Asian carp in North America facts for kids
Asian carp are a group of fish that cause big problems when they get into new places. They are a major threat to the environment, economy, and way of life in the Upper Midwest and Great Lakes region of the United States and Canada.
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What are Asian Carp?
Asian carp are fish species that cause harm when they are introduced to new environments. Their numbers have grown a lot, worrying scientists. These carp compete with local fish for food and living space.
The four most well-known types of Asian carp that cause problems are bighead, silver, black, and grass carp. Each one causes different issues:
- Black carp eat native mussels and snails. Some of these snails and mussels are already in danger.
- Grass carp can change the food web of a new area. They do this by changing the types of plants, small creatures, and fish living there.
- Silver carp eat plankton. Plankton is tiny food needed by baby fish and native mussels.
Jumping Silver Carp
Silver carp are famous for jumping high out of the water. They get scared easily by boats and jet skis. These fish can leap up to 2.5–3 meters (8–10 feet) into the air! Many boaters have been hurt by hitting these jumping fish.
Silver carp can grow very large, up to 45 kilograms (100 pounds). People even have a special event called the Redneck Fishing Tournament in Bath, Illinois. They try to catch the jumping carp in nets.
Asian Carp as Food
Asian carp have been a popular food in Asia for thousands of years. There are special recipes like sweet-and-sour carp (Tángcù Lǐyú) and thick miso soup with carp (Koikoku). However, many people in North America think Asian carp are like common carp. Common carp are bottom-feeding fish with many bones, and they are not usually eaten here.
The meat of Asian carp is white. It is said to taste like cod or a mix of scallops and crabmeat. They are low in mercury because they do not eat other fish. To make them more popular, they have been given new names like silverfin or Kentucky tuna. Some people even make and sell dishes with carp. They also use the fish parts to make fertilizer.
Some people thought about collecting carp eggs for caviar. One bighead carp was found with over 2 million eggs! But there is no market for carp eggs in America yet. There is a group trying to make carp eggs popular in Europe.
In 2015, a company in Chicago started making pet food with Asian carp. This helps reduce the number of carp in Midwest waterways.
How Common Carp Came to the U.S.
The common carp came to the U.S. in 1831. It has been widespread for a long time. In the late 1800s, the U.S. Fish Commission spread them widely as a food fish. These carp often pull up plants and make the water muddy. They do this by digging in the mud for food. This can harm native species. But in Europe, common carp are popular for sport fishing. This type of fishing is also becoming more popular in the United States.
How Asian Carp Came to the U.S.
In the 1970s, fish farmers in southern U.S. states started bringing Asian carp from China. They used the carp to help clean their ponds. The number of bighead and silver carp has grown a lot in the Mississippi River basin.
Many people think the big floods of the 1990s helped Asian carp escape into the Mississippi River. But this is not entirely true. Bighead and silver carp were already in the Mississippi River basin before 1990. Grass carp have been reproducing in the Mississippi River since the 1970s.
The term "Asian carp" usually means grass, black, silver, and bighead carp. This is because they are the most common ones and were brought to the U.S. later. Of the Asian carp brought to the U.S., only two are not firmly established. These are the crucian and black carp. Crucian carp may even be gone from the area. However, since 2003, several adult black carp have been caught in rivers connected to the Mississippi River. This means black carp are probably established in the U.S. In South Florida, sterilized grass carp are put into canals. They help control a plant called hydrilla, which can block water flow.
Where Asian Carp Are Spreading
Bighead, silver, and grass carp are well-established in the Mississippi River basin. This includes the Ohio and Missouri rivers. Their numbers can get very high, especially bighead and silver carp. These carp have been caught from Louisiana to South Dakota, Minnesota, and Ohio. Grass carp are also established in at least one other river system in Texas.
Threat to the Great Lakes
The EPA is worried that Asian carp might move into the Great Lakes. In 2002, the U.S. Army Corps of Engineers (USACE) built an electric fish barrier. It is in the Chicago Sanitary and Ship Canal. This canal connects the Mississippi River basin to the Great Lakes. It is the only water link between these two large areas. The first barrier was a test. After it worked well, a permanent barrier was started in 2004. The USACE has also found 18 other places where carp could move from the Mississippi basin into the Great Lakes.
Asian carp have been found in Lake Calumet in Illinois. Grass carp have been caught in every Great Lake except Lake Superior. But there is no sign of them reproducing there yet. No silver carp or black carp have been found in any Great Lake. Common carp are already very common in the Great Lakes.
A report in 2012 said that physically separating the Great Lakes and Mississippi River is the best way to stop Asian carp. This would also stop other invasive species from moving between the waters.
Stopping these carp from spreading into Lake Erie is a big concern. Lake Erie is a perfect home for the carp. They could take over and push out the native fish. This would hurt the sport-fishing industry there. It is hard to catch these carp with normal fishing methods. In October 2013, scientists found that Asian carp had reproduced in Ohio's Sandusky River. This river flows into Lake Erie. A 2015 study showed how much damage a carp invasion could cause in Lake Erie.
In May 2013, a test found silver carp eDNA in Sturgeon Bay in Lake Michigan. eDNA is tiny bits of DNA left by living things. This means silver carp were active there. Scientists planned to re-test in May 2014.
