Wednesday, July 22, 2015
I called the local Soil and Water office, where the woman said the fish kill was probably due to chemical run-off from a nearby field, and she suggested I call a fish biologist at the Department of Natural Resources, which I did. But he wasn't in his office, so I left a message, and of course he called back when I wasn't home. He spoke to my son and told him to call the EPA, which my son did. The person on the phone there said that someone would probably come out to investigate.
Today I realized that if the EPA put our address in a GPS system, they'd arrive at the pond down the road and leave because it looks lovely. (GPS doesn't know where we are.) So, I called the EPA this morning and had a lengthy conversation with someone who told me that they don't usually get involved in private pond problems unless there is evidence of definite pollution. So, he suggested I call the DNR. I told him that DNR had actually referred us to him, and he said that maybe DNR thought the EPA would be interested, but they're not, and the fish biologist at DNR would be our best bet in figuring out what happened. He said that most fish kills are due to oxygen deprivation, but he also gave me the name of a water testing lab in Peoria in case we wanted to check for the presence of chemicals in the water.
I emailed the water testing lab, and they said the fish kill was probably due to oxygen deprivation, but for a few hundred dollars they could test the water. So, I've spent the last few hours reading about fish kill and duckweed.
As you can see in the above photo, the surface of the pond is mostly green. It's not algae though. It's duckweed, which has never been a problem until this year. Apparently it can be spread by wild waterfowl visiting your pond and dropping off a plant or two, which can then multiply every single day! And before you know it, the surface of your pond is covered with duckweed. The good news is that it killed the algae because it doesn't allow any light to get into the pond. The bad news is that it's as bad for the fish as a huge algae bloom because it can ultimately reduce their oxygen and suffocate them.
So, we have one vote for poisoning and two votes for suffocation, and my reading is leading me to think that suffocation is probably the culprit. I did call the fish biologist again, however, and am waiting for him to call me back.