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The original item was published from 12/21/2015 6:14:27 PM to 1/21/2016 12:00:03 AM.

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Natural Resources

Posted on: December 23, 2015

[ARCHIVED] Gamefish are not just for Eating

Promoting a healthy and balanced fish community can lead to better water quality in local lakes. Follow the link to learn how…

Have you ever heard of a top-down fish effect to improve lake water quality? This project is accomplished in two ways, top predator fish are added to a lake or conditions are tweaked in a lake to improve predator fish survival.

Here is how top-down fish effect typically works. First, you have a lake with a big algae problem; lakes that turn pea soup green in the summer from blue-green algae are good candidates. The lake is likely missing top predator fish like bass, walleyes, or channel catfish. With the absence of game fish there can be too many rough fish like carp, bullheads, and minnows creating a host of problems. Rough fish tend to root in the bottom of lakes when food is scarce which results in worse water quality. The bottom soils of a lake contain high amounts of phosphorus that are stirred up in the water leading to more algae growth. Uprooting of native aquatic plants that act like a filter in the water and reduce sediment resuspension on windy days is another issue. The lack of game fish can lead to a shift in the food chain where small critters that feed on algae are much lower in population (more algae grazers = clearer water). Add game fish and voilà, they eat the rough fish and change the food chain so there are more algae grazers.

Sound simple? Are you wondering why all the lakes are not crystal clear if it only takes a couple of walleye? Well, there is a bit more to it. Several lakes did not have game fish because the lake could not support them. Regular restocking and additional measures like winter aeration are required to see continual top down fish effects. In many cases, the magnitude of phosphorus pollution in the lake causes algae growth too great to be helped by game fish stocking alone. These are a few of the complicating factors.

That said, managing the fish population in a lake can be a key tool in suppressing algae blooms.

Learn More About Lake Aeration Here…
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