In 2016, many Great Lakes boat captains asked for quick action against the carp. In August 2016, the Michigan Department of Natural Resources said they found no Asian carp in their samples of Michigan waters or the Great Lakes.
Threat to the Upper Mississippi River
The United States Geological Survey and the University of Minnesota studied how to find fish using eDNA. This was after eDNA of Asian carp was found in Minnesota waterways in 2011. They studied the Mississippi and St. Croix Rivers. However, new research did not find the carp again. This could be due to different testing methods or the carp leaving the area. Still, several carp have been caught in Minnesota in recent years.
In 2011, the National Park Service made a plan to stop Asian carp in Minnesota.
The Upper Mississippi CARP Act was proposed to Congress in 2013. This act would allow the Secretary of the Army to stop the spread of Asian carp and remove them. It would also require the Army Corps of Engineers to close a lock if carp are found near the Twin Cities. U.S. Senator Amy Klobuchar said that Asian carp threaten Minnesota's environment, recreation, and fishing industries.
In 2015, the locks at St. Anthony Falls Lock and Dam were closed to control the carp. This made Minneapolis the end point for boats on the Mississippi again.
In June 2015, bighead carp were caught by recreational fishermen in the St. Croix River. In February 2016, bighead carp were caught by commercial fishermen in the Minnesota River. The Minnesota Department of Natural Resources was concerned about these catches.
Asian Carp in Canada and Mexico
In Canada, the federal Department of Fisheries and Oceans has looked at the risk of Asian carp invading Canadian waters. This is especially true for the Great Lakes. A few bighead and grass carp have been caught in Canada's parts of the Great Lakes. As of 2019, Asian carp are known to be established in Canada.
There are worries that silver carp might spread into the Cypress Hills in Alberta and Saskatchewan. They could move through rivers that flow south into the Milk River. The Milk River flows into the Missouri River, where Asian carp are already common.
In July 2015, two grass carp were found in ponds near Toronto's Lake Ontario waterfront. Both fish were male and could reproduce. This does not mean they are reproducing widely in Lake Ontario yet. U.S. and Canadian groups are working together to find out where the fish came from and how to stop them. In early September, three more grass carp were found near the Toronto Islands.
In Mexico, grass carp have been established for many years in at least two river systems. They are considered an invasive species there. No other Asian carp are known to have been introduced to Mexico.
Stopping the Invasion
Other ways to reduce Asian carp numbers include encouraging people to eat more carp. Fisheries are also shipping the fish to other markets, like Israel.
As of 2016, there are efforts to bring back Alligator gar between Tennessee and Illinois. Alligator gar cannot eat adult carp, but they can eat young carp. This helps control the carp population.
Laws to Fight Asian Carp
In July 2007, the U.S. Department of the Interior said that all silver carp and largescale silver carp are harmful species. This was under the Lacey Act. In July 2012, Congress passed a transportation bill that included the "Stop Invasive Species Act." This act tells the USACE to speed up plans to protect the Great Lakes from Asian carp.
U.S. Representative Dave Camp and Senator Debbie Stabenow introduced the Close All Routes and Prevent Asian Carp Today (CARPACT). This act tells the Army Corps of Engineers to stop Asian carp from entering the Great Lakes. This was estimated to cost over $30 million in 2010. The act will make sure certain locks and gates are closed until a better plan is made. It will also improve existing barriers and monitoring systems. The Army Corps of Engineers can also use fish poisons, commercial fishing, and netting to remove the carp. A 2012 report said that physically separating the Great Lakes and Mississippi River is the best long-term solution.
In November 2009, carp genetic material was found beyond two electric barriers. This meant only one lock/dam was left between the carp and Lake Michigan. Joel Brammeier of the Alliance for the Great Lakes called it an "emergency." He mentioned the threat to the environment and boaters. He and others wanted the lock closed immediately. But some doubted if shipping traffic could be stopped. A spokeswoman for USACE said "All options are on the table."
In December 2009, the USACE closed one electric barrier for repairs. The Illinois Department of Natural Resources then put 2,200 gallons of a toxin called rotenone into the canal. Rotenone kills fish but is not harmful to humans or most other water life. Many fish died, but only one carp was found. It was found almost six miles below the electric barriers. This fish kill cost $3 million and produced 90 tons of dead fish.
On September 8, 2010, John Goss was named the Asian Carp Director. His job is to advise on Asian carp issues. He also helps coordinate efforts between federal, state, and local groups to control the carp.
The Stop Asian Carp Act of 2011 was introduced. It asked the Secretary of the Army to study how to separate the Great Lakes and Mississippi River basins. This would involve things like electric barriers. The act gave 30 days to start a study on the best ways to separate the Great Lakes. The study had to look at how to stop carp from spreading through floods, wastewater, and boat traffic.
In 2012, new bills were introduced in the U.S. Senate and House. These bills aimed to speed up parts of the Stop Asian Carp Act of 2011. The new laws tell the U.S. Army Corps of Engineers to finish their study within 18 months. This study is about how to separate the Great Lakes from the Mississippi watersheds.
