RoveretoDon't+Worry?

Invasive Species : Asian Carp in the Mississippi River and the Threat They Pose to the Great Lakes


=

 * Top Left, Large:** A satellite image of the Great Lakes. **Top Left, Small:** Fishermen pulling in a net full of carp. **Top Right:** A school of carp "flying." **Center:** A horror film-like poster highlighting the danger of the invasive Asian carp. **Lower Right:** A graph displaying the massive increase in catch rate of three species of Asian carp from 1990 to 2000. **Lower Left:** An image illustrating both the population density and unique behavior of the carp in the Mississippi River.=====

The Problem:
The Mississippi River and many of its tributaries have become inundated with a flood of epic proportions. This deluge is not one made of water, but of fish, of sheer biomass. Since the mid-1970s, several species of carp originating from Eurasia, known collectively as Asian Carp in the United States, have been breeding in the Mississippi and its tributaries in large numbers, with reproduction rates that far surpass the reproduction rates of any other fish species in these rivers. They are ravenous, consuming up to 40% of their weight in algae and plankton a day. In areas of rivers where their population is relatively small, individual bighead carp can grow to weigh upwards of 80 lbs. Carp are filter-feeders, meaning they survive by filtering algae and plankton out of the water they swim through. The algae and plankton are needed either directly or indirectly by all the native fish in the river, thus endangering the survival of these original Mississippi River-dwellers by crowding them out of their food source as well as space in the river.

Silver Carp are a direct physical danger to humans as well. Silver carp are especially skittish, and the sound of a boat motor or any similar water disturbance nearby will cause them to launch themselves, en masse, up to 10 ft. out of the water. Even the relatively large carp, sometimes weighing nearly 50 lbs. have been reported launching from the water’s surface. These flying carp have caused numerous injuries, both minor and severe, to fishermen and scientists studying the problem. Bighead, grass, and silver carp are the major species that have become well-established in the Mississippi River System, despite their introduction less than 40 years ago. Since then, the populations of these Asian carp, especially bighead and silver carp, have skyrocketed. The range of these carp is coming ever closer to the Great Lakes.

The History:
The Asian carp problem began in the 1970s, when silver carp and bighead carp were imported into the United States to control the algae growth in both aquaculture (fish farming) and municipal treatment facilities for waste water. It is not known exactly how, but some of these fish escaped from captivity soon after they were brought to the U.S. Since that time, they have thrived in the Mississippi River, as the climate of the river basin is nearly identical to those of their native regions in Eurasia. Massive flooding in the area in 1993 exacerbated the problem, as this water provided more prime areas for spawning grounds, leading to exponential growth in the carp populations in the following years. Their numbers are difficult to pin down, as only the ones that are caught are counted, yet research into breeding grounds and carp spawns have shown that there may be as many as 2 million invasive carp in the Illinois River alone, a tributary of the Mississippi. Bighead and Silver carp have been found far up the Illinois River, the connection between the Mississippi and Lake Michigan, which then leaves all the Great Lakes vulnerable.

Threat to Biodiversity and the Great Lakes Ecosystem:
The number of Asian carp is unlikely to decline or even slow its growth anytime soon, as, unlike the native fish species which breed at most twice a year, carp can breed up to four times in a single year, greatly outpacing the reproduction of indigenous fish. This massive population, along with their diet, is proving a major threat to many local species, including large fish such as the Mississippi paddlefish. The paddle fish depends almost entirely on plankton to survive, and having to compete with droves of carp for a shrinking food source has caused the Mississippi paddlefish to become a rare sight in the water over the past few years. This fish is listed as a vulnerable species, but very soon it will probably become endangered, and it might already qualify for the designation.

These fish are not only a danger to the biodiversity in the river systems, they could cause the entire Mississippi River ecosystem to collapse, as there are already indications that the algae in the river right now are not enough to sustain the current populations, as increasing numbers of caught carp and indigenous fish are emaciated. One study on the effect the carp population has had on the health of some indigenous species of fish has shown that the body conditions of two species, the gizzard shad and bigmouth buffalo, have decreased significantly, by 7% and 5% respectively, from 2000 to 2006. These carp could consume the majority of algae and plankton in the river, and with no other food source to turn to, could die off in large numbers, as would the native fish in turn.

