010 and then again in 2011. Unfortunately, adult zebra mussels have become established in Minnesota’s Otter Tail River, and have been documented by the Minnesota Department of Natural Resources to have moved farther downstream and closer to North Dakota in the past few years.
Curly leaf pondweed is the state’s most expansive aquatic nuisance species.
In fall 2013, adult zebra mussels were discovered in Lake Winnipeg, which means the mussels are now found both downstream and upstream of the Red River in North Dakota.
“When mussels were discovered in Lake Winnipeg, our fisheries guys spent a lot of time on the Red looking for adult zebra mussels, but found none,” Power said. “The bottom line is the Red River remains free of adult zebra mussels. The future looks cloudy, however.”
Game and Fish Department biologists speculate on why the Red River in North Dakota has thus far dodged the adult zebra mussel bullet. “Maybe the tipping point that makes it difficult for adult zebra mussels to become establish in the Red is the water chemistry,” Power said. “Maybe the water chemistry and sediment load varies just enough that the environment is too hostile. Time will tell.”
The list of ANS that fisheries personnel are on the lookout for in North Dakota is not terribly long, but new exotics have been added over time. Last year, fisheries personnel and others made a special effort to determine whether rusty crayfish were present in North Dakota waters.
“To the best of our knowledge, we have just two species of crayfish in North Dakota and the rusty crayfish isn’t one of them,” Power said.
Department fisheries staff collected crayfish from North Dakota lakes during fish sampling efforts in 2013, while Valley City State University staff and students sampled rivers and streams.
“This intensive sampling effort provided a good representative sample of crayfish from around the state,” Power said. “And, thankfully, our previous belief that rusty crayfish don’t exist in the state was confirmed.”
According to Minnesota Sea Grant, rusty crayfish have invaded much of Minnesota, Wisconsin, Michigan, Illinois, Ontario, and portions of 17 other states. This invasive species is believed to outcompete native crayfish, and decrease the density and variety of aquatic invertebrates and plants.
Wildlife officials believe that rusty crayfish were introduced into unfamiliar waters in Minnesota and elsewhere by anglers using the exotics as bait.
Because North Dakota is a destination for nonresident hunters, anglers, boaters and other outdoor enthusiasts who hail from states with ANS problems, the threat of aquatic nuisance species hitching a ride into the state remains a legitimate concern.
Understanding this, the Game and Fish Department’s warden force has redirected time and resources, especially in eastern North Dakota, to patrol for exotic species that could come into the state on boats, trailers and other outdoor equipment.
“Protecting the state from ANS is definitely a priority, and we have and will continue to redirect time and manpower to this,” said Robert Timian, Department enforcement division chief. “The challenge is determining the amount of time and manpower to dedicate to ANS. ”
In 2013, more than 30 ANS violations were reported in North Dakota as compared to just a dozen in 2012.
While educating people on the fallout of aquatic nuisance species infestations, which the Game and Fish Department has been doing for more than a decade, is important, Ryckman said enforcement is critical to keeping North Dakota relatively free of invading pests.
“When it comes to obeying ANS regulations, there are some people out there who know better, but refuse to do the right thing,” Ryckman said. “We need to make sure that we have really good compliance, not just ho-hum compliance.”
ANS lake sampling by year:
|Year||# of waters sampled|