Asian carp concern grows in southwest
Windom, Minn. — Asian carp “very easily” could be in waters in southern Minnesota, the result of their discovery in Iowa border waters.
That’s the assessment of Ryan Doorenbos, the DNR’s area fisheries supervisor in Windom, who said, “We’re in the process of looking at it right now.”
According to the Iowa DNR, a commercial fishing company caught 55 silver carp and 82 bighead carp during netting on East Okoboji Lake in late March. The same commercial fisherman caught a silver carp on Spirit Lake in early April.
East Okoboji is just south of Spirit Lake.
While the main part of Spirit Lake is in Iowa, it connects on the western side with Little Spirit Lake, the majority of which is in Minnesota. There is a grate system between the two lakes, but there are 2-inch spaces between the grates, Doorenbos said.
“It’s not what I would call a 100 percent barrier,” he said.
And on the north side of Big Spirit Lake is a channel that leads into Loon Lake, a 707-acre lake in Jackson County. There’s a grate system on the Iowa side of the channel with just more than one-inch spaces, Doorenbos said.
There’s a possibility of beefing up the barrier between Spirit Lake and Loon Lake, said Doorenbos, who also was out last week surveying Loon Lake’s outlets.
The primary risk in Minnesota is the fish getting into the Little Sioux Watershed, Doorenbos said.
“Provided we don’t have 20 inches of rain, they would be isolated to the Little Sioux basin,” he said.
DNR Fisheries staff throughout the southwest are looking at the potential pathways migrating Asian carp could take, according to Dirk Peterson, Fisheries chief. They’re evaluating where pinch points exist, for example, and where barriers could be enhanced.
“Every identifiable pathway is a concern,” Peterson said. “Once we have them, it will be extremely difficult to get rid of them, if that’s even possible.”
Doorenbos said the Iowa DNR is looking at putting a barrier at the outlet of the Iowa Great Lakes. That would be at the Lower Gar Lake outlet, near Milford.
“We are working to get the barrier in place as quickly as possible, but there is a process to this and we need to do it right,” Mike Hawkins, a fisheries biologist for the Iowa DNR, said in an agency news release.
Doorenbos expects that barrier to be complete by this fall or next spring. He and his staff also have identified another potential pathway for Asian carp to get into Minnesota: the Rock River. That southwestern Minnesota river connects with the Big Sioux River, which connects with the Missouri River.
There is a barrier on the Rock River – a seven-foot low-head dam in Rock Rapids, Iowa – but during a flood event, “those fish would giggle at that being a barrier,” Doorenbos said.