Asian Carps
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Asian Carps

“Asian carps” refers to 4 species of carps (Bighead, Black, Grass, Silver) which are members of the cyprinid family and are related to several varieties of minnows. These carps are all native to the rivers, reservoirs and lakes in China and southern Russia. All 4 species have escaped into the wild in North America and 3 of these species have now established self-sustaining populations, particularly in the Mississippi waterway system, although Black Carp have likely established as well.

  • Asian carps prefer cool to moderate water temperatures like those found in the Great Lakes and reproduce rapidly

  • Asian carps can eat up to 40% of their body weight each day and can grow more than 25 cm in their 1st year and can reach 40kg and over a metre in length when matured

  • Bighead and Silver carp eat plankton, the very foundation of the aquatic food web and spread aggressively

  • Vibrations in the water excite Silver Carp causing them to jump up to 3 metres (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 injury to recreational users

 Illustration by Joseph Tomelleri of a bighead, black, grass, and silver carp

Asian Carps in North America

Asian carps were introduced to North America in the early 1970s for biological control of algae, plants and snails in aquaculture ponds. It is presumed that the Asian carps escaped into the Mississippi river basin from southern United States aquaculture facilities during flooding occurrences between the 1970s and 1990s. There are four types of Asian carp:

  • Bighead Carp

  • Black Carp

  • Grass Carp

  • Silver Carp

These fish are of concern because of the damage they could do to Canada’s ecological, recreational and economic environments should they become established in the Great Lakes. The two most damaging invasive carps, Bighead and Silver carps have progressively been moving northward in the Mississippi River, overtaking habitat and food sources from native fishes. Without proper prevention, it is anticipated that Asian carps will make their way into the Great Lakes, “It is expected that these invasive species would cause similar problems here in Canada if they became established in the Great Lakes – would cause problems and hardship for commercial fishers” (Becky Cudmore, Manager, DFO Asian Carp Program)

Silver Carp leaping out of the water as field workers barricade them


 Asian carps were introduced to North America for use in the aquaculture industry. The four species of Asian carp include Bighead, Black, Grass, and Silver carps. In Canada, Bighead and Grass carps were imported for the live food fish industry.

Flooding in the southern United States in the 1970s and onward may have resulted in Asian carp moving beyond their contained environments into open freshwater systems. Adapting quickly to the natural environment, two of the Asian carp species, Bighead and Silver carps (together termed bigheaded carps) began migrating northward through the Mississippi Basin. 

 1990 After the water receded following a major flood event in the Illinois River area, the number of dead Asian carps on the shoreline outnumbered all native species of fish 9 to 1. This was a warning that Asian carps had invaded and authorities realized there was a major problem.

 2003-04 Canada participated in two Asian carp summits held in Chicago to consider strategies to prevent the introduction of Asian carps into Lake Michigan.

Fisheries and Oceans Canada (DFO) conducted a risk assessment study to evaluate the likelihood of arrival, survival, reproduction, spread, and impact of Asian carps in Canadian waters. The study concluded that the risk was high in most parts of Canada, including the southern Great Lakes basin.

DFO science staff began ongoing participation in the development of the U.S. Asian Carp Control and Management Plan, and in a prevention subgroup.

 2005 As a result of the risk assessment, the Province of Ontario modifies regulations to ban the sale or possession of live Asian carps.

 2008 Canada initiated “border blitzes”, intercepting several shipments containing live Asian carp coming into Canada by air and road. Canadian officials have since worked with several partner organizations to provide training, equipment and protocols to help with this monitoring.

 2009 Asian carp DNA was discovered during monitoring exercises in the Chicago Sanitary and Ship Canal, 10 km from Lake Michigan. This indicated that bigheaded carps were much closer to the Great Lakes water basin than previously thought. During a scheduled shutdown for routine maintenance of the electrical barriers which control fish movement through that waterway, Canada contributed equipment and expertise toward containment efforts to prevent Asian carps from passing through the Chicago Sanitary and Ship Canal into the Great Lakes.

Development of an Asian Carp Control Strategy Framework was begun to set forth a series of short-term and long-term actions to control the spread of Bighead and Silver carps and prevent their introduction and establishment within the Great Lakes.

