The Threat of Asian Carps to the Great Lakes

The full effects and consequences of aquatic invasive species sometimes take decades to emerge. The Bi-national Ecological Risk Assessment of Bigheaded Carps (DFO, 2012)1 determined that following the arrival of Asian carps, it would take 7 years for the impacts to be realized. Fisheries and Oceans Canada used this information to conduct a Socio-Economic Impact Assessment (DFO, 2014)2 to better understand the impacts of an Asian carp establishment in the Great Lakes. The study uses 2011 as the base year, and an adjusted base of 2018 from which to consider the 20 year and 50 year impacts. For the purposes of estimating the impact to Canada, the study excluded Lake Michigan. 


Reference year: 2018

(millions of $)

20 years

(billions of $)

50 years

(billions of $)

Commercial Fishing

$ 227

$ 5

$ 10

Recreational Fishing

$ 560

$ 12

$ 26

Recreational Boating

$ 7,291

$ 153

$ 333

Wildlife Viewing

$ 218

$ 5

$ 10

Beaches and Lakefront Use

$ 248

$ 5

$ 11


$ 8,544

$ 179

$ 390

Table 1. Estimated Present Values of Affected Activities in the Great Lakes in 20 and 50 Years by Activity.2

Source: Calculations by Fisheries and Oceans Canada staff, Policy and Economic Studies Branch, Central and Arctic Region.

In order to estimate the risk to each activity, it was assumed that without added prevention, Asian carps will arrive, establish a population, survive and spread due to the availability of suitable food, compatible lake temperatures and spawning habitats, and high productivity embayments in the Great Lakes basin.

Commercial Fishing

The Commercial Fishing Industry depends heavily on the health and ecological state of the Great Lakes. The total value of the Commercial Fisheries in the Great Lakes during 2011 was over $33 million dollars. The presence of Asian carp would have multiple impacts, including:

  • Increased costs and decreased revenues for commercial harvesters.
  • Small prey fish of commercially fished species would be impacted through direct consumption by Asian carp.
  • Increased competition for food resources with young and mature native species.
  • This decrease in revenue would in turn reduce the level of gross profits and thereby create a circular flow of impact.

From a demand perspective, the commercial fishing sector would also be adversely affected as the quality of native species fished would be expected to reduce as total population numbers decline. As the total number of catchable fish decline, commercial fisheries will need to adjust harvesting methods for smaller sized native fish species. This reduction in fish size and quality will decrease the demand of Great Lakes’ fish as a food source all over the world.






Global total

Landings (lb)


Yellow and White Perch






Rainbow Smelt











Lake Whitefish






White Bass





Others *












Landed values


Yellow and White Perch

$ 15,188,370

$ 887,012

$ 285,436

$ 2,416

$ 16,363,235

Rainbow Smelt

$ 1,359,120

$ 73

$ 0

$ 0

$ 1,359,193


$ 9,039,586

$ 444,159

$ 57,113

$ 1,217

$ 9,542,074

Lake Whitefish

$ 717,572

$ 3,223,094

$ 72,497

$ 246,538

$ 4,259,701

White Bass

$ 1,432,657

$ 909

$ 89

$ 0

$ 1,433,655

Others *

$ 36,961

$ 195,631

$ 167,512

$ 209,183

$ 609,287


$ 27,774,266

$ 4,750,877

$ 582.648

$ 459.354

$ 33,567,145

Table 2. Landings and Landed Value of Commercial Fishing in the Great Lakes in 2011, by Species and by Lake 2


Note: * Includes American Eel, Bigmouth Buffalo, Black Crappie, Bowfin, Brown Bullhead, Burbot, Channel Catfish, Chinook Salmon, Cisco, Common Carp, Freshwater Drum, Gizzard Shad, Lake Trout, Lepomis, Moxostoma, Mudpuppy, Northern Pike, Oncorhynchus, Pink Salmon, Pomoxis, Quillback, Rainbow Trout, Rock Bass, Round Whitefish, Sea Lamprey, Suckers, White Sucker.

Recreational Activities

The presence of Asian carp in the Great Lakes would damage recreational fishing activities in a variety of ways, as shown in the flow chart below. If recreational catch rates were reduced by a decrease in native fish populations, there would be reduced angling activity and correspondingly, less disposable income spent on this recreational activity. Anglers contribute a large amount of money to the provincial government via fishing licenses, as well as, contributing to other sectors of the economy while on fishing excursions. Reduced recreational fishing and related activities will have economic impacts on other businesses and livelihoods which depend on the continuation and development of this sector.

Asian carps may also discourage recreational water use though direct harm to people and property. Silver Carp are known toexcite at the sound of boat motors, causing them to leap out of the water, possibly injuring water-skiers or landing in boats causing damage to property and injuries to boaters. There have also been incidents of Silver Carp breaking fishing rods, windshields and other equipment. In addition, once the carp land in the boat, they leave slime, blood, and excrement. These potential damages from jumping Silver Carp would also raise operational and maintenance costs to boat owners, such as repairs and installation of protective equipment.

Other major activities that would be negatively impacted by an Asian Carp establishment in Canadian waters is summarized in Table 3. The threats associated with Asian carps, as well as the estimated value that is at risk over 20 and 50 year periods in the Great Lakes are listed. The estimated values indicate what consumers would be expected to spend in each of these categories. It is anticipated that there would be some relocation of these expenses by resident/non-resident Canadians to other sectors due to the expected damage to these activities following an establishment of these invasive fishes (the values exclude respective consumer surplus and tourism).

