Fighting advancement of destructive invasive species has become a major part of modern natural resource management, and Indiana is no exception. Our Department of Natural Resources’ (DNR) latest major project involves trying to “fence in” the spread of Asian carp now threatening the future of the Great Lakes fishing industry.
Indiana is laying down a strategy of defense – and I do mean “da fence” – to stop the invaders from reaching the Great Lakes. The dimensions of a barrier constructed at Eagle Marsh near Fort Wayne are impressive.

Indiana’s carp barrier consists of a fence 1,200 feet long and 8 feet high, sporting dozens of 50-foot rolls of chain-link fence fastened to 123 four-inch posts by more than 1,000 wire ties, anchored in place by almost 120 concrete barriers weighing 2.5 tons each.

The barrier will keep the carp from reaching Lake Erie during times of high water and flooding. Construction of the 1,177-foot main fence and a supplemental 494-foot debris catch fence began in early September and was completed on Oct. 19.

Asian carp refers to several species of fish originating from Asia. Three species of the non-native fish, bighead, silver and black carp, were imported to the southern United States to keep aquaculture ponds clean and to provide fresh fish for markets.
Considered as captive and controlled in the confines of the catfish ponds, no one considered the threat for the Asian carp gaining access to the major river systems. Some of the fish escaped into the Mississippi River system in the 1980s and 1999s after flooding, and have expanded their range northward ever since.

Bighead and silver carp were first detected in Indiana in the late 1990s at Hovey Lake Fish and Wildlife Area in the southwestern corner of the state. Since then, they have moved up the Wabash, East Fork and West Fork of the White River, the Patoka River and the Ohio River and some of its tributaries in southern Indiana.

The final cost of the fence project is still being determined, but indications forecast it will be less than the $200,000 bid estimate. The U.S. Environmental Protection Agency and the U.S. Fish and Wildlife Service are funding the cost of the project through the Great Lakes Restoration Initiative.

“I tip my hat to DNR staff that tackled this project and got it done in a timely and efficient manner,” said DNR Director Rob Carter. “This may not guarantee Asian carp never get into the Great Lakes someday, somehow, but with a temporary barrier this substantial, it certainly seems unlikely this will be the route.”

The DNR took a lead role in the fence project after identifying Eagle Marsh as a potential pathway for Asian carp to move from the Wabash River system into the Maumee River, a tributary to Lake Erie. Although the Wabash and Maumee basins drain in opposite directions and have no direct connection under normal conditions, their waters do comingle under certain flood conditions in Eagle Marsh, a 705-acre restored wetland near Fort Wayne.

The DNR pursued the mesh fence barrier as a short-term option, while the U.S. Army Corps of Engineers and other federal agencies develop a permanent solution.

 “The completion of this fence marks another milestone met in the framework we laid out to prevent invasive Asian carp from establishing themselves in the Great Lakes. The barrier at Eagle Marsh is an example of what can be done through strong state and federal coordination,” said John Goss, former Indiana DNR director, now the Asian carp director at the White House Council on Environmental Quality.

Although placing such a large fence in the midst of a wetland restoration project creates aesthetic concerns, it was the right thing to do, according to Betsy Yankowiak, executive director of the Little River Wetlands Project managing Eagle Marsh.

“We spend so much on fighting invasive plant species and so much on volunteer time in that effort,” Yankowiak said. “We couldn’t handle it if Asian carp got through Eagle Marsh. We want to be proactive and be part of the solution, not part of the problem.”
While blocking passage of adult Asian carp is a primary goal of the fence, it also is designed to allow movement of water so as not to increase flood elevations and cause property damage. As an added component of floodwater monitoring, the U.S. Geological Survey installed gages on the fence for measuring water levels in effort to ensure the fence does not block water flow during significant flooding events.

DNR staff supervised the construction of the barrier fence by two Fort Wayne companies, Brooks Construction and R&C Fence.
Other defense plans for stopping the carp gaining access to the Great Lakes are showing success as well. Electric barriers in the Illinois River system leading to Lake Michigan seem to be accomplishing the goal of keeping the invaders out.

The University of Notre Dame is sampling sediment debris and analyzing the material for Asian carp DNA. The good news is no evidence of Asian carp was found in an environmental DNA sampling of Indiana ports and harbors near Lake Michigan by researchers from ND who did the study, they announced on Oct. 14.
The researchers collected 125 samples from five areas in northwestern Indiana. On Aug. 6, 14 samples were collected from the outflow of Lake George by kayak and by wading into the lower reaches of Deep River. All tested negative for bighead and silver carp DNA.

On Aug. 11, 25 samples were collected from Burns Harbor and 21 from Burns Ditch; all 46 samples tested negative. On Aug. 18, 11 samples were collected from the Gary Boat Slip and 54 samples from Indiana Harbor. All 65 samples tested negative.
 
The views and opinions expressed in this column are those of the author and not necessarily those of Farm World. Readers with questions or comments for Jack Spaulding may contact him by e-mail at jackspaulding@hughes.net or by writing to him in care of this publication.