Michigan is asking the public for new ideas to stop Asian carp from entering the Great Lakes. A prize is being offered to whoever comes up with a way to stop the fish, which would crowd out native fish and restrict recreational boating if allowed to enter the lakes. The amount of prize money to be offered and the number of possible winners is still being worked out by officials. The Michigan Legislature and Governor Rick Snyder allocated $1 million to develop the challenge beginning this summer in collaboration with InnoCentive.
Check out this article featured in Traverse, Northern Michigan’s Magazine for more information about the devastating effects of Asian carp.
This article was featured in the May 2010 issue of Traverse Magazine. Get your copy.
When you scope out the scenery from the middle of the 135th Street Bridge in Romeoville, Illinois—the bridge that spans the DesPlaines River and, just to the east, two canals that follow the river’s course—you can’t help but be awed by one of America’s epic industrial landscapes.
To the north, a Citgo refinery sprawls for a mile and a half through the flat river plain, a masterful and bewildering array of tanks and pipes and spindly fraction towers that rise like minarets of the industrial age. From a fat smokestack on this calm March morning, an exclamation point of steam, thick, monolithic and white as snow, gleams radiantly against the blue sky. To the south of the bridge another plant, this fronted by a tremendous pile of coal, pitch black, waiting to feed the power plant that squats here beside the waterways.
Then there are railroads—trains with a hundred cars and more come speeding by. One heads north, air horn blasting, metal wheels rumbling, and soon another heads south, tracing the canal’s edge to who knows where. The jewel of the neighborhood is just up around the bend toward Chicago, the Argonne National Laboratory, where America first learned to make electricity from radioactive elements.
Indeed, the river plain has evolved into a dramatic technological stage where modern and ancient converge, and as such is curiously fitting for another facility recently added here, one that you barely notice perched down on the cutstone bank of a century-old canal. This facility presents as just a gray metal pole building about the size of a doublewide, but like its neighbors it is also involved in an epic drama involving man and nature and, also like its neighbors, is in part a shrine to the principle of unintended consequences—in this case fish that escaped captivity and threaten to take over America’s two vast freshwater realms—the Great Lakes and the Mississippi River system.
Called the Chicago Sanitary and Ship Canal Aquatic Nuisance Species Dispersal Barriers, or “the fish barrier” for short, the little pole building and the electric current it shoots into the water here about 30 miles southwest of Chicago’s waterfront is all that prevents invasive varieties of Asian carp from swimming north to Lake Michigan. If the carp barrier fails and fish thrive in the Great Lakes, some people fear the carp could consume a huge percentage of the plankton that makes up the base of the food web, possibly dramatically reducing populations of small forage fish and ultimately reducing numbers of game fish like lake trout, salmon and smallmouth bass that Midwesterners have come to cherish. The impacts would not be limited to underwater, either. One variety of Asian carp, the silver carp, leaps from the water when disturbed by boat motors and has caused concussions, broken people’s jaws and in at least one case, knocked a jet skier unconscious.
If ever there was an environmental crisis that exploded like a slow-motion bomb, it is the invasion of Asian carp during the past 30-some years throughout the waterways of mid-America and now to the shores of Lake Michigan. But for a long time, the explosion was barely visible, hidden by the muddy river waters of the South.
Our nation’s Asian carp crisis began back in 1972 with bighead carp and 1973 with silver carp, when an Arkansas fish farmer imported the fish to clean catfish ponds. They were intended to swim through the water and filter out unwanted algae that affected the flavor of catfish, but there’s no evidence the strategy really worked. Adult fish consume up to 22 percent of their body weight in plankton each day. (Note to fact nerds: The widely reported 40 percent of body weight in plankton a day is wrong.) Silver carp commonly grow to about 20 pounds, bighead commonly to about 40 pounds, although world records are much larger. Catfish rearing is big business down south, so government even lent a hand, helping support research that spread the carp to farms within and beyond Arkansas.
Amid the loosely regulated environment and more carefree management practices of the 1970’s, the fish swam out of ponds into adjoining rivers. “You hear over and over that the fish escaped in the floods of the 90’s, but that’s not true. They got loose in the early 70’s, and by the floods of the 90’s, there were already tons of them out there,” says Duane Chapman, who knows more about Asian carp than perhaps anybody in the United States. As a researcher with the U.S. Geological Survey in Missouri, he has studied the carp for decades as they have invaded tributaries of the Mississippi River system, including the Missouri River, Ohio River and Illinois River.
