Harvesting as a Water-Quality strategy
This is a bit of the story of how I came to understand that harvesting as a water quality strategy just may be the number one strategy for managing eutrophic and hyper-eutrophic lakes.
Originally, Fish Fry Lake was a nutrient-rich, pea-soup green mosquito factory. You would not let your dog drink from the edge. The place stank, and when our black dog did decide to cool off and take a dip, within minutes of coming out of the water his coat would take on a reddish hue. A visiting professor who studies biofilm described the phenomenon as cyanobacteria…which can poison water.
The lake was in such tough shape because agricultural fertilizers were perking into the ground water that in turn perked into the lake. And there was no way for me to prevent this from continuing to happen. I have no control over how folks farm up watershed. So I wrote off the idea of prevention.
There had to be another way. Experts said “aeration” was an answer. So I tried it, and it did appear to help somewhat. But the blooms of algae continued. And in between the blooms, the scientist showed me that the extreme swings in dissolved oxygen meant that fish would not survive.
This kept me awake at night. Sometimes at dawn I’d be out there just watching. During one of these early morning visits I saw surface water boiling with resident yellow perch. After a late summer algae bloom that was in the process of decomposing, their oxygen was gone. They were suffocating. That was the last straw. This was my property, my water, and I was not managing it well. What was happening was inhumane.
I hit the books. I visited experts. Many of them came here. Lots of them several times. I hired more experts. And I learned the state of the art around water stewardship.
What I learned was profoundly disturbing. There was no fix. If I could not stop the nutrients, then the best existing option was aggressive aeration, just to keep the lake alive. And even then the lake zones between aerators would stratify and the deeper water, at least, would not have enough dissolved oxygen to support fish. Not even perch that can get by in low dissolved oxygen conditions. Certainly not trout that need three times the dissolved oxygen concentration perch get by on.
Fast forward ten years. Today Fish Fry Lake is the most productive wild fishery per acre foot of water in Montana. There’s no waterway in the state over 50 acre feet that even produces half the fish volume Fish Fry does. And water quality in FFL is far better today then when we started, even though the inflow water is just as nutrient polluted as when we started.
It was not a miracle. It was experimentation, prototyping, paying bills, more hard work, more prototyping…you get the drift! Ultimately, it was an incredible life lesson for me. We have a saying here in Montana: “Pioneers get shot with arrows!” Well, I dodged the arrows and now I offer you an actual road to follow. It won’t be as expensive or uncertain as my path either.
Here are the steps:
- Provide surface area and circulation throughout your waterway.
- Harvest more nutrients out of your waterway than are coming in.
If you do these two things in a nutrient polluted waterway it will become highly productive. And water quality will improve. Want more details? Read more here.