STOCKING SYNDROME: What goes into the thought process?

DAKOTA REPORT; by North Dakota Game and Fish biologist, Doug Leier

salmon stocking 2013

When I go fishing, it almost always involves at least one of my children, sometimes all three of them, and often Mrs. Leier as well.

Anyone who’s fished with children knows the trip is more about helping with bait and knots and tangled line than it is about a stringer of 3-pound walleyes, but now my oldest son has reached the age where he’s pretty much self-sufficient. He can even help his younger siblings on occasion, and his curiosity has advanced from questions about when is snack time coming to fisheries biology and management.

On a recent outing he asked about fish stocking. I get a lot of questions about that at work as well, so thought it would make a good topic for a column.

The North Dakota Game and Fish Department has the capability to stock millions of fish in the state, and there’s a pretty well-defined plan for accomplishing this. Just “dumping in more fish” into a lake or river doesn’t necessarily create more fish, or improve the odds of catching bigger fish in coming years.

Stocking strategy usually involves several factors, including fish habitat, water chemistry, food structure, existing fish populations, winter kill issues, summer runoff potential and more.

Jerry Weigel, supervisor for fisheries production and development for the Game and Fish Department, describes the North Dakota philosophy on stocking fish: “We stock lakes in North Dakota that many other states probably wouldn’t take a second look at,” Weigel said.

In other words, Game and Fish biologists work hard to provide the best possible opportunities given the hand they were dealt. Since North Dakota does not have nearly the number of natural, deep fishing waters as its eastern neighbors, stocking often plays a major role in developing or maintaining opportunities that otherwise would not exist.

In natural lakes and rivers, certain kinds of fish have been present for ages. They have evolved so they can reproduce within the type of habitat the water provides, and have adapted to certain food sources.

Reservoirs or lakes created when rivers or creeks are impounded may provide livable water for fish, but they may not have the type of spawning habitat that allows certain kinds of fish to reproduce. In those cases, stocking is warranted to maintain the fishery. In waters where natural reproduction occurs on a consistent basis, stocking is not necessary.

What has been observed during recent high-water years, is that natural reproduction is occurring even in some of our smaller water bodies. However, during normal or dry conditions, natural reproduction often is limited, so stocking is sometimes necessary to sustain a fishery in the long-term.

Reservoir water levels also change more dramatically than natural waters. What might be good spawning habitat one year could be several feet from the water’s edge the following year. If water levels fall far enough, a reservoir may not be able to support fish life over the winter.

As Weigel points out, “In times of extended drought our challenge is to maintain a solid base of fishing opportunity.”

On the other hand, high water levels can stimulate a fishery. Flooded vegetation is ideal spawning habitat for northern pike and yellow perch, and is also a hideout for small fish of other desirable species like walleye or bass. In the last decade, we’ve seen this high-water phenomenon influence dozens of lakes – both natural and man-made – across the state.

Even in large bodies of water such as Devils Lake and Sakakawea, occasional stocking serves as sort of a safety net, helping to smooth out the peaks and valleys that would otherwise occur naturally.

The bottom line is, fish stocking is not always needed, but some North Dakota lakes would have limited or no fish populations without the Game and Fish Department’s comprehensive stocking program.

Leier is a biologist with the Game and Fish Department. He can be reached by email:


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