With their natural predators, parasites and diseases left safely behind in Asia, the carp’s strengths were free to shine. First, they have a stunning ability to breed. A single mature female bighead can lay 200,000 or more eggs a year (one study recorded a female bighead that produced 750,000 eggs in one year), compared to say, a rainbow trout that might lay 3,000 eggs or a lake trout that might lay 10,000 eggs. And once hatched, Asian carp grow with astonishing speed, quickly becoming too large for predators to eat. A silver carp can grow to 12 inches in its first year. And the long rivers of the South presented fine nursery habitat.
When biologists talk about Asian carp, they use the term loosely to encompass four varieties of carp: the silver, bighead, grass and black. In China, where the fish originate, people also have an umbrella term for them—the fish are such a popular food and so integral to culture they are called “the four famous domestic fishes.”
And actually, the fish have become somewhat famous worldwide. The carp are so cheap to feed, grow so fast and have such a subtle taste that they have been exported to every continent except Australia and Antarctica—something that becomes important when evaluating their Great Lakes invasion possibilities (more on that later). In a 1995 study, bighead carp were ranked fourth in global commercial fish production, at 2.8 billion pounds. “They’re kind of the hamburger of food fish,” Chapman says.
Despite the umbrella terms, there are differences among the carps—the silver and bighead carps are filter feeders; grass carp eat vegetation; and black carp eat snails, clams and other creatures on the bottomlands. The biggest immediate threats to the Mississippi and Great Lakes are the silver and bighead. The black is not yet known to be reproducing in the wild (but it might be somewhere, Chapman cautions), and the grass has not proliferated to the point where it is taking over waterways. But biologists fear that both the grass and black have enough in common with the silver and bighead, notably their hardiness and reproduction prowess, that they pose a serious threat. Ironically, while the United States has been unable to control the population explosion of silver and bighead, their populations in China are collapsing in some places because of two familiar culprits: overfishing and habitat destruction.
In the United States, the fish didn’t really reveal themselves to be a problem for several years after introduction. “It’s very, very common for invasive species to go through several generations where they aren’t really able to do too much with population expansion,” Chapman says. “Then something happens. Maybe it’s critical mass, or something changes in the environment, but you hit this exponential growth phase.”
And that’s what happened with silver and bighead carp in the late 90’s. First bighead, then silver about five years later. “So that lag phase lasted 20 to 25 years,” he says. Relative to the Great Lakes, Chapman worries that if the fish successfully invade but do not become visible, people will become complacent about the threat, possibly for decades, while the fish have time to reach that point of exponential growth. “It’s very difficult to keep the public focused on an issue for that long,” he says.
Once the population explosion occurred in the Mississippi system, the fish began to move inexorably north. Commercial fishermen on the Mississippi complained that they would pull up nets with only Asian carp, and so many that the nets were too heavy to haul, so the fishing sites were abandoned. One big wakeup call came in 1999, when a fish kill in a Mississippi River backwater revealed 97 percent of the fish were Asian carp. Boaters complained that silver carp were leaping out of the water, and it was becoming dangerous to water ski or even drive a boat—for protection, some people have built cages over their boat’s steering area. A key problem is that carp habitat is often similar to that preferred for fishing and water skiing.
In 2002, Jerry Rasmussen, a fish biologist with the United States Fish and Wildlife Service, wrote a report titled “The Cal-Sag and Chicago Sanitary and Ship Canal: A Perspective on the Spread and Control of Selected Aquatic Nuisance Fish Species.” Rasmussen foretold with disturbing accuracy the situation in Chicago today: “… it is easy to speculate that the Asian carps will navigate the Cal-Sag and Chicago Sanitary and Ship Canal system with ease, and unless control measures are taken soon, they should easily find their way into Lake Michigan within 2 to 3 years.”
Last fall and winter, researchers say they proved the accuracy of Rasmussen’s predictions. Through a novel process called environmental DNA (eDNA for short) testing, a team from the University of Notre Dame found evidence of at least one silver carp in Lake Michigan near the mouth of the Calumet River and evidence of additional carp, both bighead and silver, in other parts of the Chicago waterway system close to Lake Michigan. The eDNA process involves sampling water and looking for DNA markers unique to Asian carp—fish leave shreds of DNA in fish slime, feces, and urine.
Some people have challenged the certainty of the data, given the newness of the procedure, but Phil Moy, a Wisconsin Sea Grant scientist and co-chair of the Great Lakes Aquatic Invasive Species Panel, says the “the chance of it being false positives is almost nonexistent.” In an independent technical review of the study and test procedures, scientists said the data should be considered “actionable”—meaning it’s solid enough to guide policy decisions. “If we didn’t have the eDNA technique, and were still relying on nets and electro-fishing as monitoring techniques, we probably wouldn’t even know they are at the barrier, let alone past it,” Moy says. The eDNA discoveries in late 2009 thrust the carp issue into the media like no other results have and convinced the government to put higher priority on stopping the invaders.