 2010 The Province of British Columbia banned the possession and sale of Asian carps.

Fisheries and Oceans Canada announced the launch of a Great Lakes Basin-wide “Bi-national Ecological Risk Assessment of Bigheaded Carps for the Great Lakes Basin”. This report identifies likely routes where Silver and Bighead carps could enter the Great Lakes and assists in the preparation of immediate, effective actions against emerging threats to Canadian waters. The study is led by Fisheries and Oceans Canada and coordinated by the Great Lakes Fishery Commission.

 2011 The Ontario Provincial and Federal governments collaborated in mock exercises to test the Ministry of Natural Resource and Forestry’s Rapid Response Framework and communication systems. These frameworks are designed to be used in the event that Asian carps were discovered in the Canadian Great Lakes. 

Fisheries and Oceans Canada and the Ontario Ministry of Natural Resources and Forestry officially sign on as members of the US-led Asian Carp Regional Coordinating Committee.

The Fisheries and Oceans Canada-led Bi-national Ecological Risk Assessment of Bigheaded Carps for the Great Lakes Basin is completed. Results provide scientifically defensible, peer-reviewed advice for determining best courses of action by both countries to reduce the probability of introduction of these species into the Great Lakes.

 2012 The Government of Canada announced that $17.5 million would be allocated over the next 5 years for the prevention, early warning, response and management control of Asian carps. Based on the funding, DFO initiated the development of a new Asian Carp Program.

Canada also continued to work closely with their American counterparts to develop an extensive early warning and monitoring system. “The Great Lakes is the largest freshwater system in the world and represents one of Canada’s most valuable assets,” added Minister Ashfield. “We are committed to working with our American counterparts to continue to protect the Great Lakes basin. Together these measures will go a long way toward our ultimate goal of stopping Asian carp from entering and becoming established in the Great Lakes.” The Honourable Keith Ashfield, P.C., M.P.

 2013 Fisheries and Oceans Canada confirm two separate captures of live Grass Carp, both near Dunnville, Ontario in the Grand River near Lake Erie. Response activities were undertaken by both Fisheries and Oceans Canada and the Ontario Ministry of Natural Resources and Forestry. Both Canadian specimens were confirmed to be sterile, leading to the conclusion that they were more likely stocked individuals.

This same year, the United States Geological Survey published a report showing evidence of reproducing Grass Carp in the Sandusky River in Ohio, a river that empties into Lake Erie.

Fisheries and Oceans Canada began work to assess the ecological risk of Grass Carp in the Great Lakes.

Fisheries and Oceans Canada researchers in Burlington also began developing and testing new methods for controlling the movements of live fishes using sound and water pressure curtains. Native fishes that share similar behaviour to Asian carps are used for testing purposes. 

 2014 The U.S. Army Corps of Engineers submitted a report to the U.S. Congress outlining alternatives to prevent Asian carp and other invasive species from transferring between the Great Lakes and Mississippi River basins. The GLMRIS Report included a comprehensive range of options and technologies available, along with estimated costs. According to the report, any impacts to Canada, even relatively minor ones, may require coordination with Canada.

Ontario proposed the Invasive Species Act to support the prevention, early detection, rapid response and eradication of invasive species in the province.

Quebec joined the Asian Carp Regional Coordinating Committee.

Fisheries and Oceans Canada completed construction of a new Asian Carp Laboratory in Burlington, Ontario at the Canadian Centre for Inland Waters. A second Fisheries and Oceans Canada laboratory in Winnipeg was enhanced to conduct eDNA analyses.


Image of lab work

Spread of Bighead and Silver Carp (1975 – Present)

Although the population of Bighead Carp in the Mississippi River basin is rapidly increasing in size and range, the rate of expansion is not well understood. In 2006, a study was carried out within the LaGrange Reach of the Illinois River, where populations of Bighead Carp have been documented since 1993. The study used radiotelemetry to document movements of Bighead Carp within the river. Radio transmitters were surgically implanted into several adult fish in June 2003 and May –July 2004. 

The mean movement rate for adult Bighead Carp was strong> 1.7km/day and one individual moved 163 km in 5 weeks. This indicates that Bighead Carp adults are capable of rapidly expanding their range, specifically in the spring and summer months. Downstream movement rates were 0.5 km/d higher than upstream movement rates and, as there was no difference in upstream and downstream movement rates occurring at high and low river flows, the authors attribute the difference to the carp swimming faster with the current. This study was the first to document the movement rates and patterns of Bighead Carp within the United States and shows that adults are capable of moving considerable distances in a short time.

Spread of bighead carp in the United States
Map courtesy of the United States Geological Survey