The spread of Asian carp in Minnesota waters could threaten the $4 billion fishing and recreational boating industry. With carp now entering Minnesota from water systems in Iowa as well as the Mississippi River, the Department of Natural Resources says it's time to take stock of the risks.
In a report today, the DNR acknowledges the impossibility of knowing how Asian carp will affect Minnesota's fishing and boating traditions. But the agency notes that in other areas of the U.S. where they've become established, the carp sometimes make up as much as 90 percent of the biomass of the entire fish community.
The report analyzes the boating and fishing economy in four sections of the Mississippi watershed, including prime destinations like Lake Mille Lacs, the Brainerd and Whitefish chains, and Leech, Cass, and Winnibigoshish.
The report estimates that boaters and anglers spend more than $44 million annually on their trips. It points out that the tourism economy attracts people from all over the world, and that Minnesota's famous lakes in northwoods settings are an important part of that draw. It raises the question of whether the spread of the voracious Asian carp will tarnish that reputation and discourage visitors.
Steve Hirsch, director of the DNR's Division of Waters and Ecological Resources, said the agency wants to be able to compare relative costs, especially in difficult decisions such as whether to close the Mississippi River locks.
"The question is going to come up, if there's economic impacts on businesses associated with closing the lock," Hirsch said. "What are the economic impacts if we don't close it and the fish get upstream."
The Metropolitan Council has just released an analysis of the effects of closing the Upper St. Anthony Lock. That report says closing the lock would shift barge transport to trucks at a cost of about $24 million over the next 30 years.
Hirsch says the DNR is also applying for lottery money to study the risks of the spread of carp based on biology.
Future studies will try to predict where Asian carp are likely to go next, based on biology from their home territory and areas they've colonized, Hirsch said, noting that information sought on the carp includes the type of water conditions that they thrive under, and the similarity of those waters to Minnesota's rivers and lakes.
"They've been doing quite well in some of those systems, so we could take a look at what waters do we have. For example, what rivers do we have in Minnesota that are similar to, say, the Illinois River that might make them vulnerable," Hirsch said.
Hirsch says the DNR will be looking for answers to both the biological and the economic questions.