Why Asian carp pose a threat to the Great Lakes

There are many challenges facing the Great Lakes, among them the threat of a non-native species — Asian carp — entering its ecosystem.

According to an October report released by the Great Lakes Sea Grant Network, there is “much uncertainty about the potential Asian carp population abundance in the upper Great Lakes (Superior, Michigan, Huron), though Lake Erie may be a very suitable habitat for Asian carp.”

What are Asian carp?

There are four kinds of Asian carp that threaten the Great Lakes: silver carp, bighead carp, grass carp and black carp.

Grass carp were the first to be brought to the United States from Southeast Asia for use in

aquaculture in the 1960s the other three followed in the 1970s. The fish were also used at wastewater treatment facilities keep retention ponds clean. According to AsianCarp.us, flooding allowed these fish to escape into the Mississippi River system and migrate into the Missouri and Illinois rivers. The three rivers are all connected and allow fish to swim freely between them. Additionally, the Illinois River is connected to the Great Lakes by a manmade connection known as the Chicago Sanitary and Ship Canal.

Silver and bighead carp are considered the threat to the Great Lakes, according to the Great Lakes Sea Grant Network. Both are moving up the Illinois River toward Chicago Area Waterways System. Grass carp have been found in the Great Lakes watershed. The Sea Grant Network study stated that there is evidence of successful grass carp spawning in the Sandusky River, a Lake Erie Tributary.

Black carp are found in the Mississippi River, currently near the Iowa-Missouri border, but they are moving north toward new habitats. Why are they a problem? Bighead and silver carp feed on plankton by filtering it out of the water, while grass carp eat vegetation and black carp eat mollusks like clams and snails. Bighead and Silver carp are capable of eating 5-20 percent of its bodyweight each day.

“Asian carp are voracious and often outcompete native fish for food and habitat, which is of great concern to wildlife and resource managers,” the Sea Grant study stated.

In the Great Lakes, Asian Carp will compete with native fish like ciscos, bloaters and yellow perch, which in turn are fed upon by predator species including lake trout and walleye. How healthy is Lake Erie? We take a look at the health and popularity of Lake Erie as the summer recreation season begins. In addition to the growing algae problem, this three-part series will look at invaders such as Asian carp and also the state of recreational boating.

According to AsianCarp. us, there are no North American fish large enough to eat an adult Asian Carp.

“White pelicans and eagles, however, have been seen feeding on juvenile or smaller adult Asian carp,” the site stated. “Largemouth bass have often been observed feeding on small juvenile Asian carp, and many other native predators probably also feed on them before they grow too large. However, Asian carp produce many offspring which grow quickly and, if conditions are good, rapidly become too large to be eaten by North American predators. Juvenile Asian carp are also known to move into very shallow water where they are inaccessible to many large predators.”

An established Asian carp population could also threaten Great Lakes recreation. Silver carp are known for leaping out of the water at the sound of a boat or jetski motors, causing physical harm to people and property, according to AsianCarp.us.

Recreational boating is a $16 billion a year industry in the Great Lakes. Recreational and commercial fishing accounts for another $7 billion.

“In Ohio alone, Lake Erie is a vital economic engine — creating 100,000 tourism-related jobs in Northern Ohio,” state Rep. John Rogers, DMentor-on-the-Lake, said in March. “As one of our nation’s greatest freshwater water resources, the lake not only provides drinking water for 3 million Ohioans, it is also responsible for generating $750 million in state and local taxes, attracting 1.5 million hunters and anglers who alone spend $2 billion in Ohio. If we fail as a nation to address this growing threat, the damage caused by this invasive species will be irreversible.”

Three bighead carp were collected in Lake Erie between 1995 and 2000 in Western Lake Erie, according to AsianCarp.us. Since 2004, the U.S. Fish and Wildlife Service have monitored western Lake Erie in Sandusky and Toledo using trammel nets as a response to those discoveries. The surveillance has not netted any more bighead or silver carp.

“These sampling suggest a reproducing population does not exists in Lake Erie,” AsianCarp.us stated.

Last June an 8-pound silver carp made its way up the Illinois River, past the Brandon Road Lock and Dam near Jolliet, Illinois, and was found beyond the electric barrier and nine miles from Lake Michigan.

According to a news release that followed an autopsy of the fish spent a quarter of its life in the Des Plaines River watershed before being caught and removed from the Little Calumet River above the U.S. Army Corps of Engineers’ electric dispersal barriers.

“Though it is not known how the fish was able to arrive above the barrier defense system, analysis shows that the fish spent no more than a few weeks to a few months in the stretch of river where it was found,” the release stated.

Prevention efforts

Two months after the silver carp was found, a federal report was released analyzing options for upgrading the Brandon Road Lock and Dam. The report was originally supposed to be released in February 2017, but was delayed by the Trump administration.

The report proposes $275 million for technological and structural upgrades at the site.

Among technologies the report endorses is using sound systems to create “complex noise” underwater that would deter fish from the Brandon Road area, plus installing a new approach channel and placing an electric barrier at its downstream end that would repel fish and stun them if they get too close. Brandon Road is several miles downstream from an existing barrier network.

Other measures would include installing water jets to wash away “small and stunned fish” that might be caught up around barges, plus a new lock where floating invasive species could be flushed away.

The report says the federal government would pay 65 percent of the costs project’s costs, with the rest coming from a “non-federal sponsor.”

The Brandon Road study has received some pushback from elected officials and business leaders in Illinois and Indiana, who have argued that significant changes to the Brandon Road complex could hamper cargo shipment on the busy waterway.

Members of the U.S. Senate and House of Representatives have been pushing for the U.S. Army Corps of Engineers Chief’s Report Milestone for the Tentatively Selected Plan for the Brandon Road Study to be released no later than February 2019.

That effort was re-upped this month when Sen. Rob Portman, R-Ohio, included the February 2019 completion date as a requirement in the proposed “America’s Water Infrastructure Act.”

State lawmakers have also urged support of the study. Rogers and fellow state Rep. Kent Smith, D-Euclid, introduced legislation in March urging U.S. Congress to support federal funding for the U.S. Army Corps of Engineers in its efforts to stop Asian carp from invading the Great Lakes.

“We will either stop Asian carp at the Brandon Road Lock, or we will wish we did,” Smith said. “Our Great Lakes and billions of dollars in economic activity hang in the balance. The longer we wait, the greater the threat of an ecosystem catastrophe.”