Building Fish Habitat

January 20, 2010 by  

By Doug Leier

More than 40 years ago the North Dakota Game and Fish Department, in an effort to create structure for fish and create artificial habitat within Heart Butte Dam (Lake Tschida) in Grant County, sunk some old car bodies into the reservoir.

As you might expect, the practice of using car bodies for building fish habitat was short-lived, but the need for creating habitat in some waters did not go away. Eventually, discarded Christmas trees became a more natural and available element for adding to lakes that needed additional spawning and escape structure.

Building fish habitat can produce healthier fish to enjoy again and again.

Building fish habitat can produce healthier fish to enjoy again and again.

Over a couple of decades numerous North Dakota lakes including Elsie, Spiritwood, Williams and Moon in the southeastern part of the state, and even larger reservoirs such as Audubon, Lake Ashtabula, Pipestem and Jamestown Reservoirs, got artificial reefs in an effort to boost fisheries production during a time of prevalent drought. Since then, as the state recovered from drought starting in the mid-1990s and numerous new lakes were created from flooded wetlands, use of artificial reefs has been scaled back.

Construction of these projects is time-consuming for Game and Fish staff and local wildlife and fishing club members who volunteered thousands of hours for reef projects at their local lakes.

Research on those projects showed the effort was generally worthwhile but results were often short-term. Many artificial habitat reefs enhanced fishing and/or natural reproduction of sport and forage fish, as well as provided cover for 10 or more years. Depending on the lake, however, artificial reefs may not provide any benefits, and they are not a quick fix in lakes where benefits would occur.

And, experiences over the last 10 years emphasize that natural fish habitat – a combination of water and plants, bottom structure and depth – is more productive than artificially placed  habitat. However, some bodies of water have little structure, and adding artificial habitat may be the only way to enhance a fishery in the long term.

Periodically I get questions about the old Game and Fish tree reef program, and thought it might be beneficial to looking at the issue from a couple of different angles.

Artificial reefs can attract fish and therefore increase angling success in areas where fishing is poor, even though fish populations are healthy.

Tree reefs can provide spawning habitat or escape cover, not only for game fish like perch and crappie, but also for forage fish like fathead minnows.

Artificial reefs are ideal projects to involve local anglers or wildlife club members in an effort designed to yield local benefits and/or ownership.

We caught many crappies over beds of Christmas trees in the wintertime, great stucture for crappies

We caught many crappies over beds of Christmas trees in the wintertime, great stucture for crappies

And here’s a few other considerations:

Artificial reefs are labor intensive and benefits are not always predictable.

If artificial habitats are placed in lakes where they are not needed, they could increase fish production to the point of overpopulation for some species.

If water levels recede in lakes where artificial reefs exist, exposing the trees or tires, the material is unsightly. Reef-tops could also become boating hazards.

If a reef works in one area, public perception is that it will work in all areas. People may assemble and install reefs without Department approval if they think it will help their lake, or they may,with good intentions, leave Christmas trees on a lake on their own.
Citizens who construct reefs on their own, or leave trees on frozen lakes (where the tree will wind up on shore after the ice goes out) could be subject to a littering violation. These situations are easily avoided by involving a local fisheries biologist in any prospective reef project.

Like many of you, I’d enjoy more fish and bigger fish. But the reality of establishing habitat is similar to that of stocking of fish — it’s not as simple as dumping fish or trees into a lake and hoping for the best.

We’re better served to assess the potential of each individual fishery and apply the best possible recipe for maintaining and enhancing its potential.

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


One Comment on "Building Fish Habitat"

  1. alvin on Fri, 14th Nov 2014 7:08 am 

    how can contact you guys?

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