High water hindering sturgeon-counting project on Rainy River
Persistent high water levels on Rainy Lake and the Rainy River aren’t just a hassle for resorts and anglers this summer. The high water also is hampering fisheries biologists who are conducting a population estimate on sturgeon in the river and Lake of the Woods.
High water carrying debris downstream in in the Rainy River has made it difficult for the biologists to set gill nets in the river, said Phil Talmage, Minnesota Department of Natural Resources area fisheries supervisor at Baudette. Water levels are up primarily due to heavy rains along the international border in June.
In April and May, biologists captured and tagged about 1,300 sturgeon. The fish were released to mix with the rest of the sturgeon population.
Then, starting June 23, the DNR and other agencies began setting nets to recapture sturgeon in the river and on bays of Lake of the Woods. After comparing the number of tagged sturgeon to untagged sturgeon in the recapture effort, biologists can use a formula to estimate the overall sturgeon population.
The Ontario Ministry of Natural Resources and the Rainy River First Nation also are participating in the so-called “mark and recapture” project. The survey is a follow-up to a similar assessment in 2004, which tallied the recovering population at an estimated 60,000 sturgeon 40 inches or longer. By comparison, there were only about 16,000 sturgeon in that size range when the Ontario MNR conducted the first population survey in the late 1980s.
Fisheries officials have been able to set recapture nets in Four Mile Bay and Big Traverse Bay on Lake of the Woods, Talmage said. So far, about 200 sturgeon have been captured this summer, and four of them had been tagged this spring, he said.
“We’re on a better clip than we were last time (2004),” Talmage said. “In the last population estimate, we recaptured six fish. It shows there are a lot of fish out there untagged, which indicates there’s a good abundance of fish.”
Talmage estimated that fisheries crews would be able to set nets in the river in the next few days. As water temperatures rise in mid-summer, however, sturgeon sometimes die in the gill nets. To avoid that, crews would quit netting then and resume in the fall, Talmage said.
“We don’t want to kill sturgeon,” Talmage said.
In all, the recapture effort involves hundreds of net sites on the lake and the river.
“The big thing is, we have to get all of our sites done,” Talmage said. “We’re confident we’ll come out with a real sound estimate of the sturgeon abundance in the system.”
The water level on Rainy Lake remained 32 inches above normal on Thursday, according to the Lake of the Woods Control Board, although the water level has been dropping gradually during the first two weeks of July. Many docks on the lake remain under water, said Mike Williams, a fishing guide from International Falls. The lake is quieter than usual, he said, because so few residents have their boats in the water.