The Mississippi's Asian Carp Crisis

Asian carp have become an invasive species in the Mississippi River, threatening native fish populations and the fishing industry. The carp were initially introduced to the United States in the 1960s and 1970s to feed on algae in aquaculture ponds, but they quickly spread into the wild, establishing themselves firmly in the Mississippi River basin. Silver carp, in particular, have become a major concern, with their presence linked to a decline in sport fish populations in the river. Various measures, including electric barriers and government subsidies for carp consumption, have been implemented to contain and control the spread of Asian carp, but their effectiveness has been limited. With Asian carp firmly established in the Mississippi River, experts are now focused on managing their numbers and preventing their invasion of other waterways, such as the Great Lakes.

Silver carp are a huge threat to fisheries in the Great Lakes

The large size of silver carp, which can exceed 100 lbs and four feet in length, and their feeding habits pose a significant risk to native fish populations in the Great Lakes. Silver carp feed on small plants and animals in the water, called plankton, and their presence could disrupt aquatic food webs and the $7 billion Great Lakes fishery. Researchers estimate that it would only take 10 breeding pairs to inundate the ecosystem.

To prevent the spread of silver carp into the Great Lakes, various measures have been implemented. Electric barriers have been constructed in canals connecting the Mississippi River Basin to the Great Lakes Basin, such as the Chicago Sanitary and Ship Canal. The US Army Corps of Engineers has also developed a $1 billion plan to strengthen these barriers.

In addition to physical barriers, there have been efforts to create consumer markets for silver carp to manage their numbers. However, the development of a US market for carp faces challenges due to the fish's bony structure and Americans' general distaste for fish. Despite these efforts, officials and researchers acknowledge that completely stopping the invasion of silver carp into the Great Lakes may be impossible.

While Chicago's water pollution may have contributed to slowing down the movement of silver carp towards the Great Lakes, this is only a temporary solution. As water quality improvement efforts progress, the chemical barrier created by the pollution may disappear, allowing silver carp to move upstream. Overall, the presence of silver carp in the Mississippi River and their potential invasion of the Great Lakes pose a significant ecological and economic threat that requires urgent attention and comprehensive management strategies.

Electric barriers are being used to prevent the spread of carp

Asian carp have invaded the Mississippi River basin, with bighead and silver carp being the most common species. These carp are non-native to the United States, having been introduced in the 1970s to feed on algae in aquaculture ponds. They have since spread rapidly, threatening native fish populations, commercial fishing, and human safety.

To prevent the spread of Asian carp from the Mississippi River to other bodies of water, electric barriers have been implemented in various locations. The Chicago Sanitary and Ship Canal (CSSC), which connects the Mississippi River basin to the Great Lakes basin, is a major point of concern. The U.S. Army Corps of Engineers has constructed electric barriers in this canal to deter the movement of carp. These barriers create an electrical field in the water that discourages fish from crossing while still allowing commercial vessels to pass through.

The electric barriers in the CSSC are composed of steel electrodes secured to the bottom of the canal and controlled from an adjacent building. The electrodes generate a direct current (DC) pulse, forming an electric field that prevents fish migration. This technology has been effective in preventing Asian carp from entering the Great Lakes for over 15 years, preserving the health of this valuable fishery.

However, there are challenges and limitations to the electric barrier approach. One issue is the risk of other invasive species, particularly invertebrates, which may not be impacted by electric barriers. A study by Reuben Keller of Loyola University Chicago found that even at electrical charges 400% higher than the barrier level, no invertebrate organisms died. This highlights the need for additional measures to prevent the spread of invertebrates between watersheds.

Furthermore, optimizing electric barrier operations requires detailed knowledge of Asian carp physiology, including their tolerance to electric fields and burst swim speeds. The Electric Power Research Institute (ERDC) is conducting research to gather this information and improve barrier design, placement, and operation.

In conclusion, electric barriers are a critical tool in preventing the spread of Asian carp from the Mississippi River to other water bodies, especially the Great Lakes. While these barriers have been effective, ongoing research and improvements are necessary to address limitations and ensure the protection of aquatic ecosystems.

Sport fish numbers have declined in areas of the Mississippi River infested with Asian carp

Asian carp have become an invasive species in the Mississippi River basin. The fish were initially brought to the United States in the 1970s to feed on algae in aquaculture ponds. However, when they were released into the wild, they spread rapidly and now pose a significant ecological threat, particularly the silver carp variant.

