The term Asian carp can be confusing, because it is generally applied to a group of related species, including the bighead (Hypophthalmichthys nobilis), silver (Hypophthalmichthys molitrix), grass (Ctenopharyngodon idella), and black carp (Mylopharyngodon piceus). These fish can get quite large, up to 110 pounds, and they eat copious amounts of plankton. They are related to goldfish, Koi, and the common carp (Cyprinus carpio). The latter has already been established as an invasive species across most of North America for more than a century.
Read more about what is being done to control carp, about the extent of carp in the Illinois river, and identifying carp by gene sequencing - by clicking on the title or picture.
Few fish can inspire as much horror as the Asian carp (well, except perhaps the dreaded candiru).
But except for a few well publicized collisions with leaping fish, the Asian carp is rarely dangerous to human beings. Instead, ecologists warn that the Asian carp can wreak havoc on aquatic food chains by vacuuming up plankton and damaging submerged vegetation.
Asian carp are officially listed as invasive species in the U.S., and they are widespread throughout the Mississippi River Basin. Only a few individuals have been found in the Great Lakes so far, and fisheries managers are drawing a line in the sand to keep it that way.
This week, the Obama administration unveiled the 2012 Asian Carp Control Strategy Framework, with an attached budget of $51.5 million, reports the Associated Press. Agents will be stepping up monitoring and efforts to catch the fish in rivers that connect to the Great Lakes.
Officials will also be testing out scent-based lures for the Asian carp, an acoustic water gun that is hoped to repel them, and improved electric barriers and surveillance at locks.
Including this current commitment, the U.S. government has spent $156.5 million on keeping bighead and silver Asian carp out of the Great Lakes, reports the AP. The fish are known to be living about 55 miles away from the lakes in the Illinois River. Environmentalists have called for sealing off connections between the water systems, but others have warned such measures could cause flooding and restrict shipping traffic.
Meanwhile, the Army Corps of Engineers is working on a broader study that aims to propose long-term solutions. Results are expected in 2015.
Asian carp are more recent invaders, having worked their way through the Mississippi over the past few decades. They are thought to have escaped from aquaculture operations in the South in the 1970s, where they were imported to clean ponds.
Asian carp are generally considered better eating than common carp, and they are prized as food in Asia, where they have been farmed for more than 1,000 years. As part of efforts to control their spread in the U.S., a growing number of anglers and biologists are trying to convince people to harvest them.
Can the beefy fish be contained? Only time will tell. Invasive species represent one of several serious threats to freshwater ecosystems, in addition to dams, diversions, pollution, and other problems. Systems that are already stressed are less likely to fight off invaders than healthy communities. The Great Lakes have been under siege for a long time.
Find out exactly where Asian carp have been spotted on the United States Geological Survey’s Nonindigenous Aquatic Species website.
Article appeared Feb 24, 2012 on http://voices.nationalgeographic.com/2012/02/24/asian-carp-freshwater-sp...
Brian Clark Howard is a writer and editor with NationalGeographic.com. He was formerly an editor at The Daily Green and E/The Environmental Magazine and has contributed to many publications, including TheAtlantic.com, FastCompany.com, MailOnline.com, PopularMechanics.com, Yahoo!, MSN and elsewhere. His latest book, with Kevin Shea, is Build Your Own Small Wind Power System.
Here's a related article about the extent of Asian carp in the Illinois river:
Apr. 21, 2012 — Asian carp, that large, invasive fish known for leaping out of a river into boats when startled, now make up more than 60 percent of the total fish biomass in one of Illinois' major river systems, a research team led by Southern Illinois University Carbondale has found.
But the team members' advice for controlling the species goes something like this: "If you can't beat 'em, eat 'em."
James Garvey, director of the Fisheries and Illinois Aquaculture Center at SIU Carbondale, has led the effort that for the last 18 months to quantify and solve the Asian carp problem in the state's rivers. In 2010, the University received a contract worth $1.1 million to find ways to eradicate the fish through commercial fishing and other means.
