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Battling the Asian carp threat to the Great Lakes Region


Research surveillance techniques, specifically environmental DNA (eDNA) detection tools that are used to identify and monitor invasive species, have come to the forefront in the multi-state battle to prevent Asian carp from invading the Great Lakes. At risk is the future of one of the largest fresh water systems in the world and a $7 billion sport fishing industry. The eDNA detection tools represent an exciting new frontier in species detection.

GLOBES-IGERT Trainees Cameron Turner and Matt Barnes work with a team of researchers under the direction of Dr. David Lodge, GLOBES Co-PI and Director of the Center for Aquatic Conservation at the University of Notre Dame, to quantify the concentration of Asian carp eDNA in water samples that are collected during ongoing surveillance of the Chicago Sanitary and Shipping Canal through a monitoring agreement with the U.S. Army Corps of Engineers.

The canal is a man-made shipping link that connects the Mississippi River system to Lake Michigan. To overcome the well-known limitations of traditional fisheries sampling gear in situations where the target fish is rare (like the situation at an invasion front), the Lodge team employed environmental DNA, considered to be a non-traditional method. In early 2009, they adapted and improved the method in order to detect the eDNA of silver carp and big head carp, collectively referred to as Asian carps, in the Chicago canal. Environmental DNA refers to bits of tissue routinely left behind by all organisms. In the case of these fishes, the DNA could be contained in cells from multiple sources including slime, feces, and urine. Specifically, they identified and used species-specific molecular markers for silver carp and for bighead carp. These markers recognize sequences of DNA that occur only in silver carp or only in big head carp and not in any other species of organism.

Beginning in summer 2009, the Army Corps of Engineers began to financially support the use of the environmental DNA (eDNA) tool as potentially the best available technology to detect the presence of silver carp and bighead carp where they occur at low abundance. Since Notre Dame biologists first reported the presence of eDNA of Asian carp in the Chicago Sanitary and Ship Canal in late Fall 2009, the results have generated widespread interest and concern on the part of government officials, conservationists, and representatives of various industries as reported in the national media. In testimony before the Feb. 9, 2010 oversight hearing on “Asian Carp and the Great Lakes” before the U.S. House of Representatives Committee on Transportation and Infrastructure Subcommittee on Water Resources and Environment, Dr. Lodge said, “I am here to talk about the Chicago Sanitary and Ship Canal and the threat it poses as a conduit for the dispersal of potentially harmful species into the Great Lakes. The threats urgently at hand are silver carp and bighead carp, but the canal represents a potential highway to environmental havoc for many species that pose a high risk to both the Great Lakes and the Mississippi basins.”

Dr. Lodge’s written testimony was also included in a multi-state brief brought before the US Supreme Court against the State of Illinois seeking an injunction to close the canal. Although the Supreme Court refused to hear the case, efforts are ongoing to stop the invasion of Asian carp into the Great Lakes. In collaboration with The Nature Conservancy, the Lodge research team works to better understand the dynamics and sensitivity of eDNA in a variety of natural conditions thereby greatly improving eradication methods and prevention of invasive populations. In December 2009, a team of scientists from the U.S. Environmental Protection Agency was invited to observe and audit the methodology used to detect the presence of Asian carp in the Chicago canal from start to finish.

Their conclusion, in short, was to find a “high degree of confidence” in the eDNA methods employed. Research work on the part of GLOBES trainees Turner and Barnes seeks to further refine the eDNA detection method and to determine its future application to other species and ecosystems. GLOBES trainees are funded by an IGERT grant from the National Science Foundation. Dr. Jeffrey Feder is PI of the GLOBES (Global Linkages of Biology, Environment, and Society) at the University of Notre Dame.

Address Goals

Environmental DNA surveillance methods provide new weapons in the battle to detect and prevent invasive species. In the case of the Great Lakes and the threat of an invasion by Asian carp, they provide significant evidence on the urgent need for immediate action by management and policymakers.

In contrast to other surveillance methods, the environmental DNA (eDNA) method does not rely on direct observation of Asian carp to evaluate presence.

Laboratory and field studies using eDNA methods confirm that Asian carps can be detected in small volume water samples from sites that contain extremely low densities of carp. To date the Lodge research team has collected and analyzed hundreds of water samples from throughout the Chicago Sanitary and Shipping Canal (CSSC) region for both silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp. The eDNA approach to surveillance allows greater geographic coverage throughout the CSSC and connected waterways, and is more sensitive at detecting low abundance of fish than the methods currently employed.

Additionally, the ensuing national media coverage of the Asian carp threat and attention by many levels of government officials from local to international is a prime example of the demand for scientists trained in communication skills and prepared for rapid response to imminent crises in today’s world of high-profile environmental challenges. GLOBES fellows received a “real world” experience that keenly demonstrates the need for a multi-disciplinary mindset capable of translating scientific findings and expertise to varying constituencies, both private and public.

Biological invasions are the least reversible form of pollution. In contrast, most other forms of pollution—like the phosphorus pollution in the Great Lakes, the nitrogen and sulfur compounds of air pollution, heavy metals, and PCBs—degrade or get buried, and the problems they cause decline eventually. Once a population is established in Lake Michigan, it will continue to spread throughout the Great Lakes, and the damage to fisheries, recreation, and human health will grow exponentially over time.