If these carp make it into the Great Lakes, an ecosystem already made fragile by another invasive species, the zebra mussel, an even greater problem than the one in the Mississippi River may arise. The Great Lakes hold an especially fragile population of lake sturgeon, a massive fish that can live over 100 years and grow over 9 feet in length with proper nutrition and time. Since the zebra mussel invasion depleted most of the zooplankton in the lakes, the sturgeon's food source, sturgeon rarely approach their upper age or size limit. If carp become established in Lake Michigan, the lake sturgeon could become an endangered species. The Great Lakes contain 22% of the world’s fresh surface water, and approximately 85% of the U.S.’s fresh surface water. Destruction of the Great Lakes ecosystems could disrupt or reduce the water supply to tens of millions of people and cripple interconnected ecosystems on the coasts.

Current and Possible Solutions:
Several methods exist for the containment of the invasive carp to the Mississippi, but few if any will impact the current population of these fish. Laws have been put in place that make the sale of silver or bighead carp as live bait illegal, as well as the sale of live silver or bighead carp to consumers. This is so these fish cannot be released into any unaffected waterway, either intentionally or accidentally. Local governments and organizations are pushing for more people to eat these fish, as many people see the carp as "bad fish" and refuse to eat them once caught. Also, several counties of states along the Mississippi are implementing a catch and kill policy, meaning once a carp is caught, it cannot be released and must be killed. In the upper part of the Illinois River, an electric barrier in the water has been constructed which should, in theory, deter these carp from entering Lake Michigan, by passing pulses of direct current into the water. Until this permanent barrier was built, a temporary one was put in place that functioned under the same principles. However, a large bighead carp was caught past this barrier, although this is not indicative of a population past the barrier.

One possible long-term solution would be incentives for fishing companies that catch Asian carp, as well as for restaurants that serve Asian carp as a major portion of the menu and food companies that incorporate carp into their products. Another option that would not remove the population problem in the Mississippi, but would keep the population in check would be the exportation of the invasive carp. The latter option is already in implementation, as these fish are being sold to several nations, including Israel. This is not only helpful from an ecological standpoint, but helpful economically as well.

Works Cited:
Bradley, Tahman. "Massive Asian Carp Found Near Lake Michigan." __ABC News__. 4 Dec. 2009. Accessed 12 Sept. 2010 Web <[]>

"Flying Carp." __Monster Fish__. National Geographic Channel. Aug. 2010.

Irons, K.S., Koel, T.M., and Ratcliff, Eric. USGS. "Asian Carp Invasion of the Upper Mississippi River System" Nov. 2000. Accessed 13 Sept., 2010. Web <[]>

Peer-Reviewed Journal Article: Irons, K. S., Sass, G. G., McClelland, M. A. and Stafford, J. D. (2007), "Reduced condition factor of two native fish species coincident with invasion of non-native Asian carps in the Illinois River, U.S.A. Is this evidence for competition and reduced fitness?". Journal of Fish Biology, 71: 258–273. doi: 10.1111/j.1095-8649.2007.01670.x Accessed 13 Sept., 2010. Wiley Online Library. <[]>

//Monster Fish.// National Geographic. "Flying Carp: Facts." 2010. Accessed 13 Sept., 2010. Web <[]>

Snyder, S.J. "Carp-Pocalypse: The Great Lakes Asian Carp Invasion Begins?" __Time News Feed__. 24 Jun. 2010. Accessed 13 Sept. 2010 Web <[]>

Interesting Links:
Video clip of National Geographic show on the Asian Carp : []

A CNN Money video on the containment efforts on the Illinois River: []

Pictures:
Great Lakes Map: [| http://3917583460384624402-a-fieldmuseum-org-s-sites.googlegroups.com/a/fieldmuseum.org/pwillink/asian-carp-in-chicago-faqs/Great%20Lakes%20satellite%20image.jpg?attachauth=ANoY7cqH-vZ5QNDDRJ-_EuF4Pyl1p8mlNGjXHSuqY3DeH02UDvBpUq6mmPDN_dlwXu0GlUMhVUNznr2z6IhK6XFHpAXJbjww7S9gis5wczmlXDnPwf62ReLB4jsltTZSkCKVKGk9Qe8S6UJ4-IWbOrcZUUWWp84BR8pvrjfZULHbRhxTo9ZiSie5umO_l6SFqpUo3bSTZeR36dWE42QHZWRzYlgqfGoFKzA8un3VhGXiFfMUZqLDE3GcXaitcOdUiWnOM77j05DN&attredirects=0]

Net Full of Carp: []

Flying Carp: [| http://www.nwf.org/Wildlife/What-We-Do/Invasive-Species/Asian-Carp.aspx]

Attack of the Flying Carp! : []

Carp Population Graph : []

Carp School and Fishing Boat : []