In a dramatic response in December 2009, when the electric fish barrier was partially shut down for maintenance, the government convened more than 400 people downstream of the barrier to help poison a 5.7-mile stretch of the Sanitary
and Ship Canal with Rotenone, a toxin that prevents oxygen uptake by organisms with gills. Crews collected 30,000
to 40,000 dead or surfaced fish that day, but only one was an Asian carp, a bighead. But a caveat: Asian carp generally don’t float to the top when they are poisoned, so researchers believe more than one carp was probably killed.
The eDNA findings also convinced Michigan and Wisconsin to ask the Supreme Court to force Chicago to immediately close the two locks on the waterway, the O’Brien lock and the Chicago River lock. The states first filed suit in the fall when eDNA showed evidence of carp near Lake Michigan and again this winter when a sampling showed evidence of a carp in Lake Michigan—but the court refused to close the locks.
Meanwhile, Michigan’s federal legislators Senator Debbie Stabenow and Representative Dave Camp have introduced companion legislation to force the locks’ closure, but the bills lie dormant. Even if the locks were to be closed, the fish could still migrate unimpeded up the Little Calumet River to Lake Michigan.
If the Notre Dame eDNA evidence is accurate, and the fish have made it to Lake Michigan, what does that mean? The question is obvious, but the answer is not. One of the biggest problems with invasion science is there are so many unknowns.
For starters, the carp would need adequate food. Some biologists speculate that zebra and quagga mussels have removed so much plankton from Lake Michigan that the Asian carp could not thrive. Chapman, however, feels the fish would adapt. He knows of a lake in Hungary with both zebra mussels and Asian carp, and the carp are doing well in the low-plankton environment. Researchers suspect the carp have changed their diet; one possibility is partially digested food called pseudofeces that’s produced by zebra mussels, which are very similar to quagga. Studies will be underway.
The fish also need the right water temperature. Lake Superior might be too cold, but the other Great Lakes would not present a problem—the carps’ homes are at the same latitude as the lakes. As for predators like lake trout and salmon, they would only have a shot at the carp during the earliest phases of the carps’ lives.
The carp also need the right habitat to reproduce—and this is where biologists see the greatest potential for keeping the population down if they do invade. The eggs from silver and bighead must drift, and in order to drift, they need to be laid in water that moves fast enough to keep them from sinking to the bottom for about 30 hours until they hatch. After the eggs hatch, the larvae continue to drift for about 70 to 80 hours until they can begin swimming. What this means is the carp need a river with an unimpeded flow of about 60 miles. If the river runs too short or the current too slack, the eggs and or larvae sink to the bottom and die.
In Lake Michigan, a half dozen rivers appear to meet these criteria. To stymie reproduction, one strategy would target those rivers with things like acoustic bubble barriers (a barrier that uses sound and a curtain of bubbles to drive fish away, which is safer than electrifying the water) in rivers where the fish could spawn. Chapman’s concern is, just as with the fish adapting to a new food source, carp might also be adaptable enough to hatch eggs in less-than-ideal conditions.
But Chapman also sees hope: “One thing we know is that these fish have been introduced all over the world,” he says. “And in no place have they been able to establish a population without approximately 60 miles of flowing water.” For there to be a big impact on the lake, a big population of carp is required, so biologists will launch a number of studies in coming months to determine if carp can reproduce in Lake Michigan tributaries, and to devise methods for interrupting that process.
But all of this is conjecture about an invasion that biologists concede is too complex to predict the results. “Speculating is very difficult,” says Dr. Dan O’Keefe, a fish biologist with Michigan Sea Grant, based near Grand Haven. He poses the question: Would anybody have thought that when zebra and quagga mussels invaded, they’d clarify the water so much we’d have cladophora blooms, and those blooms would give rise to botulism, and that round gobies—another invasive—would become infected, and birds would eat the gobies and get botulism too, and we’d have thousands of birds dying from botulism because of a mussel invasion?
“Perhaps changes due to Asian carp would not be this large, but they could be even larger—nobody can know,” O’Keefe says. “It’s best we don’t find out.”
O’Keefe’s tale raises a key message that fish biologists fear is being lost with all the focus on the Asian carp: The Chicago waterways allow many forms of life through, going both ways—from the big lake to the big river and vice versa. The zebra mussel, round goby and Eurasian ruffe all moved from Lake Michigan to the Mississippi here. And to be effective, we need a system that stops all of it, not just big fish heading to Lake Michigan. The electric barrier is too limited to achieve a comprehensive fix. Case in point: it had to be adjusted after it was built because the electric jolt was not effective on small fish, like say, juvenile Asian carp.
