Thu. Feb 29th, 2024
Invasive species fighters: let's keep our lakes in good condition

Today’s post comes from our friends at the Invasive Species Center.

Our Great Lakes are Big with a capital “G” and we want to keep them that way.

Ontario’s parks offer pristine outdoor experiences with nearly two dozen provincial parks located on the Great Lakes.

Did you know that invasive carp are not established in the Great Lakes, but they threaten nearly every aspect of our precious lakes? Learn more about these fish and what you can do to keep them away.

What are invasive carp? know your enemy

carp species

Invasive carp are four species of carp (bighead, black, grass, and silver) that are members of the cyprinid family and are related to several varieties of minnows.

All of these carp are native to the rivers, reservoirs and lakes of China and southern Russia.

All four species have escaped into the wild in North America. Three of these species have established self-sustaining populations, particularly in the Mississippi waterway system, although it is likely that black carp have also become established.

Invasive carp prefer cold to moderate water temperatures, such as those found in the Great Lakes, and can reproduce rapidly. They can eat up to 40% of their body weight. every day, and they can grow more than 25 cm in their first year. These fish can reach 40 kg in weight and more than a meter in length when mature.

Bighead and silver carp feed on plankton, the base of the aquatic food web, and spread aggressively.

Vibrations in the water excite silver carp, causing them to jump up to 3 meters (9 feet) out of the water. Vibrations caused by boat propellers have made silver carp a hazard to boaters and water skiers, and have caused serious injuries to recreational users.

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Recreational impact

Woman fishing in a calm lake

Imagine you are sitting at your favorite campsite and the whole family is ready to go swimming. You dip your toes in the water, only to discover that the water is cloudy and unsuitable for swimming during a perfect beach day.

Are you a navigation lover? An invasion of invasive carp could mean flying silver carp jumping around you while you boat on your favorite lake! This could make your trip riskier than relaxing.

Do you feel like fishing for lake trout? Invasive carp will outcompete them and there will be little chance of you being able to catch this native species.

Economic impact

Boat on a misty morning

The negative effects of a possible invasion of invasive carp go beyond recreational activities. An invasion of invasive carp would affect our economy and our environment.

The full effects and consequences of aquatic species invasions may take decades to emerge. The Binational Big-headed Carp Ecological Risk Assessment (DFO, 2012)1 determined that after the arrival of the invasive carp, the impacts would take 7 years to materialize.

Fisheries and Oceans Canada used this information to conduct a Socio-Economic Impact Assessment (DFO, 2014)2 to better understand the impacts of invasive carp establishment in the Great Lakes. The study uses 2011 as the base year and an adjusted base of 2018 to consider 20- and 50-year impacts.

For the purposes of estimating the impact in Canada, the study excluded Lake Michigan.

Activities list 2018 base year


20 years

($Millions of dollars)

50 years

($Millions of dollars)

Commercial fishing $227 $5 $10
recreational fishing $560 $12 $26
Recreational boating $7,291 $153 $333
Wildlife observation $218 $5 $10
Use of beaches and lake front $248 $5 $11
Total $8,544 $179 $390
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Table 1. Estimated current values ​​of affected activities in the Great Lakes in 20 and 50 years, by activity.2

Source: Fisheries and Oceans Canada staff calculations, Politics and Economics, Central and Arctic Region.

Environmental impact

Panoramic view of the calm lake

From an environmental point of view, the introduction of invasive carp into Canadian waters would represent a threat to native species and biodiversity in general.

Invasive carp:

  • the other lives
  • compete with native fish for food and habitat
  • act as carriers of diseases or parasites that could spread to native fish

Freshwater fisheries scientist Dr. Nick Mandrak and his colleagues at the University of Toronto have analyzed the characteristics of invasive carp to see how likely each species would be to survive in Canada.

They determined that if introduced, all four species would have a high chance of becoming established, and if that happens, there is little that can be done. He said: “We have done everything we can to assess the risks of invasive carp, and they are significant. Greater vigilance will now be necessary to keep them out of Canadian waters.”

Here’s what you can do to help

Silver carp exploding out of the water

Although the threat is real, invasive carp are not established in our Great Lakes. You can help keep invasive carp out of the Great Lakes:

  • Learn to identify the four different species of invasive carp. They are easily confused with native species and you will want to keep an eye out for the real thing.
  • If you think you have identified an invasive carp, report it online or using the Early Detection and Rapid Response Mapping System (EDDMapS) app.
  • Add the Invasive Carp Canada website to your favorites. It is your number one resource to learn about the biology, behavior, and current research and prevention technologies of invasive carp.

Learn about other invasives and how you can help exclude them from Ontario parks and protected areas at the Invasive Species Centre.