This fish species has cost U.S. authorities over $200 million to prevent its invasion.
The “Invasive” Fish Species in Canadian and U.S. Waters
In the 1970s, Americans introduced an Asian fish species into fish farms in the southern United States. This fish is the Asian carp. Initially, farmers intended to use carp to clean the ponds and lakes for catfish farming, as well as to promote their health. Carp are filter feeders, which means they consume food by filtering particles and organic matter from the water by opening their mouths wide. This was also an ideal method for water filtration in fish farms at that time.
In 1970, Americans imported this Asian species into farms to improve water quality. (Photo: NYTimes)
Asian carp is the common English term for several carp species widely found and farmed in various parts of Asia, including China, Japan, North Korea, and Vietnam. They are a common food source in the daily diets of these regions, with the highest production levels globally.
However, following a major flood, two carp species—the bighead and silver carp—escaped into the Mississippi River basin. At that time, locals believed these carp could serve as a food source.
The species imported to the U.S. at that time was Asian carp. (Photo: NYTimes)
In 1994, a severe flood hit Illinois. When the waters receded, it was shocking to discover that the number of dead Asian carp was nine times greater than that of local fish species. At this point, many questioned how Asian carp could migrate so far.
By 2002, the “nightmare” for U.S. authorities officially began as Asian carp proliferated rapidly, severely disrupting the habitats of native aquatic species. Asian carp are known for their excellent adaptability to new environments. Besides being strong swimmers and adept at evading nets, they are omnivorous, capable of consuming up to 40% of their body weight in food. Typically ranging from 50 to 90 cm in length and weighing over 50 kg, Asian carp deplete large amounts of food, including other aquatic species, decimating local fish populations along their migration routes and destroying the ecosystems they invade.
Each Asian carp can spawn up to 2 million eggs in a single reproductive cycle, allowing this species to grow rapidly into large schools of hundreds. To prevent this fish from invading Lake Michigan, the first electric barrier was installed there, followed by two additional barriers in 2009 and 2011.
Asian carp have rapidly invaded many regions of the U.S. and have even reached Canada. (Photo: NYTimes)
After over 30 years, this invasive fish from Asia has spread to waterways in states like Minnesota, Wisconsin, and Michigan in the west; New York and Pennsylvania in the east; Illinois, Indiana, and Ohio in the south; and as far as Ontario in the north. Asian carp have invaded the Great Lakes, consuming up to one-fifth of the zooplankton in these lakes, threatening the $4 billion per year fishing and tourism industry in the Great Lakes.
The Fish That Keeps U.S. Authorities Awake at Night
For many, Asian carp truly represent a “monster” in the waters. With their voracious appetite, they can grow over 100 cm in size. They are aggressive fish, with many individuals weighing between 28 to over 45 kg and living up to 80 years. They leap out of the water in large numbers whenever they hear boat engines. They can jump as high as 3 meters when the water is disturbed.
Many boating groups have been surprised by schools of Asian carp leaping into their boats, “attacking” those who have disturbed the water surface. In 2014, the National Wildlife Federation issued warnings about the danger posed by Asian carp jumping into boats and putting people at risk. Even the Illinois Natural History Survey had to cover the propellers and control systems of research vessels with nets to prevent attacks from these fish.
Asian carp can jump as high as 3 meters when the water is disturbed. (Photo: NYTimes)
According to warnings from the Illinois Department of Natural Resources, since the arrival and invasion of Asian carp, they have had to seal off access to the Great Lakes to prevent the destruction of the entire flora and fauna in the largest freshwater area in the U.S. They installed electric barriers at the Chicago River entrance to “block 100% of the chances of aggressive immigrants entering Lake Michigan.” However, Asian carp have managed to bypass these electric barriers. Subsequently, authorities planned to create “bottlenecks” at both ends of the waterway connecting the Illinois River to the Chicago River.
Yet, experts from the Illinois Chamber of Commerce argue that closing the canal, which allows shipping traffic 24 hours a day, would cause significant economic damage. Transportation costs via road and rail would increase, while the shipping industry would face losses of about $8 billion per year. Thus, preventing the migration of Asian carp has become an urgent issue that keeps U.S. authorities awake at night.
Spending Millions to Combat the Invasive Fish
Local residents have tried various methods like netting, fishing, and even electrofishing, yet none have been effective in curbing the rise of Asian carp.
Americans have employed numerous methods to eradicate this fish, but none have halted its population growth. (Photo: NYTimes)
Other cost-effective approaches have also been considered, such as producing carp sandwich products to eliminate this species. Additionally, scientists have proposed introducing toxins into waters where they detect Asian carp DNA.
In 2003-2004, the U.S. and Canada collaborated on strategies to prevent Asian carp from invading Lake Michigan. In 2005, Ontario province banned the farming of invasive species, including Asian carp, but continued to allow the import of dead carp into the province. In 2008, Canada had to implement a “border control” to strictly regulate shipments of live Asian carp by road and air. In 2010, British Columbia province banned the possession and sale of Asian carp.
Over $388 million has been spent by U.S. authorities in the fight against Asian carp. (Photo: NYTimes)
In reality, since 2010, more than $388 million has been spent combating Asian carp, including the development of water-pressing guns, but these fish have quickly adapted to withstand the pressure from these guns.
This species is banned in Michigan and Minnesota; in Wisconsin, it can only be used for research purposes. However, five other states in the Great Lakes region—Illinois, Indiana, Ohio, Pennsylvania, and New York—still allow their use with special permits.
