Fisheries Management Work and Information

Occasionally, we do survey work on lakes and streams or have recent events that may not show up on the main DNR webpage, or may only show up in our files in Montrose.  Below are a few pieces of the information that we have compiled over the past few years that we thought might be of interest to anglers as well as lake property owners.  Please feel free to contact any one of our staff in Montrose if you have further questions.

Muskellunge Management on Sugar Lake

Sugar Lake 50 inch MUE

Sugar Lake is a highly developed, 1,015-acre recreational lake located five miles north of Maple Lake, MN in Wright County.  In 1967 Sugar Lake was designated for muskellunge management.  Sugar Lake was chosen as a muskellunge lake because of its large size and good water clarity.  The fast growing Mississippi Strain of muskellunge fingerlings had been stocked annually from 1989 to 2004.  Since then stocking has been reduced to ever other year.

In Minnesota, the management goal for muskellunge is to have a low-density (0.2 - 0.4 adults/acre) population of high quality (larger) individuals.  Benchmarks for measuring these population goals are spring trap net surveys and population estimates.  In 2007, the first every population estimate was conducted on Sugar Lake.  April trap netting followed by night electrofishing produced an estimate of 0.26 adults (> 30")/acre.  While crude, it means that the total population is probably around 600 adult fish.  In 2012, the population estimate was repeated using the same techniques and produced an estimate of 0.22 adults (> 30")/acre very similar to 2007.

When Minnesota raised the statewide minimum size limit of muskellunge to 40 inches in 1993, smaller fish were conserved and this helped increase the overall size structure of the muskellunge population.  In 2007, the statewide minimum size limit was increased to 48 inches further increasing the overall size structure of the population.  Based on size structure indices, the Sugar Lake muskie population continues to grow and the average size has increased for the fourth survey in a row (see table below).

 

Year

RSD38

RSD42

RSD50

Average TL

(in)

 2012  87 57 2  42.4
 2007  84 37 2 41.0
 2003  62 42 0 39.0
 1998  48 21 0 37.0

 

Size structure indices such as relative stock density (RSD) is the percentage of muskellunge sampled that are longer than 20 inches and are also longer than a specified length.  For Sugar Lake we were interested in the percentage of fish longer than 38 inches (RSD38), 42 inches (RSD42), and 50 inches (RSD50), respectively.  For example, in 2012, 87% of the muskellunge sampled that were longer than 20 inches were also longer than 38 inches.  This was the second survey in a row that we have seen fish over 50 inches.  The first reported angler caught 50-inch fish was in 2005.

Sometimes muskellunge are the victims of controversy and Sugar Lake was no exception.  So, we conducted creel surveys in 1984 and 1998.  Over the years, one of the biggest changes was the number of anglers seeking muskellunge.  Twenty-nine percent of angling parties sought muskellunge in 1998 vs only three percent in 1984.  During the 1998 survey, lake residents were asked - "Do you support muskellunge management?" 68% indicated support (87 of 140 respondents).

Improvements are still needed in the overall fishery of Sugar Lake.  A large population of small northern pike is still impacting the fishery.  In 2007, the northern pike population was estimated to be 15,000 adults.  To help manage the northern pike population, new regulations were placed on Sugar Lake in 2007.  The current regulation is a 24 - 36 inch protected slot, with only one fish over 36 inches allowed in possession.  It is hoped that the size structure of northern pike will improve, that anglers will enjoy quality northern pike angling, and that the entire fish community will be brought into balance.

Walleye Fry Stocking in Buffalo Lake

 Walleye Fry

Buffalo Lake is located within the city limit of Buffalo, MN, in Wright County.  Buffalo Lake is hypereutrophic, windswept, does not stratify in the summer, and does not winterkill.  Until 1980, Buffalo Lake received the wastewater effluent from the municipal treatment plant.  Partly because of this, the lake experiences large nuisance algal blooms.  In recent years however, the lake has been showing signs of restoring itself.

