From wildlife clubs and advisory board meetings to conversation at a local coffee shop, it's obvious that North Dakota anglers want to see their favorite fishery improve.
No matter how good those fisheries are, ideas to make things better frequently come to the forefront, whether the subject of interest is big waters like Sakakawea or Devils Lake, or regional destinations like Bowman-Haley Reservoir in the southwest or Homme Dam in the northeast.
But improving a fishery is seldom an easy objective. Stocking more fish is not usually the answer, and sometimes, stocking fewer or no fish is the best solution to achieve long-term results.
Reduced or increased daily limits, and fish size restrictions also are possible options for addressing fish population structures. Let's take a closer look at some of the often-suggested management actions to see when and where they are best applied.
Among the changes included in the 2008-10 fishing regulations was elimination of a few fish size restrictions North Dakota has had in place for years. Specifically, the 14-inch minimum size restriction for walleye on Lake Elsie, Brewer Lake and Dead Colt Creek Dam were taken out, as well as both walleye and northern pike size restrictions for Sprague Lake and Lake Tewaukon. These size restrictions were first put in place in 1994.
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An ongoing Game and Fish Department philosophy is to remove regulations that are no longer needed or haven't served their intended purpose. While that was the case for the above-mentioned lakes in southeastern North Dakota, the state still maintains a number of lake/river-specific size restrictions that involve walleye, northern pike, largemouth bass and catfish. North Dakota also has one statewide minimum length for musky.
Each of these continuing regulations serves a defined purpose that is still functioning. The other side of that philosophy is that before any new regulation is put in place, it has to address a valid concern and have a reasonable chance of succeeding.
Over the past several years, Game and Fish biologists have received considerable input from anglers regarding possible fish size restrictions on any number of waters, but most often related to walleyes in Devils Lake, Lake Sakakawea and the Missouri River downstream of Garrison Dam. Under the right circumstances, size limits can work, but many also fail.
Minimum size limits are designed to reduce harvest of small fish, allowing more fish to reach a desirable size. A minimum size limit works when there is high angling mortality, when natural mortality is low, when reproduction is low, and when fish growth is relatively good. If a fish population doesn't meet the above criteria, a minimum size limit can harm the population. For example, if that population exhibits slow growth, fish may get harvested as soon as they reach the legal length and population size structure may shift to too many fish just below the legal length, resulting in a stunted population.
In recent years, the department has received a fair number of inquiries regarding the need for some type of size regulation for walleye in the Missouri River below Garrison Dam and Devils Lake. Fisheries biologists routinely collect growth, recruitment and mortality information on these walleye populations to ensure that appropriate regulations are in place for the health of these fisheries and to provide a quality angling opportunity.
The information collected helps fishery managers determine if benefits could be realized from length restrictions. The Missouri River walleye population meets two of the criteria -- good growth and low natural mortality -- but does not meet the other two criteria -- low reproductive or stocking success and high angling mortality.
Applying a minimum length limit to this fish population would needlessly restrict angler harvest. A minimum length limit could even negatively impact this walleye population by increasing competition for food among small fish, which may ultimately decrease growth and increase natural mortality.
No doubt many North Dakota fishing waters will benefit this year from rising water that floods vegetation and increases habitat. Remember, fisheries generally take a couple of years, but the stage is set for improved fishing in years to come.
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Leier is a biologist with the Game and Fish Department, he can be reached by e-mail at dleier@nd.gov . Read his blog daily at www.areavoices.com/dougleier .
