Last week I had the pleasure of sitting down with Dr. TJ Dunn from Rhinelander. Many know him as a veterinarian, but he is also a scientist with a great deal of knowledge about a compound known as Triclosan. This antibacterial pesticide has been given a great deal of press in recent years for its detrimental effects, both to us and to the environment. Our discussion centered around environmental factors - more specifically, fish in our inland lakes.
He and I have both been fishing since a very young age and he shared some of his thoughts and questions regarding chemicals such as triclosan and what may be happening to our inland lakes. I agreed the idea warranted further inspection, and he was happy to provide me with direction and information.
The gist of our conversation was: everything is connected. The chemicals we use in our daily lives will eventually find their way to our watersheds and lakes. What if, he asked, some of those chemicals were to blame for situations such as walleyes no longer naturally reproducing in waterbodies where they once flourished? Could there be a connection? I imagine there is a possibility.
While there is likely no "silver bullet" responsible for some of the crashes in walleye populations we have seen, we know the things we do on land have an effect on our waterways. We have seen it with various compounds from fertilizer to road salt. We discussed climate change as a possible cause - but if climate change is negatively affecting the walleye population, would it not be doing so on a more even scale, dropping populations in all lakes in an area? But there are still good walleye lakes and I imagine, they will remain good lakes if we prevent over-harvesting.
As we talked, I was reminded of an event which I covered last summer regarding a research project being conducted by a UW-Madison graduate student Martin Perales. He imagined the lakes in the Northwoods, at one time, as a mosaic. There were different lakes where different species of fish were prevalent each with its own "color," if you will. But, as people moved around, they also moved the fish around.
"Maybe we said, we want bass in this lake, and we want walleye in that lake, and we moved them around with us," he had said. Basically, his vision of the present-day lakes was no longer a mosaic of stained glass, but a picture where all of the lakes were the same "color," or had basically the same make-up of fish populations.
Dr. Dunn and I discussed this as well.
"Maybe we find out that now Lake Tomahawk is perfect for lake trout, for instance," he said. "But then we find another lake that is perfect for walleye. So, that is what we should have in those lakes. I think we need to let the lakes tell us what should be in them, not us deciding what should be in the lake."
We discussed how lakes change over time and how we, as humans, impact those lakes. This is where our discussion of triclosan came in. Was it possible this chemical has something to do with how lakes are changing?
Triclosan is in everything from antibacterial hand soap and toothpaste to many other products we all use on a daily basis. Once touted for its anti-bacterial properties, it has been found to have very negative side effects on fish and other animals in laboratory tests. In one test, the ability of fat head minnows to swim was deeply impaired by a seemingly insignificant amount of the chemical being present in the water. Things in the real world do not always mirror laboratory tests, of course, but it stands to reason this could become an issue in a lake, as well, if enough of the foreign substance is introduced.
This would lead one to wonder if part of the problem may not be in the lowest levels of the food chain, which Dunn and I spoke about as well. Unfortunately, he said, testing for compounds such as triclosan, while done in rivers below sanitation stations, is not done in freshwater lakes. Dunn spoke with me about the frustration he experienced when attempting to spur interest in completing that testing. He did, however, eventually find a company to agree to run the tests if he were to collect the samples. Those results, he said, should be available soon. I look forward to hearing about those results. More information regarding studies already completed looking at triclosan and its effects on the environment will be published here in the Outdoors section in the coming weeks.
Beckie Gaskill may be reached via email at firstname.lastname@example.org.