Next summer, boaters are expected to be able to travel along the Fox River from Green Bay to Lake Winnebago.
That’s great for recreation, but it’s a concern for scientists.
Bart De Stasio, a Lawrence University biology professor, has been charged with studying invasive species in the river and detecting whether they have spread.
During a Newsmakers interview last week, De Stasio discussed a barrier near Wrightstown and how invasive species could hurt Fox Valley waterways.
Here are excerpts from the interview:
Tell us how you describe invasive species and why they’re so destructive.
Invasive species typically are any kind of species that isn’t evolved in one location. It’s something that comes in new, but, more than that, it’s something that causes a problem for society or for the ecology of the system. Or, if it caused a problem someplace else, it can be considered invasive in a new location.
What kinds of problems can they create?
In the Great Lakes, we have a problem with zebra mussels. That’s a species that evolved in Europe, in the Caspian Sea region. When it was transported here on boats, it became a problem because it attached to boats, to piers, to bouys. The problem that it causes for companies, especially, is it clogs intake pipes. Those have to be cleaned out periodically. That’s a brand new expense for companies.
Tell us about your study of the Fox River.
The Fox River study that’s going on now is to look at invasive species that might be coming in through the Fox River to the upland lakes, like Lake Winnebago and the upper pool lakes.
The Fox River is a location where they’re trying to open up the navigational waterway. The state has purchased all the locks and they’re refurbishing them. As part of that, they have to ensure that they don’t allow invasive species to go upriver.
They’ve decided to keep one of them closed as an invasive species barrier, the one that’s at Wrightstown at the Rapide Croche lock. Our job now it to monitor for invasive species before anything else happens to make sure they’re not allowing invasive species to go upriver.
What species are you finding?
Our study is set up so we can look at locations below the current invasive species barrier at Rapide Croche. What we’re finding is things you typically find in Green Bay or Lake Michigan that are known to be invasive are occurring just below that barrier.
We have round goby, a fish that again was brought in from the Caspian Sea region. The round goby is established near the De Pere dam, and we found it even above the Little Kaukauna dam. That’s a species that has the potential for ruining the ecology of systems. It feeds on the eggs of other fish, like yellow perch, and crustaceans that live on the bottom.
How do you actually conduct the Fox River study?
I hire two students every summer to help me. We have three sites identified below the Rapide Croche dam and three above it. At each of those locations, we got out at least four or five times each summer.
What we’re doing is sampling for all fish that would be in that location, all the invertebrates that live on the bottom and also looking at all the animals that live in the water, like water fleas. We identify everything that’s there, and determine whether it’s native or invasive.
Why is the round goby so bad?
The round goby has been shown in Lake Michigan and other Great Lakes to really affect the ecology, so how the food web functions. Because it is a predator on other fish eggs, it has the potential for affecting fish reproduction.
Yellow perch is one that’s a concern. In Green Bay, there historically has been a great yellow perch fishery — all the perch fish frys we have on Friday nights.
Are you concerned that the lock system will not stop the invasive species?
Yes. There’s a lot of concern about that because once you open up a lock and allow boats through it, what you’ve done is allowed a lot of water with those boats to be moved upstream.
Anything that’s attached to a boat or that are in the live wells, perhaps, or attached to fishing lines — there’s a spiny water flea that attaches to ropes and fishing lines — anything that gets moved with the boat can potentially be transported.
What are the safety measures built into the lock system?
The state authority that’s in charge of this system is called the Fox River Navigational System Authority. It was created in 2001 to oversee the opening of the locks. That authority put in place a management plan, part of which was monitoring invasive species to make sure they’re not moving them.
What they’ve done is provided educational opportunities for boaters to realize they shouldn’t be moving boats upstream unless the boats are clean.
They’re allowing boats to cross that invasive species barrier only if they’ve been properly cleaned. The plan is to construct a boat cleaning station that would lift boats over the lock at Rapide Croche and then use a hot-water treatment to clean those boats.
Why does the hot-water treatment system work?
We wanted to avoid using strong chemicals because then you have to deal with dangerous waste. We investigated the idea of using hot water, which is easy to remove.
The Fox River Navigational System Authority contracted with us to do studies to test how hot would the water have to be and how long the boat would have to be in contact with that water.
I had a student work on that project with me and we determined that 110 degrees would be enough to kill the species we were seeing, and that they would have to have a five-minute immersion. The plan is to have a hot-water dunk tank essentially. The gear would have to be treated as well.
What concerns have you heard from boaters?
One of the main ones is that this transport of boats above the species barrier will allow sea lamprey or round goby to get through. Fish are usually a little easier to deal with because they don’t attach to the bottom of the boat. So if any boat is observed to have live fish on it, it will be denied passage.
How else can species get through?
One of the issues is that there are a lot of boat landings below Rapide Croche, so smaller boats that can be taken out of the water are transported around the barrier and put back in the water. In fact, we’re pretty sure that’s how the zebra mussel was introduced into Lake Winnebago back in 1998, that there was a boat in Green Bay for the first half of the summer and it was moved to Winnebago the second half and introduced that species.
Our barrier is not going to stop everything from coming in, but the authority is charged with making sure it doesn’t get through that (specific) barrier.
Is it a matter of educating boaters?
That’s a big part of it. The Clean Boats, Clean Waters program is an effort to make boaters realize they should not be transporting boats from one body of water to the next in a short time. The recommendation is to have at least a five-day drying period, if not longer, and to make sure a boat is fully cleaned before it’s moved to a new body of water.
Lake News: Q.