There’s no ominous background music with this story, no Quint onboard the Orca, and no Chief Brody or Matt Hooper to save the day.
Instead, it falls to people like Doug Keller, a DNR biologist who specializes in combating invasive species. He used to spend most of his time dealing with aquatic pests like zebra mussels, Eurasian milfoil and hydrilla.
That was until recently.
Although present in Indiana for more than a decade, Asian carp were largely an Illinois issue, particularly in Chicago, where the fish had advanced to within a few miles of Lake Michigan, stymied only by underwater electrical barriers and shipping canal locks.
“We’ve seen them in our rivers and side channels, slack water areas, for a number of years,” Keller said. “But it’s really been recently that we’re seeing fairly large concentrations, especially of the silver carp, because they are so much more visible. They are the jumpers.”
Bighead carp and silver carp — two of the fish species lumped under the catch-all label of Asian carp — were imported to the southern United States in the 1970s to clean catfish farm ponds of algae. They escaped into the wild in the 1980s and moved northward through the Mississippi River system.
As filter feeders, the carp gobble microscopic plankton and can consume 5 to 20 percent of their body weight daily. Adult bigheads can weigh 100 pounds; adult silvers, about 40 pounds. By straining out this important food source, they end up competing with many native fish species. In some areas of rivers in other states, Asian carp now make up 95 percent of the biomass.
Asian carp were first detected in Indiana in 1995 in the lower Wabash River. Biologists found them in small numbers during later surveys up the Wabash, most notably a 2008 research effort over a 105-mile stretch from Lafayette to the Roush Lake dam a few miles east of Huntington.
Then came Eagle Marsh.
The 705-acre restored wetland near Fort Wayne straddles two drainage systems — one flowing west into the Wabash and the other east into the Maumee River and eventually Lake Erie. The two watersheds normally don’t connect, but they have under certain flood conditions.
To bridge the divide between the watersheds, fish would have to leave the Wabash River and enter the Little River, clear two low-head dams in Huntington, enter Graham McCulloch Ditch, cross over a flooded Eagle Marsh to reach Junk Ditch, enter the St. Marys River and then the Maumee before taking off for Lake Erie.
Such a meandering journey may seem a remote threat, but it was a risk nobody wanted to ignore.
So, the DNR took the lead in 2010 by constructing a temporary barrier across a quarter-mile-wide area of Eagle Marsh. The 8-foot-tall mesh fence was completed under budget, at a cost of about $185,000.
As federal agencies led by the U.S. Army Corps of Engineers continue to evaluate a more permanent solution to the Eagle Marsh pathway, the DNR is working to educate anglers on the potential hazards of moving bait fish from one waterway to another.
One effort is to inform anglers who use cast nets to collect baitfish in areas below dams along the Wabash and its tributaries. Keller notes that the minnows of bighead and silver carp look strikingly similar to gizzard shad minnows, a common baitfish.
The message is that while it’s OK to collect and use baitfish, dumping unused live baitfish into other bodies of water is illegal and could have the added consequence of unknowingly spreading Asian Carp into new areas.
“There are still a lot of areas we can protect,” Keller said. “And the public can play a good, strong role in not allowing the spread of these things.”
It is illegal to possess the following fish and mussels alive without holding a species permit. If any of these are caught, they must be killed immediately and not returned to the water. Your cooperation is essential.
Regulations in red are new this year.
Purple text indicates an important note.