Asian carp: A great threat to the Great Lakes.

Image by Asian Carp Regional Coordinating Committee |

Image by Asian Carp Regional Coordinating Committee |

Unless you live near one of the Great Lakes, you may not have heard much about the invasive Asian carp threatening to invade Canadian waters from the south. Aside from causing physical and economic problems, Asian carp are a huge threat to native species and ecosystem biodiversity.

Asian carp originated in rivers in China, Russia and northern Vietnam. They occupy a climate similar to that of North America, which means the carp have a good chance of thriving in the United States and Canada. Great Lakes waters are not too cold for Asian carp, and contain a plentiful supply of food. In fact, Canada’s Department of Fisheries and Oceans (DFO) has conducted a risk assessment for Asian Carps in Canada, and found that they have a high, certain chance of surviving, reproducing and colonizing our waters.

Aquaculture managers first brought Asian carp to the southern United States in the 1970s for biological control of algae, plant and snail growth in aquatic farms. Eventually the Asian carp managed to escape their aquaculture ponds because of flooding. The escapees were able to breed successfully in the wild and create a large population of invasive Asian carp in the Mississippi river. From there they spread north and up tributary rivers. It is no surprise the carp are so good at spreading, since they can jump three meters out of the water (sometimes even doing popular dance routines). They are now present in many parts of the United States, right up to the states that border on the Great Lakes.

There are four different species of Asian carp: Silver carp, Bighead carp, Grass carp and Black carp. Unlike these Asian carp, the Common carp is a fish that also came from Asia to North America, but it has been here much longer and is not posing the same threat as the invasive carp species that we call Asian carp.

Asian carp are a huge threat to biodiversity. They have replaced native species in some parts of the Mississippi and nearby lakes. They grow extremely fast and can weigh up to 40 kilograms! Asian carp can eat 20 per cent of their body weight in plankton every day, which means very little plankton survive to become adult aquatic species and reproduce. Less plankton also means less food for native fishes. Their voracious hunt for food tends to leave lakes a river bottoms mucky and less vegetated, which makes it harder for other fish to find food, find cover from predators and spawn. In some parts of the United States, Asian carp are so dominant that they now make up 80 per cent of the habitat’s biomass, causing enormous loss of biodiversity. Asian carp also have parasites, like the Asian tapeworm. We still don’t know how these parasites might affect native fish species. 

If Asian carp make it to the Great Lakes they are expected to eat our native fish and their food supply, and damage Ontario’s fishing, boating, wildlife viewing and lakefront activities, which are an important part of Ontario’s economy and recreation.

These carp are also a physical danger to people. They are very large, strong and heavy, so when they jump out of the water they can easily injure boaters, swimmers and water skiers by colliding with them. Asian carp can also harm fishing gear that is not designed for such dense amounts of large fish.

Asian carp could get into the great Lakes in two ways. The more obvious route would be via the Chicago Area Waterway System, which is a system of canals connecting Canadian and American waters. There are also low lying parts of Illinois that connect Canadian and American waters during flooding.

Humans also have the potential to bring Asian carp into Canadian waters. Emptying bait buckets from one waterbody to another could accidentally release young Asian carp in the Great Lakes. Ballast water from boats could also release Asian carp into our waters. Trade of live fish for pets or food could also result in the introduction of Asian carp to Canada.

The United States are making an effort to prevent Asian carp from entering Canadian waters. Additionally, Ontario and all states bordering on the Great Lakes have made it illegal to transport, possess or sell Asian carps. DFO and researchers are also monitoring and testing Great Lake waters. Ontario is creating an Asian Carp Response Plan in case the species begins to invade Canadian waters.

So what can we do? If you go fishing, make sure you don’t dump unwanted bait in the water! Make sure it goes into the garbage on land. If you are fishing, make sure you are able to check your bait and identify whether it might be a young Asian carp. It is easy to confuse young Asian carp with native Ontario fish species. Whether you fish or not, do not release any live fish into into Ontario lakes or rivers and do not import live fish into Ontario. Anyone who has identified Asian carp in the wild is asked to report it to 1-800-563-7711, the toll free Invading Species Hotline. If you have information regarding the illegal importing, distribution or sale of Asian carp, you can report it to 1-877-847-7667 (toll free).