Taking back our waters
May 21, 2020
May 16-23, 2020 is National Invasive Species Awareness Week. From land to waterways, we at the U.S. Fish and Wildlife Service work alongside partners to prevent new invasions and combat the establishment of self-sustaining populations of invasive species, such as Asian carp.
Adult silver carp. Photo by USFWS.
Asian carp were originally imported from Southeast Asia to the southern United States in the 1970s as a biological control method for vegetation in man-made aquaculture ponds and wastewater treatment facilities. Flooding and accidental releases allowed these fish to escape into the Mississippi River system and migrate into the Missouri and Illinois Rivers. The Illinois River is connected to the Great Lakes by a manmade connection, known as the Chicago Sanitary and Ship Canal. By the early 1990s, two types of Asian carp, bighead carp and silver carp, had taken hold and were threatening to continue their migration farther north to the Great Lakes.
We strategically began work to keep them out of the Great Lakes more than a decade ago, because we saw a grave environmental danger. If a self-sustaining population of bighead or silver carp were to become established in the Great Lakes, it would hurt native fish populations and recreational opportunities alike. The four species of Asian carp found in the United States, which include grass carp and black carp, are all fast growing and prolific feeders that are able to out-compete native fish for food, as well as alter the underwater environment, rendering it is uninhabitable for other native plants and animals. Silver carp also jump out of the water when agitated by the sound of a boat motor, which poses a safety hazard to recreational boaters. Thus began our unified fight with the help of Great Lakes Restoration Initiative funds.
The past decade of collaboration across state and watershed boundaries has been vital due to the potential of Asian carp to disperse widely in open systems and negatively impact habitats on a landscape-level scale. We knew that fighting this fight alone, or even in parallel, would be a fruitless exercise. State governments, nonprofits and our fellow federal agencies, as well as tribal and international governments, have been vitally important in implementing management and control strategies on a national level.
We have served as co-chair of the Asian Carp Regional Coordinating Committee since late 2014. The committee represents the collaborative efforts of international, federal, state and municipal agencies to combat the spread of Asian carp into the Great Lakes. Throughout the past decade, the committee has provided oversight and coordination of interagency prevention activities through an annual Asian Carp Action Plan and complementary Monitoring and Response Plan. Along with our partners on the Asian Carp Regional Coordinating Committee and under the leadership of the U.S. Army Corps of Engineers, we assessed hotspots across the Great Lakes and Upper Mississippi Basin through the Great Lakes and Mississippi River Interbasin Study. The 2010 study identified 18 geographic locations where Asian carp and other invasive species could spread through aquatic pathways. In the past decade, we set out to remove these aquatic pathways of concern. We remain united through our actions to protect the Great Lakes, and the waterways of the United States and Canada, from invasive Asian carp.
Invasive species are notorious for creeping into waterways undetected. Catching the early invaders is key to preventing invasive species from gaining a foothold in a lake or waterway. With that in mind, we established the Whitney Genetics Lab in 2013 to fight the spread of water-borne disease and invasive species like Asian carp. This 5,800 square-foot, state-of-the-art research facility pushes the boundaries of genetic science. After only seven years in operation, the lab has processed more than 47,000 samples. Using a technique known as environmental DNA, or eDNA, we are currently processing water samples taken from across the Great Lakes Region to detect the presence of Asian carp genetic material. Patterns of positive eDNA findings in waterways over time can give managers clues about where the leading edges of the Asian carp populations are located. We also utilize mobile eDNA laboratories in the field to prepare samples near targeted collection sites. This not only reduces the expense associated with sampling, but also the time it takes to respond to positive findings. Since mobile testing began in 2013, we have used this technology to process more than 33,000 water samples from small tributaries to the greatest of lakes, including Lake Superior, Michigan, Erie and Huron. In addition to eDNA monitoring, the lab is also developing other genetic tools to identify invasive species and are building a reference DNA sequence database to support this work.
Holding the line
America’s roads, rails and rivers are major commercial routes for transporting goods across North America. Unfortunately, these key transportation networks are also convenient conduits for invasive species, including Asian carp. With this in mind, the U.S. Army Corps of Engineers built a series of electric dispersal barriers and other deterrents to slow the well-established Asian carp population in the lower three pools of the Illinois Waterway from moving north and getting closer to the confluence of Lake Michigan. Additionally, our crews spend more than 10,000 hours a year, monitoring and surveying the Illinois River in this same fight.
In 2012, we set out on our first of six barge studies, with the objective of determining if there was a potential for commercial barge traffic to facilitate fish passage beyond the electric dispersal barriers located within the Chicago Sanitary and Ship Canal. Through our research, in cooperation with the U.S. Army Corps of Engineers and the U.S. Geological Survey, we concluded that small free-swimming fish can become inadvertently trapped between barges and transported for substantial distances. It is also possible for barges moving downstream, away from Lake Michigan, to temporarily cause a decrease in the electric charge in the canal and cause water in the canal to reverse direction and flow upstream, toward Lake Michigan. The takeaway is that these combined effects could increase the risk of small fish being able to move upstream through the electric dispersal barriers in place to restrict Asian carp migration. After countless hours in the field studying barge traffic, fluid mechanics and the effectiveness of the electrical dispersal barriers, we are now able to inform the work of our partners in the development of solutions.
We continue to keep our eye on the prize and stay focused on keeping Asian carp out of the Great Lakes. A great example of this is our ongoing successes on the Missouri River. In 2014, our Columbia Fish and Wildlife Conservation Office team in Missouri designed and launched the Magna Carpa, a special vessel that removes all sizes of silver carp from the water. A special net, which moves on winches in and out of the water like wings, used in conjunction with electric fields stuns the invasive fish and then scoops them up. In the five years that the Magna Carpa has been in action, our team has captured more than 200 tons of Asian carp. Currently, the vessel is optimized to reliably remove seven tons a day - that’s the equivalent weight of more than four automobiles!
We have worked for more than a decade as part of interagency activities to prevent, manage, and control Asian carp. We will continue to work with our partners to conduct research and identify, develop and implement methods that will help us fight the threat of Asian carp.