And the electric barrier has no effect at all on invasive molluscs larvae attached to a barge hull. Nor could it stop something really small, like the deadly fish virus hemorrhagic septicemia, which was transported from the East Coast to the Great Lakes and discovered in 2006. In a kind of sick irony, life moving through the system is only a problem of late because until now the canal waters were so toxic nothing could survive the 28-mile journey.
Such concerns about all aquatic life forms explain why fish biologists are nearly unified in their belief that America must re-establish the separation between the Great Lakes and the Mississippi River system that existed until the Sanitary and Ship Canal was built at the dawn of the 20th century. “But what we don’t have agreement on is how that will take place,” says Sea Grant’s Phil Moy.
Re-separating the Great Lakes system and the Mississippi system will be a monumental undertaking and the agreement that Moy refers to is not likely to come easily or cheaply. Barge operators have raised concerns that a system would add expense to their service. Tourist ferryboat operators worry that a barrier in the wrong place would kill their business. The Alliance for the Great Lakes, a Chicago-based Great Lakes advocacy group, is one of the only organizations to have published a rough plan for how to accomplish the holy grail of preserving both environment and business.
“This issue is not just about separating the Great Lakes and the Mississippi,” says Joel Brammeier, president of the group. “It’s about finding a better way to do business on water.” His point: there are water junctions all over the world where invasions must be stopped, and the methods developed here could be exported. “This city was built by people who looked at massive new infrastructure as a world of possibility, and that is where we are now. Chicago knows how to think big and build big. As long as we can keep in that mindset, we can solve this problem.”
Possible solutions being discussed include gigantic mechanisms that would lift barges over a permanent barrier, or locks that always drain water back to the original basin, or transferring cargo so that barges would never move between the two water systems (the surest way to prevent transfer of organisms that hitchhike on barge hulls).
But even the most optimistic observers say it could be 15 years before massive new infrastructure solutions would be in place. In the meantime, a multi-agency task force called the Asian Carp Workgroup has published a draft strategy that employs a collection of techniques to stop the advance: poisonings, a beefed up electric barrier, acoustic bubble barriers, netting, expanded commercial fishing. (After all, if there’s one thing humans are adept at it’s driving a species to extinction when it has commercial value.)
On Monday evening, in the third week of March, the harbor of Frankfort, Michigan is virtually empty, the dozens of charter fishing boats that ply Lake Michigan during tourist season still in dry dock. Twilight reflects pale blue in the water, and the placid scene feels a universe away from the industrial river plain in Romeoville, Illinios, that’s home to the electric fish barrier. But the nearly 100 people who file into the Garden Theater this evening are acutely aware of their tiny town’s connection to that place 200 miles to the south. They fear that if the barrier fails, Asian carp have the potential to decimate the big game fish of Lake Michigan and take down the charter fishing economic pillar of this community.
Speaking tonight are fish biologist Dr. Doug Workman, state representative Dan Scripps and Derek Bailey, tribal chair of the Grand Traverse Band of Ottawa and Chippewa Indians. Beyond just explaining the issue, a goal of the evening is motivating people to spread the word and write their representatives to convince them to shut the locks in Chicago as an interim emergency measure.
By coincidence, the meeting happens on the same day the Supreme Court has again rejected Michigan’s request to force Chicago to close the locks. One point that resonates with the crowd: how can the nation be sympathetic to Chicago’s $40 million barge and ferry business while putting an estimated $7 billion Great Lakes fishery at risk?
“This isn’t about jobs versus the environment,” Scripps says. “It’s about jobs versus jobs,”—a point reinforced by the fact that the local chamber of commerce has organized the meeting. Nobody mentions that even if the locks are closed, the fish could still swim through the Little Calumet River and that President Obama’s home district would flood in the next big rain.
Bailey is the last person to speak. The youthful, soft-spoken and thoughtful tribal chair with a ponytail to his waist begins by explaining the principle of seven generations, that decisions today should be made in the interest of children seven generations into the future. That principle has convinced the tribe to do what it can to stop the advance of the carp, he explains.
Bailey says he has an idea. He believes the Native American tribes in Michigan who signed the 1836 Treaty have a legal avenue that the states do not. In that treaty, the federal government agreed to be the trustee of natural resources for Native People. Allowing the carp to invade Lake Michigan would be a breach of that agreement. He wants to know if the community would support the tribes if they were to head down that path—tribes are cautious about suing the federal government. The people clap. It’s clear they’ll support anything that has even the remotest chance of stopping the advance of the Asian carp.
Jeff Smith is editor of Traverse, Northern Michigan’s Magazine | firstname.lastname@example.org.