The grant from the Illinois Department of Natural Resources funded multiple studies and resulted in a report released last week titled "Fishing Down the Bighead and Silver Carps: Reducing the Risk of Invasion to the Great Lakes."
The report includes several major findings and strategies. Along with establishing that the carp now make up the majority of living tissue in the main channel of the Illinois River, it also found that eating the tasty, healthy, high-protein fish is plausible approach to greatly reducing its numbers.
"We basically found that harvesting this fish for commercial purposes will work, and that there is a market among consumers for this fish," Garvey said. "There are other challenges, such as processing the fish, but we believe it can be done."
The research represents the most comprehensive estimate of a main-channel fish assemblage in history using research-grade, down-looking hydroacoustics coupled with other sampling techniques, Garvey said. The study also looked at mortality and reproductive potential, as well as the quality of the meat and potential commercial market for the fish.
"To date, fishing is the only feasible and effective control mechanism in the Illinois River," the report states. "We conducted research to determine how marketing plus incentives might help facilitate fishing as an effective way to reduce Asian carp while enhancing sustainable harvest of native fishes."
Asian carp, a large, bony fish, are present in the upper and lower portions of the Mississippi River, the lower Missouri River, the Illinois River and Ohio River. Several varieties -- including the bighead and the silver, which can grow to 100 pounds and leap into the air -- are present in Illinois waterways.
Populations of these fishes are growing dense in the lower and middle Illinois.
River and both species are approaching the Chicago Area Waterway System (CAWS) and the defensive electrical barrier set up there to stop it. The team believes the downriver source populations of the fish will continue to send individuals upstream to challenge the CAWS and ultimately the Great Lakes until their numbers are reduced.
During the last decade, the state has taken action to prevent the fish from becoming prevalent in the Great Lakes fisheries. To that end, Garvey said, many government agencies are dedicating resources to studying and fixing the problem.
Although the major concern regarding the carps' entry into Illinois waterways and the Great Lakes is the fear that it will hurt the populations of native fish, Garvey said their team found -- at least so far -- that isn't true.
"We've seen no extinctions of native species, although numbers of some important commercial species, such as big mouth buffalo fish and food source fish such as the gizzard shad, have declined," Garvey said.
To conduct the study, researchers spent weeks aboard The Shovelnose, the University's 27-foot research vessel outfitted with sophisticated equipment. Two or three crewmembers piloted the boat up and down the Illinois and Mississippi rivers, traveling more than 2,100 miles while conducting hydro-acoustic surveys and catching, tagging and releasing carp for tracking.
The hydro-acoustic surveys revealed that about 2,800 Asian carp live in each mile. Tagging the fish also showed the larger fish moved hundreds of miles up and down the river, though the researchers aren't yet sure why.
"As is always the case with science, you often have more questions than answers," Garvey said. "We saw a large movement corresponding with the floods last year, which was fascinating. But we don't what exactly triggered them to do that. And we don't know if they are moving somewhere to spawn. We need to do more research."
Along with Garvey, SIU Carbondale researchers on the project include: Jesse Trushenski, assistant professor of zoology and also animal science, food and nutrition; Greg Whitledge, associate professor of zoology; Brian C. Small, associate professor of animal science, food and nutrition; Silvia Secchi, assistant professor of agribusiness economics; David Glover, a post-doctorate fellow with the Fisheries and Illinois Aquaculture Center; and Sara J. Trip, a former researcher with the Fisheries and Illinois Aquaculture Center.
Secchi's work focused on the problem from an ecologically economic point of view. Secchi looked at the potential of different strategies for turning the Asian carp biomass into something valuable such as food source for humans or fishmeal for supplementing fish feed or fertilizers.
The fish is high in protein and healthy polyunsaturated fatty acids. Most fish also were low in contaminates. It has a mild flavor and is among one of the healthier fish for consumption, given its plankton feeding habits. In China, where the head of the big head variety is used to make soup, the fish has been hunted to near eradication.
