Fishing opportunities in two of the heaviest fished lakes in Stutsman County might deteriorate this summer due to winter fish kills, according to B.J. Kratz, district fisheries supervisor for the southeast region of the North Dakota Game and Fish Department.
"Basically, since mid-January we've been getting low dissolved oxygen readings," he said. "... we've checked close to 50 lakes in the southeast district. Eighteen lakes have concerns but are not necessarily deal breakers. Nine are in serious condition."
Lakes in serious condition include those at Pipestem and Jamestown dams as well as Casselton Reservoir, Crystal Springs, Gaier Lake, Flood Lake, Kulm-Edgeley Dam, N. Woodhaven, Sunday Lake and TAD Lake.
Dissolved oxygen is necessary for fish to survive. Kratz said a long winter with a heavy cover of snow over the ice has depleted the reserves of oxygen in some lakes.
"The amount of snow is a factor," he said. Heavy snow restricts light penetration into the water which limits oxygen-producing photosynthesis. "The length of the winter is another major factor. We had an early winter and a late spring."
Kratz said the level of fish kill in the listed lakes is still speculation based on oxygen measurements. The actual amount of fish kill won't be known until the ice is out and biologists get on the lakes to look for accumulations of dead fish.
Still, in some lakes, the outlook is bleak.
"Kulm-Edgeley Dam could be total kill," he said. "But you never can be sure."
The outlook for the lake behind Pipestem Dam is also dire, Kratz said.
"Our last major winter kill there was in 2012," Kratz said. "The readings this year are worse than then."
Kratz said the 2012 fish kill "obliviated" walleye and perch populations and hurt the northern pike at Pipestem. In the six years since, Game and Fish has been stocking Pipestem in an effort to rebuild the population. But the current winter kill situation may set that back.
"The perch and walleye fishing is collapsing," he said. "We could also see a possible loss of a fair amount of the crappie population."
The problems could also extend to the lake behind Jamestown Dam.
"Jamestown Dam has a similar situation but possibly not as severe," Kratz said. "It (the oxygen level) is low enough to cause loss of fish life."
Dan Widmer, a member of Dakota Anglers who helps organize fishing tournaments, said the loss of fish numbers will have a big impact on the fishing public in the area.
"If it's just carp and bullheads it's no big deal," he said. "If it is the other fish, it will take awhile for the lake to come back."
Widmer said fishing on Pipestem had been good at times last year.
"There were a lot of boats out there if the fish were biting," he said.
Kratz said once the ice goes out of the lakes, wave action and new water running in from streams will replenish the oxygen supply in the lakes. Any fish surviving to this point are likely past the danger point.
"In the course of a week we can go from almost no oxygen to a saturation," he said. "Things are improving."
The Game and Fish Department is anticipating receiving reports of dead fish on any number of lakes this spring. There are about 150 lakes in the southeast region and Game and Fish officials only checked oxygen levels in about 50. Once those incidents are evaluated, they will know the extent of the fish kill in the region, Kratz said.
He does anticipate that the waters behind Pipestem and Jamestown dams will see fish losses.
"The two principle fisheries around Jamestown could be interesting," Kratz said.