How Asian carp could soon take over the Great Lakes — and how they could be stopped 

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click to enlarge Silver carp jumping in the Fox River. - ASIAN CARP REGIONAL COORDINATING COMMITTEE
  • Asian Carp Regional Coordinating Committee
  • Silver carp jumping in the Fox River.

Peabody and Lodge eventually stopped communicating and the two ended up in a downtown Chicago federal courtroom in early September 2010. They were both called as witnesses in the federal lawsuit brought by the neighboring states. In addition to lock closures, the states sued to force the Army Corps to expedite a congressionally ordered study of what it will take to permanently reconstruct the natural barrier between the Great Lakes and the Mississippi basin that the Chicago canal destroyed. When Peabody took the stand, he looked mildly agitated. "Never in my worst nightmares or wildest imagination did I think that a fish would so dominate my time and attention, because you don't think of the Corps of Engineers doing that," he told me later. "You think of us as managing water resource infrastructure and building things and fighting floods and doing that kind of stuff."

During his day in court, Peabody talked about his doubts that positive DNA samples meant the presence of live fish, and he had a fish expert ally in the courtroom in Charlie Wooley, the deputy regional director of the U.S. Fish and Wildlife Service. Wooley testified that the federal government and state of Illinois had gone to extraordinary lengths to try to follow up on the positive DNA samples with evidence of actual fish. They hunted for the fish with nets, electroshockers and barrels of poison. And all they had to show for it was that single bighead carp above the barrier, and a single bighead carp in the waters just below the barrier — the fish killed in the December 2009 poisoning.

"The traditional methods allow us to go out and sample large areas very effectively, very efficiently in a relatively short period of time," Wooley testified. "They are tried and true."

Lodge countered on the witness stand that those traditional fish sampling tools are effective at capturing only 1 percent of a fish population on a river the size of the Chicago canal. That means if small numbers of Asian carp lurked among tens of thousands of fish, odds are they would never turn up in a net or float to the surface if shocked. Asian carp, unlike many other fish species, also have a tendency to sink when poisoned. All this, Lodge has long argued, is precisely what makes DNA surveillance so powerful. But it's only as powerful as the trust you put in it.

"Continuing to try to use the traditional tools to detect the presence of rare or of very sparse populations is like saying: 'You know, even though we've got an MRI machine, I'm going to try and detect your cancer with a physical exam; I don't really understand what this MRI machine is doing, so I'm not going to believe it. I'm going to poke you with my fingers and figure out whether you've got cancer or not,'" he said in later interview.

Lodge was shaking as he ate from a bag of M&Ms after his testimony. He looked as if he had been the one on trial. The judge sided with the Army Corps and refused to issue an emergency order to shut the locks.

In early 2014, the Army Corps finally released a 10,000-page plan to permanently plug the canal to re-separate the two watersheds, a project that would require extensive sewage treatment upgrades because much of Chicago's treated waste would once again flow into Lake Michigan. The agency said the project, which would include a transfer station to move barge cargo over the barrier, would take decades to construct and cost as much as $18 billion — a schedule and price tag critics contend is wildly overblown. An engineering study funded by a group representing the Great Lakes region's mayors and governors, in fact, concluded it could be done for as little as $4.25 billion and a barrier could be in place in a matter of years, not decades.

The project remained on hold as of 2016, and its opponents are confident it never will happen. "I've been lobbying 25 years on behalf of industry," said Mark Biel, the executive director of the Chemical Industry Council of Illinois. "I'm pretty good at killing bills and ideas that people come up with, and this one has all the elements you'd need." Biel then listed those elements: the time it would take to accomplish; and the cost; the legal, regulatory, and political hurdles tied to sending at least some of Chicago's treated wastewater back into Lake Michigan. "This is not going to happen in my lifetime," the 51-year-old said. "And I don't plan on dying anytime soon."

Peter Annin, a former Newsweek correspondent and author who also previously worked with Lodge at Notre Dame, takes a longer view. He expects pressure to patch the breach between the basins will surge every time a new invasive species is found heading for the canal — whether it's swimming toward the Great Lakes or out of them, and into the rest of the continent. "This is not about Asian carp," Annin said. "This is about two artificially connected watersheds that many people argue never should have been connected."