A study released in November 2019 has confirmed the link between the presence of Asian carp and the decline of sport fish in the Mississippi River. The study, led by fisheries biologist John Chick, analyzed Corps data on fish populations between 1994 and 2013. It found that sport fish numbers declined by about 30% in two carp-infested areas on the Mississippi River and one on the Illinois River. In contrast, sport fish populations grew by nearly 35% in three sections of the Mississippi upstream where the carp were not present.

The study focused on silver carp, which are more abundant in the Upper Mississippi than bighead carp. It suggested that sport fish are losing out during their early life stages when they depend on plankton, which the carp are consuming in large quantities. Other factors such as flooding, water temperatures, and sediment pollution were considered, but none had a significant impact on the sport fish trends in the Upper Mississippi.

The findings add to the growing body of evidence that Asian carp are out-competing native sport fish species prized by anglers, such as yellow perch, bluegill, and black and white crappie. The decline in sport fish numbers has sparked concerns about the threat posed by Asian carp to the native ecosystem and the fishing industry. Efforts to manage and control the carp population have been ongoing, including the construction of electric barriers and the development of consumer markets for silver carp.

The creation of consumer markets for silver carp has been suggested as a potential solution to manage their numbers. However, the development of a US market for carp faces challenges due to the bony nature of the fish and general American distaste for fish. Despite these challenges, some states, such as Kentucky, Tennessee, and Illinois, have provided subsidies to support carp harvest and the creation of processing plants.

The US government has recognised Asian carp as an invasive species

Asian carp, including black carp, grass carp, bighead carp, and silver carp, are recognised as an invasive species by the US government. These carp species were imported to the US for use in aquaculture ponds in the 1970s. However, through flooding and accidental releases, they escaped into the Mississippi River system, where they have firmly established a home.

The US Fish and Wildlife Service (Service) has listed bighead, black, and silver carp species as injurious wildlife under the Lacey Act. This listing aims to protect humans, native wildlife, and wildlife resources from the purposeful or accidental introduction of Asian carp into aquatic ecosystems. The Service has also initiated an injurious wildlife evaluation on black carp and is working to prevent the spread of Asian carp in the Mississippi and Ohio River basins.

The US Geological Survey (USGS) also recognises the invasive nature of Asian carp and is conducting research focused on early detection, risk assessment, and the development of control tools and strategies. The goal is to prevent the establishment of Asian carp in the Great Lakes and reduce their impacts in the Mississippi River Basin and elsewhere.

The US government, through the Wildlife and Sport Fish Restoration program, is financing efforts to control Asian carp. States like Kentucky have dedicated funds towards research and monitoring programs to limit the spread of Asian carp and mitigate their negative impacts on native fish species and industries such as recreation, tourism, and sport fishing.

In summary, the US government acknowledges the ecological and socio-economic threats posed by Asian carp and is actively working to manage and control their presence in US waterways, particularly in the Mississippi River Basin.

The US Army Corps of Engineers is developing a $1 billion plan to manage carp populations

Asian carp have become a major nuisance in the Mississippi River Basin. The US Army Corps of Engineers is developing a $1 billion plan, also known as the Brandon Road Interbasin Project, to manage carp populations by preventing their entry into the Great Lakes. The project will include the construction of a high-tech suite of barricades, including an electric barrier, a bubble wall, sound blasts, and a flushing lock, at the Brandon Road Lock and Dam in Joliet, Illinois. The goal is to stop the invasive carp, specifically bighead, silver, and black carp, from entering the Great Lakes and causing further damage to the region's ecosystem and economy.

The project is expected to take a minimum of six to eight years to complete once construction begins. The federal government will contribute 90% of the cost, with the remaining 10% split between Michigan and Illinois. The states have already approved the necessary funding.

Invasive carp, which were introduced to the southern United States in the 1970s, have established wild populations in the Mississippi River Basin. They consume vast amounts of phytoplankton, the foundation of the lakes' ecosystem, and reproduce rapidly, outcompeting native fish species. Researchers have warned that the continued upstream trajectory of carp could have devastating consequences for the entire Great Lakes ecosystem and the region's $20 billion boating and fishing industries.

Efforts to manage carp populations in the Mississippi River Basin have included the construction of electric barriers and the development of consumer markets for carp meat. However, these measures have had limited success, and invasive carp continue to pose a significant threat to the region's fisheries and ecosystems. The US Army Corps of Engineers' $1 billion plan is a critical step towards preventing further damage and protecting the Great Lakes and surrounding areas.

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