The history of walleye stocking in Buffalo Lake dates back to the 1940's.  During the early 1980's walleye fingerlings were stocked at a rate of one pound per littoral (area < 15' in depth) acre every other year.  Then in 1984, fry stocking was tried (1,000 fry/littoral acre).  Walleye fry are small fish that are just hatched and are about the size of mosquito larvae.  The 1988 assessment showed stocking to be successful and the lake has been stocked with fry exclusively ever since.  The management strategy is to stock walleye fry every other year.

In the four surveys conducted since 1988, the gill net catch has been above the third quartile value (6.3/gill net) for similar lakes.  A creel survey conducted in 2002-2003 estimated that 8,244 adult walleye were harvested, making it the top producer in the state compared to similar lakes.

The reason the DNR stocks walleye is that there is little natural reproduction of this species in south central Minnesota.  This may be due to lack of suitable spawning habitat, competition or predation by other species or other factors.  Walleye may try to spawn, but few fry survive; or some adults will just re-absorb their eggs.

The advantage of stocking fry is that it is cheaper and often produces a stronger year-class whereas, fingerling stocking is more expensive, are sometimes not available, and usually only produce weak to moderate year-classes.  Comparing costs: 1,500 lbs of fingerlings @20/lb would cost $10,000; and 1.5 million fry would cost $1,500.  Some other examples of successful fry stocking are Cedar Island and Horseshoe Lakes in Stearns County and Clearwater Lake in Wright and Stearns Counties.

Considerations for Crappie in area lakes

Research and observations show that crappies do not spawn successfully each year. That is good because populations usually won't become abundant and stunted as do sunfish. It is bad in that population numbers sometimes become low and fishing success is diminished.

Crappies thrive in lakes with poor water clarity. Local examples are French, Constance, and Dog Lakes. Whereas, crappies generally are not abundant in lakes with good water quality. In clear water lakes, crappie populations tend to be low but the average size can be quite good. Examples include Sylvia, Pulaski, and Sugar.

Because crappie have variable recruitment, stocking probably will not help the population. Most lakes contain a sufficient number of brood fish (only one pair per ten acres is needed) for natural reproduction. The average number of eggs per 7.5-9" female is 38,000.

Recent studies have shown that crappies select nesting sites on undeveloped lake shorelines where emergent vegetation, especially bulrush is present. Restorative actions and naturalizing shorelines will help provide habitat for crappies and thus increase their spawning success.

Angling can affect crappie populations. At Lake Pulaski anglers harvested 33% of the years harvest in May and June of 2003. At the Horseshoe Chain, about 33% of the open water harvest occurred in May and June (1999).

Anglers generally do not release large crappies. At Mink and Somers Lakes (Winter 2002) anglers harvested nearly every crappie caught with harvested fish averaging 10 inches in length.

Posting spawning areas so as to restrict fishing will not improve crappie populations. In the above examples approximately 33% of the population might be saved if the season were closed during May-June. To post a smaller area of a lake would result in less of a savings, and then only for a time. The survivors might be harvested during a later season.

At Buffalo Lake, Wright County, only 3% of the annual harvest took place during May-June (2003). Sixty one percent of the harvest took place during the winter.

Special fishing regulations might help improve the size structure of crappie populations. A five fish daily bag will decrease harvest; while a 10-inch minimum size limit will improve the overall size structure. Alternatively, we have the option of closing the harvest season from March 1 - July 1. All of these regulation options would need considerable public support.

In many lakes, crappie suspend over deeper water in mid-summer and can be hard to catch. Spring and winter are times when anglers can enjoy good fishing. We do not want to limit good angling opportunities for crappies if there were no good biological reason to do so.

Illegal harvest of crappies is frequent and harms the resource. In a recent incident (2005) at Long Lake in Stearns County 10 tickets were issued in a short time for over-limits and double tripping. Call the conservation officer if you observe illegal activity.

Mink and Somers Lake Restoration

Mink Lake NOP

Mink andSomers Lakes are located four miles north of Maple Lake, MN in Wright County and are connected by a navigable channel.  Mink Lake is 301 acres and has a maximum depth of 39 feet whereas, Somers Lake is 158 acres and has a maximum depth of 21 feet.

