A new report commissioned by the Minnesota Department of Natural Resources recommends a barrier of sound, bubbles and lights to deter invasive Asian carp on the Mississippi River in Minneapolis.
The sound, light and bubble barrier at Lock and Dam No. 1 was recommended as the most viable option, even at a $12 project cost that could go as high as $19 million.
The sound, air bubble and light barrier would be considered experimental because nothing like it has never been tested in an environment similar to a lock chamber.
An electric barrier inserted into the water would be the most effective technology for Asian carp deterrence, but the report found significant public safety risks and corrosion concerns. The report also says it's highly unlikely the U.S. Army Corps of Engineers would approve an electric barrier at the lock.
The goal of a barrier at the lock and dam is to prevent the fish from using the lock chamber to gain access to the upper reaches of the river, which connects to other rivers and lakes. A lock barrier wouldn't block fish passage across the entire river, but rather deflect fish away from the smaller opening at the lock.
The Minnesota Legislature approved a $7.5 million for the design and construction of Asian carp barriers. $5.6 million of that money is allocated to design and construct the barrier at Lock and Dam No. 1. The DNR anticipates needing about $1 million for the design of the barrier, leaving $4.6 million for construction.
Asian carp have been found in the Mississippi River in Minnesota, but there is no evidence they are reproducing.
The fish are capable of eating 5 to 20 percent of their body weight each day, out-competing native fish for food.