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The days continue to add minutes of sunlight, the spring turkey application deadline is past and, before you know it, spring open-water fishing will be the hot topic.

Todd Caspers, a North Dakota Game and Fish Department Devils Lake fisheries biologist, notes that some anglers express concern that too many large walleye are caught in spring, when runoff is high at Devils Lake. Many worry that the result may lead to poor walleye reproduction.

Biological perspective

Biologists monitor the Devils Lake walleye population annually to determine if any conditions exist that would warrant a special regulation, such as a maximum length limit, or the commonly requested “one-over” limit.

Spring fishing in the upper Devils Lake basin was very good from 2009-13. In spite of this harvest, three of the five largest year-classes ever were produced during this period, with the largest documented at Devils Lake in 2009.

Additionally, in 2012 the percentage of walleye longer than 15 inches was well below average, yet the second largest year-class ever was produced that year. This is pretty good evidence that the hooking of spring walleye in the upper basin coulees has not limited reproduction.

At Devils Lake in recent years, the total walleye mortality rate, has been below what biologists across North America consider the normal range of about 40 percent to 55 percent.

Additionally, specific to Devils Lake proper, creel surveys indicate that anglers harvest large walleye at a lower rate than smaller fish. For example, test netting in 2013 showed that walleye longer than 20 inches made up more than 9 percent of the Devils Lake walleye population.

However, during a creel survey that summer, only about 3 percent of the fish that anglers caught and kept were longer than 20 inches, indicating that either these large walleye were harder to catch or perhaps anglers were more likely to release them. Similarly, during the summer of 2016, walleyes more than 20 inches made up about 8 percent of the walleye population, but only 3 percent anglers' catch.

Moving forward

With all this scientific research and angler activity surveys to draw upon, Game and Fish biologists are confident the current Devils Lake basin walleye population does not meet the biological criteria that would warrant a maximum length-type-limit to protect fish for spawning. Any new maximum length or “one-over” regulation would needlessly restrict angler opportunities and would not benefit the walleye population or anglers.

Doug Leier is a biologist for the Game and Fish Department.

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