Frequently Asked Questions

There are currently no established populations of Asian carps in the Great Lakes. There have been a few rare captures of individual species. Of the Bighead Carp, only three single specimens have been collected, all in western Lake Erie, between 2000 and 2003, and are believed to have been intentionally released. Of the Grass Carp, there have been approximately 34 captures since 2012 in the waters or tributaries of Lake Huron, Lake Ontario, and Lake Erie. Of those tested nine were found to be “diploid”, or fertile. It is likely that the fish caught were escapees from areas where populations were being used for aquatic plant control, or live releases. You can see more details about Grass Carp captures here. No Silver Carp or Black Carp have been found in the Great Lakes to date.

Recently, juvenile Grass Carp caught in the Sandusky River (in Ohio), a tributary of Lake Erie, were found to have been produced by natural reproduction. In addition, a genetic analysis conducted by the USGS recently confirmed that larval (newly hatched) fish collected from the Maumee River, another tributary of Lake Erie, during the summer of 2018 were Grass Carp. There is no evidence of an established population and monitoring continues. DFO is dedicated to the prevention of Grass Carp establishment in the Canadian Great Lakes basin and is prepared to respond to the increasing risk of Grass Carp in our waters. Moving forward, Asian Carp Program field operations will include greater surveillance of higher risk areas, including suitable spawning tributaries at the western-end of Lake Erie and southern portion of Lake Huron. 

“Carp” refers to one species of fish where “carps” refers to multiple species. The term Asian carps is used to refer to four species. The same goes for “fish” vs. “fishes”.

No.  Although Common Carp are invasive and native to Asia, they are not one of the four species we collectively call Asian carps.

Yes however, they are bony fishes and creating a market for these fish is not desirable.

In Canada, it is illegal to possess, sell, trade, transport or release any species of Asian carp unless dead and eviscerated. Any sighting should be reported to EDDMaps or the Invading Species Hotline at 1-800-563-7711. 

DFO does extensive early detection surveillance work. The MNRF conducts eDNA sampling. States surrounding the Great Lakes also conduct monitoring and surveillance work. Research by multiple groups is being done to learn more about these species and new techniques to prevent their establishment in the Great Lakes. The Chicago Area Waterway System (CAWS) is the largest known connection between the Mississippi River Basin and the Great Lakes. There is an electric barrier located near Romeoville, Illinois to prevent the movement of fish above and below the barrier. The barriers send an electric current through the water, discouraging fish from passing through. 

Learning to identify and report Asian carps is an important tool in prevention. Don’t trade, buy, or sell Asian carps. Don’t release unwanted pets or baitfish back into the water.

Bighead Carp eat zooplankton, Silver Carp eat phytoplankton, Grass Carp eat aquatic vegetation, and Black Carp consume mollusks. All 4 species can consume large amounts of food daily (20-40% of their body weight), outcompeting native species.

Yes. There is enough food, especially in Green Bay, Saginaw Bay, Lake St. Clair, and Lake Erie. Warm embayments in lakes Superior, Ontario, Huron and Michigan should also provide suitable amounts of food.

Asian carps have a narrow dorsal fin located relatively centre on their backs. They also lack barbels. Silver Carp and Bighead Carp have a low set eye, making them look almost upside down. Both Silver Carp and Bighead Carp are silvery in colour, with Bighead Carp having blotchy grey spots on their body. Grass Carp and Black Carp have their eye set in the middle of their head. Both Grass Carp and Black Carp have large scales with a cross-hatched pattern with Black Carp being black in colour, and Grass Carp being olive green in colour. Learn more about identification of native species vs. Asian carps here.  

No. Asian carps will not attack people, but Silver Carp do jump up to 3 metres out of the water in large numbers when startled by boat motors which is a hazard to human safety.    

Competition is important in natural selection. However, this is not natural competition. Asian carps aren’t a natural part of the North American ecosystems they invade. Invasive species have an advantage because they are extremely adaptable. Species like Asian carps that are able to reproduce in such large numbers, and grow to massive sizes very quickly, allow them to out-grow native predators, meaning there is no population control, and the competition for them is very easy.    

Asian carps are not established in the Great Lakes, or anywhere in Canada. The four species of Asian carps are established to varying extents within the United States. For more information about where individuals have been captured, please visit  https://nas.er.usgs.gov/viewer/omap.aspx

In their native range, Asian carps originated in major river systems in China and Russia. These river systems, including the Pearl, Yangtze, Min, Amur and Yellow, cover a geographic range from southern Russia to Northern Vietnam, and a climatic range from sub-tropical to temperate.

Assessment of the likelihood of establishment is based on the presence of a self-sustaining population, which is defined as occurring when individuals spawned within the Great Lakes basin, have subsequently successfully reproduced. For example, the establishment of Grass Carp in the Great Lakes is dependent upon availability of suitable spawning and nursery habitats, enough individuals for positive population growth, stock size required for effective recruitment, and survival of early life stages (considers predation, food availability and overwinter survival).

Asian carps were introduced to the Southern U.S. in the late 1960’s and 1970’s for use as biological control in aquaculture facilities based on their specific diets. Flooding events allowed at least three of the four species (Bighead, Silver, and Black carps) to escape these facilities and eventually make their way into the Mississippi River Basin. The spread of Grass Carp has largely been the result of stocking for the purposes of aquatic vegetation control.

No, there is no evidence of reproduction with native species.

No. Asian carps are very adaptable and would be able to survive the cold Canadian winters.

Scientists do not know exactly why this species jumps in this manner, which is unlike in their native range; it may be due to the overcrowded populations seen in the invaded areas.  When Silver Carp are in crowded population conditions and are frightened or startled by motion, they can jump up to 3 metres out of the water.  

In general, the physical connections represent higher likelihood than human-mediated releases; however, there is much lower certainty associated with the ranks of human-mediated releases. The highest likelihood of arrival into the Great Lakes basin is from the Chicago Area Waterway System into Lake Michigan. 

As few as 10 mature females and 10 (or fewer) mature males in the Great Lakes basin have a greater than 50% chance of successfully spawning if the fish locate suitable spawning rivers. 

Bigheaded carps have the potential to become a dominant part of the fish community biomass in favourable locations. This means that of all living biological organisms in the given ecosystem, Bighead Carp would be the dominant species. 

Lake Erie, including Lake St. Clair, and high productivity bays and other areas of Lakes Superior, Michigan, Huron, and Ontario. 

Suitable spawning tributaries are found in all lakes.
Canada: 41 suitable spawning tributaries in Canadian Great Lakes basin are accessible from the mouth to at least 100km upstream.
US: 22 suitable spawning tributaries in American Great Lakes basin are accessible from the mouth to at least 100km upstream.

This is identified as a critical knowledge gap within the risk assessment. 

Varies depending on arrival point within the basin but predicted to be less than 10 years for spread with direction likely Michigan to Huron to Erie. 

Less than 5 years after arrival into the connected Great Lakes basin via Lake Michigan.