Great Lakes

Lake Erie: Asian Carp Remain A Serious Threat

Lake Erie is at risk of an Asian carp invasion, which could make a devastating impact on the ecosystem. Although the threat to the Great Lakes is nothing new, researchers have determined Lake Erie may suffer the worst consequences.

The term “Asian carp” actually refers to five different species, including bighead, blackhead, grass, silver, and large-scale silver carp. As discussed by the Michigan Department of Natural Resources, all five originated in Asia and are considered invasive species in the United States.

Although all five species of Asian carp pose a threat to U.S. waterways, bighead and silver carp pose a specific threat to the Great Lakes.

As they are filter feeders, bighead and silver carp were originally brought to the United States in the 1970s as a natural means of filtering water in catfish farms and wastewater treatment facilities.

It is unclear how the Asian carp made their way from the catfish farms and wastewater treatment facilities into local waterways. However, many researchers believe the fish were simply washed out of the ponds during periods of heavy flooding in the 1990s.

Over the next 20 years, the invasive species spread throughout the Great Lakes and Mississippi River regions. Although they originated in Asia, the carp thrived in the U.S. waterways and multiplied at an alarming rate.

Asian carp are a specific threat to the Great Lakes, as they are expected to compete with native filter feeders. They also threaten young yellow perch and walleye, which are a vital part of the Great Lakes ecosystem. The disruption to the food chain could negatively impact commercial and recreational fishing throughout all five Great Lakes.

Silver carp also pose a physical threat to humans, as they leap out of the water when they are disturbed. As they often travel in large schools and can weigh up to 40 pounds, the invasive species have damaged small boats and injured humans.

A recent study, conducted by the Transactions of the American Fisheries Society and published by Taylor Francis Online, suggests Lake Erie may suffer the worst consequences of an Asian carp invasion.

According to the study, the invasive species may benefit and increase the number of smallmouth bass in Lake Erie. However, Asian Carp will most likely decrease the population of emerald shiners, gizzard shad, rainbow trout, and walleye.

As they are expected to thrive, bighead and silver carp could “become up to 34 percent of Lake Erie’s biomass.” However, the researchers concluded the “lakewide impacts… will not be as great as some have feared” if the carp do not feed on the sport fish larvae.

Milwaukee Wisconsin Journal Sentinel reports Asian carp can survive on a diet of plankton — which is plentiful in Lake Erie. Therefore, it is unclear whether they will feed on the larvae.

The Transactions of the American Fisheries Society study did not explore the possible impact on the other four Great Lakes. However, prior research suggests Lake Michigan and Lake Superior are not as vulnerable as Lake Erie.

Lake Erie is the most shallow, and smallest of the Great Lakes by volume. It also has more plankton than the larger and deeper lakes.

With less plankton, Lake Michigan and Lake Superior are less likely to support larger volumes of Asian carp. Lake Erie, however, provides the perfect environment for the invasive fish.

At this time, Asian carp have not established themselves in Lake Erie or any of the other Great Lakes. In an effort to lessen the possibility in the future, electrical barrier systems were installed on the Chicago Sanitary and Ship Canal. Unfortunately, “silver carp and bighead carp eDNA was detected in Lake Erie” in 2011.

[Image via Shutterstock/KPG_Payless]

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