Until 1994 there had been a history of periodic winterkill and restocking.  Winterkill events occurred on average once every five years and were usually partial in nature.  Winterkills occurred in 1986,1988 and 1991-92.  Winterkill severity was exacerbated by low water conditions, which occurred during the drought of 1988-89.  A 1992 test netting showed carp to be present and were caught at a rate of 35/gill net, seven times the expected catch.

The lake association decided to ask the DNR to reclaim the lakes.  Reclamation means that the lakes are treated with rotenone to kill off the existing fish populations.  The treatment was successful and game fish were restocked.  Special regulations were then applied to the developing fishery.  The current regulations for Mink and Somers Lakes are: Sunfish: possession limit 5. Crappie: possession limit 5. Walleye: 17-inch minimum size limit, possession limit 3. Largemouth Bass: 12 - 20 inch protected slot, one fish over 20 inches allowed in possession. Northern Pike: 24 - 36 inch protected slot, one fish over 36 inches allowed in possession.  Live minnows are prohibited in order to prevent the re-introduction of undesirable species (especially bullheads).

The project has been an overwhelming success.  Lake association members and the community have supported the regulations.  In 2006, 12 years after the treatment, catches of all species were above expected levels when compared to similar lakes.  The lakes have become destinations for bass anglers.  DNR electrofishing catch rates for largemouth bass were over a hundred per hour.  More than 40% of all northern pike were larger than 24 inches and in 2002-03, 40% of the sunfish were larger than eight inches.

Because of relatively poor water quality, aquatic plants and algae grow in nuisance abundance.  The fishing success will depend somewhat on future in-lake conditions.  But results so far lead us to believe that exceptional angling will continue, though maybe not for all species all the time.  The fishery is much improved over what previously existed before treatment.  For the current status of the fishery go to LakeFinder and search for Mink or Somers Lake.

Improving Access to Rivers

Riverside Access

Minnesota's warm water rivers are underutilized in terms of recreation and angling.  Part of the reason may be that it is often difficult to obtain access.  But access to the North Fork of the Crow River just got easier when the DNR construction crew improved several sites on property owned by Wright County.

The fishery of the North Fork of the Crow River is typical of fisheries in southern Minnesota's warm water rivers.  Shorthead redhorse were the most abundant fish in the most recent survey.  However, game fish such as channel catfish, smallmouth bass, walleye, bluegill, and northern pike are all present in fishable numbers.

In 2001, the fisheries construction crew based out of Detroit Lakes improved the access at three sites: Riverside Park (pictured above), Crow Springs County Park, and Betty Mason Wayside.  The steep grade of the riverbanks was cut back, the approach was graveled, and streamside vegetation was restored.

There are nine access sites to the North Fork of the Crow River and since it is one of Minnesota's water trails, photos of all the access sites, map locators, and description of canoeing and fishing opportunities can be found under Crow River Access Guide.

Trout Stream Access and Habitat Improvement

Luxemburg creek is a cold-water stream that was designated as a trout stream in 1951.  Its headwater is located approximately 1.5 miles southwest of Luxemburg, MN, in Stearns County and flows approximately six miles to the confluence with Johnson Creek.

Since the initial survey in 1949, the stream has been noted for its natural reproduction of brown trout.  Anglers occasionally report brown trout up to 24 inches.  That is a big fish for a small stream that averages 10 feet in width.

The DNR acquired its first easements along a 1,400-foot area within the residential development known as Cherrywood Estates and creek Side Addition.  Additional easements between the mouth and the lower end of the existing easement were acquired in 2004.

In the summer if 2001, root wads were placed at 30o angles facing upstream along four bends in the creek to stabilize the bank, minimize stream velocity, and offer overhead cover.  The most positive results occurred in 2006 when it was discovered that the catch of brown trout was substantially higher than in previous years.  A total of 84 brown trout between four and 16 inches were sampled. The complete report as well as reports from other trout stream in our area and access maps can be found at the following link Stream Surveys.