Part II: Two important Minnesota natives call Kettle River home
Last week, readers got to know the Kettle River and its watershed. This week, we'll look at two of the river's more unusual residents: lake sturgeon and wild rice. Monitoring work and projects in the watershed, done by the Carlton County Soil and Water Conservation District (SWCD) and other organizations, will help to protect and preserve the watershed's clean water and greatly benefit these two popular residents.
Lake sturgeon are one of 34 species of fish that the Minnesota Department of Natural Resources (DNR) found during a 2002 survey of the Kettle River.
"The Kettle River is an important resource to Minnesota fisheries as it is one of few rivers where lake sturgeon live and spawn," said SWCD manager Brad Matlack.
Lake sturgeon, Acipenser fulvescens, are very special fish. One of the oldest species on earth, they still look like their dinosaur ancestors. Sturgeon are also one of the longest-living freshwater fish in the world; the oldest one on record was 152 years old. They are also the largest fish in the Great Lakes with some having grown to nine feet long and weighing over 300 pounds. In fact, the largest fish ever caught in Minnesota was a 70 inch, 94-pound lake sturgeon caught in 1994 in the Kettle River. That's a lot of "records" for one fish!
Living in both lakes and rivers, at one time sturgeon were found throughout the Great Lakes, Hudson Bay and Mississippi River basins from Canada to Alabama. However, by the early 1900s, lake sturgeon populations were severely decimated due to pollution, dams and overfishing. Lake sturgeon were popular gamefish not only because of their size and looks, but also because of their delicious meat and eggs (caviar).
Because of this popularity, the Minnesota DNR paid attention in the early 1990s when fishermen reported catching considerably fewer lake sturgeon in the area, particularly in the Kettle River. Thus, in 1992, Hinckley DNR fisheries personnel started tagging lake sturgeon in the Kettle River, not only to assess the population, but also to acquire much needed information about the life of sturgeon in the river system.
In 2003, after 11 years of tagging, fisheries personnel discovered interesting information about 571 lake sturgeon, of which 370 were recaptured two or more times. The largest number (439) of those fish were caught in the Kettle River. The largest sturgeon caught was 63.5 inches long and weighed 56 pounds, and the oldest was 43 years old. The tagging process also gave biologists information about how fast lake sturgeon grow in length and weight, how they migrate, their estimated population size, what condition the fish were in, and more.
Biologists were very surprised to find that the lake sturgeon population in the Kettle River is a resident, year-round population, which is very unique as most sturgeon live in the lake and only return to the river to spawn. Although there are no physical barriers between the Kettle and St. Croix rivers, most of these sturgeon appear to stay in the Kettle River the entire year. They also migrate between systems as one lake sturgeon that was originally tagged in the Kettle River was also caught on the St. Croix River.
Besides moving downstream, lake sturgeon also move upstream, as noted by studies after the 1995 removal of the old Sandstone dam. The dam removal unfortunately released years of accumulated sediment that covered known spawning sites and filled in important deep pools. However, the removal also opened the entire range of the Kettle River to sturgeon which were previously restricted by the dam.
Recent evidence of lake sturgeon migrating upstream came from one of last year's greatest fishing stories. On June 26, 2016, Barnum's Dale Smith caught a whopper of lake sturgeon on Big Hanging Horn Lake. The trophy fish was 59 inches long and weighed 50 pounds, just shy of the Minnesota record! It was a wonderful surprise for everyone to find a lake sturgeon that far upriver in the Kettle River system.
According to Hinckley's DNR fisheries website, the outlook for lake sturgeon in the Kettle River looks bright due to cleaner water, regulated harvest, and more access to habitat. Although it will take decades more to bring lake sturgeon back to the historic numbers seen decades ago, the website notes: "If things go right, our grandchildren may have a chance to actually catch a 100-pound sturgeon instead of just seeing old pictures."
MINNESOTA'S STATE GRAIN
The other unusual resident in the Kettle River watershed is wild rice, "Zizania aquatica," an annual water-grass seed that is Minnesota's official state grain. Besides being good human food and providing needed habitat for waterfowl and birds, wild rice provides high-quality, high protein food, especially for "refueling" waterfowl during fall migrations.
In past years, many of our northern lakes grew abundant wild rice. Recent years, though, have found the plants starting to disappear from more area lakes and rivers.
There are several good wild rice growing areas in Carlton County.
However, Jacob Granfors, a biologist with Pheasants Forever and Quail Forever, has only found two areas in the Kettle River Watershed with prime wild rice stands. One is the Kettle Lake southeast of Cromwell near the head of the Kettle River. The other is the Moosehorn River south of Moose Lake where the river widens on its way to Pine County. Working through a grant acquired by Carlton and Aitkin SWCDs, Granfors is identifying and acquiring easements to protect and preserve prime wild rice stands. So far, two private property easements on the Moosehorn have been enrolled to protect a total of 43.75 acres and 5,000 feet of riverfront.
Why is wild rice so special and in need of protection? For several reasons actually.
First, wild rice only grows in northern lakes, marshes or streams, and the plants need calm, clear water six inches to three feet deep. If the water is too deep, the sun's rays cannot reach the seed during germination. If the water is too shallow, the plant develops a weak stem.
Second, wild rice needs a consistent water depth, especially during the spring after germination when roots are anchoring the seedling plant. During this critical time, if the water level rises, the stalk is pulled up as it is still too weakly rooted. And if the water level drops, the stalk can collapse as it is still too weak.
Third, during August, if the temperatures and humidity levels are both very high at the same time, it can create ideal conditions for the Helminthosporium disease that can wipe out a wild rice stand in a matter of days.
Fourth, during the September harvest, if a frost occurs, the crop is lost. And if a storm with winds comes up, the rice can easily "shatter" and fall immediately to the ground or water. A whole crop can be wiped out within a day from either of these weather occurrences.
Finally, if a wild rice crop makes it from germination to harvest, the wild rice yield is meager compared to traditional white rice. While white rice harvests yield 4,000 to 6,000 pounds per acre, wild rice only yields 100 to 200 pounds per acre.
All of this makes wild rice a very special and valuable crop for northern Minnesota, one that the Carlton County SWCD is working with landowners to preserve and protect.