Primary activity




Estimated value

20 years

50 years


Silver carp bounces out of the water

Damage to boats and navigation equipment

Increase in operating and maintenance costs

109 billion dollars

$ 237.3 billion


Reduction of participation

Wildlife watching

Increase in the number of Cladophora algal carpets in the Great Lakes, mainly along the shores

Reduced water quality

Obstacles to activities and opportunities for observation

$ 3.5 billion

7.5 billion dollars

Human health concerns

Reduction of participation

Use of beaches and lakeshores

Increase in the number of Cladophora algal carpets in the Great Lakes, mainly along the shores

Obstacles to activities taking place on beaches and lakeshores

Decrease in property values ​​and redistribution of expenses to other sectors

$ 5.2 billion

$ 11.3 billion

Table 3. Summary of threats to significant activities and respective costs in the Great Lakes basin 2

Cladophora: a green algae commonly found in the Great Lakes which grows on hard substrates and the lake bottom and becomes detached throughout the summer.

Total Economic Valuation of the Great Lakes

The Great Lakes basin has proven to be a very valuable resource to the Canadian economy in multiple ways. The basin is directly linked to numerous industries, all of which would be greatly impacted if the ecological state of the lakes were compromised. The most recent estimates of the value of economic contributions of activities in and around the Great Lakes basin is in the amount of $13,800,000 contributed to the Canadian economy.

The Great Lakes basin provides invaluable services to society with maintained ecosystem health and biodiversity. Those intrinsic values however, are difficult to quantify because they are much more intangible than other benefits such as commercial fish harvesting (Krantzberg, 2006). Flowchart 3 illustrates this number in greater detail and displays the distribution throughout different industries and sectors of the economy.

Social and Cultural Value of the Great Lakes

It is expected that recreational and cultural activities in Canada will experience similar negative impacts as those seen in Illinois and the Chicago Area Waterways should Asian carps establish in the Great Lakes. More than 1.5 million recreational boaters utilize the Great Lakes water system every year. The ecological impact that Asian carps would have on the Great Lakes, would likely result in significant declines in the industries, jobs and recreations that depend upon them. The decline in recreation related activities could also have a direct impact on Ontario’s reputation as a destination for outdoor recreation tourists, including purchasers of vacation homes.

Kayaking on river

First Nations communities have inhabited the shores of the Great Lakes for a very long time and cultivated a unique relationship with the rivers and lakes of the basin. There are currently approximately 75 First Nation communities inhabiting the coasts of the Great Lakes, with many more living within the surrounding areas. Hundreds of these communities occupying the Great Lakes region are engaged in fishing activities and many rely on subsistence fisheries for food and cultural reasons.3 Natural resources such as fish, are harvested by more than 70% of northern Aboriginal adults and >96% of those do so for subsistence purposes.4  The disruption of these fisheries by the invasion of non-native aquatic species could severely disrupt the ability of these groups to sustain their livelihoods and culture. Other concerns with the potential degradation of the Great Lakes quality include4:

  • Loss of biodiversity may cause loss of Aboriginal Knowledge related to specific species should they become extinct
  • Economic losses for First Nation communities due to the reduction of commercial fishing
  • Degradation of fish populations threatening food security and thereby traditional First Nation diets. Diet (and income supplementation) is especially important for residents in remote northern locations because of the high costs to transport goods and the limited employment opportunities.
  • Loss of culturally or spiritually significant sites
  • Gaining access to traditional fishing activities may be impaired and may increase costs of subsistence harvesting and thereby costs of living in the areas.
  • There may be increased level of competition among First Nation communities and with recreational and commercial harvesters for fewer native fish species.

First Nations groups play a key decision-making role regarding Great Lakes issues, and are consulted about resource development.

The Great Lakes provide considerable subsistence, social, cultural, and spiritual benefits to regional residents

and contribute significantly to the economy as a whole:

  • Socially, the Lakes’ beaches and shorelines provide a “sense of place” and a unique source of opportunity for research and educational activities that result in a better understanding of the ecology. 
  • Harvesters of Great Lakes’ freshwater fish species and the communities involved in the harvests have long realized the importance of these resources to their communities, both for preserving traditional values and for subsistence purposes.  
  • Great Lakes beaches and coasts provide a unique source of community pride, as they encourage diversified recreational activities. The beaches and coasts are a key public perception measure of environmental quality.
  • Freshwater fisheries have contributed substantially to the preservation of traditional Aboriginal lifestyles in the region. Fish harvesting is one of the primary economic activities which provide a viable livelihood to support Aboriginal family ties and traditions and it is therefore important for social and cultural reasons. 
  • Due to the inherent compatibility of the fisheries with traditional indigenous livelihoods, participation in this industry allows First Nation harvesters to participate in the modern economy without losing their cultural identity.
  • The investment in the freshwater commercial fishery contributes to the community, as in some northern communities, commercial fishing equipment is being used to supplement family income.  
  • The social impacts of commercial fishing are significant in terms of both employment and for cultural reasons. These non-economic cultural benefits are not only substantial, but may even exceed the benefits of subsistence as a food source.



1.  Bi-national Ecological Risk Assessment of Bigheaded Carps (DFO, 2012)

2.  Socio-Economic Impact of the Presence of Asian Carp in the Great Lakes Basin (DFO, 2014)

3.  Assembly of First Nations – Impacts of Pollution on Great Lakes Fisheries Discussion Paper (

4.  Climate Change, Health, and Vulnerability in Canadian Northern Aboriginal Communities (Furgal et al., Environmental Health Perspectives, 2006)