Ask The Board: Are Chemicals Safe for Fish?

Steve Reid, SRCLA Board Member since 2023, was recently asked if the chemicals used to control weeds have any negative impact on our fish or other beneficial biological entities (turtles, frogs, dragonflies) in our lakes.  Steve discussed this with one of the Association’s partners (in treatment), Dan McEwen,  Ph.D., CLP, Principal Scientist at Limnopro. Dan’s response is summarized below:

Generally speaking, the risks of any negative effects from chemicals on animals living in/around our treatment areas is less than the risk of leaving nuisance plants growing in the lake.  Dense plant growth leads to reduced oxygen, blue-green algae blooms, and can make foraging difficult for the types of sports fish most people want to catch (e.g., northern, bass, sunfish, walleye, etc.).  Chemicals that go into the lake are heavily regulated by EPA.  It would be misleading to say there was zero risk, but the risks are known and minimal, particularly given that animals can move, and the areas treated in lakes are small relative to the whole lake.

Dan also provided two documents, the first from the Aquatic Ecosystem Restoration Foundation, a non-profit organization interested in “science-based solutions to restore and maintain sustainable water resources” and the second is a government document written by John Madsen, who is now retired but arguably the world's expert on everything and anything that has to do with plant control in lakes.   You can read through his chapters 3 and 5 here.  

Great questions!  Thank you, Steve, for the follow-up on this important topic!