Some places in the Great Lakes might be better for Asian carp than others…
This is the Environment Report. I’m Rebecca Williams.
Let’s take a second and play a game.
When I say “Asian carp” what’s the very first thing you think of?
Maybe… it’s this:
“They’re jumpin’ pretty good, look at that! Ohhh that one may have hurt… Ohhh!”
Those are silver carp. They’re the jumpers. And if there are a lot of them packed in shoulder to shoulder in a river channel… it can be dangerous.
Duane Chapman is a leading carp expert. He’s with the U.S. Geological Survey in Missouri.
“They’ve hurt a lot of people – I’ve been hurt by them – I’ve seen a couple of broken jaws, people have been knocked off boats.”
Asian carp were imported to the U.S. in the 1970’s and used in research ponds and fish farms. At some point, they escaped, and they’ve been making their way up the Mississippi River system ever since.
The question that’s on a lot of people’s minds now, is what will happen if Asian carp get established in the Great Lakes.
John Dettmers is a senior fishery biologist with the Great Lakes Fishery Commission. He’s also one of the authors of a new peer-reviewed risk assessment.
“The risk of Asian carp establishing themselves and having measureable consequences to Great Lakes fish and aquatic communities is pretty high especially in Lakes Michigan, Huron and Erie. A little bit less of a risk in Lake Ontario and a bit less risk than that in Lake Superior.”
Scientists are the most concerned about bighead and silver carp. Both species eat plankton. Those are tiny plants and animals at the base of the food chain that a lot of other things like to eat.
Duane Chapman with the USGS also worked on the risk assessment. He says between 1995 and 2000, three bighead carp were caught in Lake Erie.
“Those fish were extremely robust. They were very fat.”
Biologists think those three carp were put in the lake intentionally… and Chapman says there’s no evidence yet that there’s a reproducing population in Lake Erie.
But he says Lake Erie would be very well suited for carp, and especially the western part of the lake because there’s a lot of plankton there.
“That would be better habitat than just about any place in the Great Lakes for Asian carp growth. It also tends to be habitat for important fishes like walleye and yellow perch. That’s a little bit scary.”
He says there could also be some negative impacts on salmon at certain stages of their lives.
Other fish experts have questioned how well carp would do in the Great Lakes.
Gerald Smith is a professor emeritus in the Museum of Zoology at the University of Michigan. He was not involved in the new risk assessment. He says he agrees with the report overall… but:
“I think they left out the importance of predators. All carp start out as eggs, juveniles or larvae. They have to grow up through a food chain that includes more large predators than Asian carp face anywhere else in the world.”
He says it’s uncertain how well little carp would do against those predators.
Duane Chapman says baby Asian carp might be able to escape a lot of those predators. He says there are many shallow wetlands in the Great Lakes region where baby carp could hide.
All of the scientists made a point of saying that we should keep Asian carp out of the Great Lakes. And Duane Chapman says… even if a few carp do turn up down the line… it’s not time to give up.
“I want to make it real clear that there’s a sense you get a couple of fish, a male and a female, and it’s game over. That’s absolutely not the case.”
He says typically in a big system like the Great Lakes, it takes a large number of fish to establish a reproducing population. So he says it makes sense to try to keep the numbers of carp in the Lakes low.
Special thanks to Long Haul Productions for their jumping carp audio.
That’s the Environment Report. I’m Rebecca Williams.
Our series wraps up tomorrow with a look at people who are trying to make some money by selling carp.