Secchi's research showed that a market exists for Asian carp, although the infrastructure in the region for capturing, processing, and transporting the fish is poorly developed. China currently is importing whole, flash-frozen Asian carp, but demand appears to depend on exporting large-bodied fish in large quantities, with an apparent premium on bighead carp.
The team also sees an opportunity in converting Asian carp into fishmeal, although additional infrastructure is needed for an appropriate processing facility. In addition to exporting the fish for human consumption and making it into fishmeal, marketing research suggested that U.S. consumers across a wide range of demographics are willing to try Asian carp and would be interested in purchasing a value-added product such as fish cakes, particularly if marketed as locally produced, the report stated. Again, however, the primary hurdle for developing such products is a lack of infrastructure in the region, not public perception.
Garvey said even with a concerted effort to commercially remove the fish from Illinois waterways, it is likely it would remain there in substantial numbers. Such an outcome, however, might be beneficial in that it would sustain a new industry based on the fish's harvest.
Along with SIU Carbondale, researchers from Illinois Natural History Survey, the University of Illinois and Michigan State University collaborated on the project.
The executive summary of the report can be found here: http://asiancarp.us/documents/EXECCARP2011.pdf
The above story is based on materials provided by Southern Illinois University Carbondale.
Gene Sequencing Can Identify Invasive Carp
A project to map the microbes present in the digestive systems of fish species holds promise for monitoring the presence of Asian carp in Chicago area waterways and ultimately preventing their spread, according to a study published in Nature's ISME Journal. The work, funded through the U.S. Environmental Protection Agency Great Lakes Restoration Initiative, is being conducted by researchers from the University of Illinois at Urbana-Champaign and the U.S. Geological Survey (USGS).
Asian carp is a term used to refer to several invasive fish species including silver, bighead and black carp. Bighead carp and silver carp have already invaded much of the Mississippi River basin, where they compete for food with native species and dominate aquatic communities. Bighead carp and silver carp are considered one of the most severe aquatic invasive species threats facing the Great Lakes today, according to the Asian Carp Regional Coordinating Committee (ACRCC). The ACRCC is coordinating the efforts of federal, state, local and private resource management agencies to develop an Asian carp control program. Efforts to control the fish include research to understand their physiology and behavior and how they differ from that of native species, with an eye toward developing effective monitoring and management systems.
Gut microbiota -- the microbial communities present in the digestive tracts of living things -- are unique, according to Wen-Tso Liu, co-author of the study and a professor of civil and environmental engineering at Illinois. For that reason, careful analysis of fish gut microbiota can reveal host-specific biomarkers shed in fish feces that indicate the presence of a specific species, promising the development of precise monitoring systems. Since fish feces are plentiful in waterways, monitoring could be easier than with techniques that have focused on detecting the DNA of the targeted species in sloughed-off skin tissue, Liu says.
The researchers used a next-generation gene sequencing technology called 16S pyrosequencing, which focuses on the 16S rRNA gene sequences, to analyze the gut microbiota of the invasive silver carp and the native gizzard shad. They successfully discovered potential biomarkers for silver carp and are working to refine them, Liu says.
In addition, the research illuminated some important similarities and differences in the species. For example, he says, gizzard shad harbor microbial communities that are 10 times more diverse than that of silver carp, showing that their digestive processes are significantly more complicated. The researchers also discovered a common food-source microbe, which proves that the fish compete for the same food.
"This is why invasive species can be dangerous," he says. "They can eat the same food, and if the invasive species consumes more food, then the native species can be out-competed and their population will start to decline, leading to ecological disaster."
On the strength of these findings, the researchers are beginning an extensive project to confirm their findings in the fish species in the Chicago River -- approximately 50 different ones -- in order to map their gut microbiota and develop biomarkers for each species. The results will lead to a precise monitoring methodology, but the benefits will likely extend further, Liu says.
"There is a lot more beyond just monitoring," Liu says. "We will also learn more about the diversity of fish, their diets, how their diets are related to their gut microbiota and how they metabolize inside the gut."
The above story is based on materials provided by University of Illinois College of Engineering.