The DNA evidence that Asian carp are swimming in Lake Michigan has mounted in recent years. It turned up some 200 miles north of Chicago in the waters of Wisconsin's Door Peninsula in 2013. It turned up in 2014 in an inland river in the state of Michigan, one that flows into Lake Michigan. It also turned up in late 2014 in the Chicago River just about a block from the lakeshore. But these microscopic flecks, this genetic "smoke," is all that researchers have found since the one and only Asian carp was plucked from waters above the barrier in 2010. The lack of fish flesh does not matter to Lodge's colleague Chadderton, who has likened the genetic evidence to that of a murder scene. "If it was a single fingerprint on the murder weapon and in the house where the crime occurred, you might ask the question: Well, maybe not? But the reality is, we've got fingerprints all over the crime scene," Chadderton said. "They're on the body. They're on the knife. ... They're smeared all over the place and they're on the handle of the door into the house. It's just like, come on people...the reality is the body of the evidence says we're dealing with live fish!"

Yet for now, the electric barrier is the only defense between the Asian carp-infested Mississippi basin and the Lake Michigan shoreline, and this should make no one feel comfortable. In early 2014, I obtained from the Fish and Wildlife Service a video taken by an underwater camera at the barrier several months earlier. Just one three-minute clip revealed dozens of little fish swimming upstream through the swath of electrified water. Lab tests conducted on a scale model said this was not possible with the voltage the barrier is operating at, but nobody before had ever bothered to drop a sonar-like camera in the water to see what might actually be in the canal.

The Army Corps brass remain nonplussed.

"Those aren't carp," Peabody's replacement, Brigadier General Margaret Burcham, told me in early 2014 in a conference room overlooking the downtown Chicago River — the very stretch of river that the migrating carp would pass through on their way into Lake Michigan, a mile upstream. Burcham isn't a fish expert; she has a graduate degree in computer science. Actual fishery experts weren't nearly as confident in what Burcham claimed to see — or, more specifically, claimed to not see.

"You can identify that they are fish. You can identify that they're moving — you can see that," Aaron Woldt, Fish and Wildlife's deputy assistant regional director for fisheries, told me. "But you can't tell [which] species."

The day an Army Corps general becomes convinced that an Asian carp invasion of the Great Lakes is under way — the day the fish regularly start turning up in nets above the electric barrier — is also a day it will probably be too late to do anything about it.

A tiny private fish pond in Missouri offers a distressing glimpse of what might be in store for the Great Lakes. The owner had stocked his personal fishing hole with catfish, bass, and bluegills. He was pumping it full of fish food, yet the fish appeared to be starving. So in early 2010 he called in a pond consultant.

"They came out with electrofishing gear, caught some fish and looked at them," the Geological Survey's Chapman said. "The fish were emaciated and he didn't know why. He said, 'There's something wrong here. We need to start over again.' They brought in rotenone and completely killed the pond."

Over the next week, the rotting carcasses of about 300 bighead carp surfaced. The smallest were 20 pounds. The big ones were a border collie-sized 35 pounds. "They looked like submarines coming out of the water," said Chapman, who arrived on the scene in time to watch the last of the dead specimens surfacing. "They'd breach!"

Poisoned Asian carp, Chapman explained, are different from many fish species in that they typically don't float to the surface unless the water is warm enough for gases to build up in their bellies, a process that can take a week. Or it may never happen if the poisoning occurs in cold weather, as was the case during the December 2009 Chicago canal poisoning.

It turned out that a decade earlier the previous property owner had stocked the tiny pond with a colony of bighead carp, one that eventually flourished right under the nose of the new owner, who had smelled trouble — but couldn't see a thing.

The biological bombshell that arrived at an Auburn University laboratory in 2009 came in the tiniest of packages — a cardboard box about the size of a paperback book. Inside it were several plastic tubes that contained flecks so small that they were invisible. Lab workers tipped these tubes into a solution that was as innocuous looking as a glass of water. It was anything but. In it floated a designer "poison" potent enough to eradicate an entire fish population.

The concoction, which held a specially modified fish gene built in a high-security laboratory on the Australian island of Tasmania, was placed into Petri dishes thick with E. coli bacteria and then dosed with a chemical that allowed the bacteria to absorb the genetic material. As the fast-reproducing E. coli numbers then exploded, copies of the gene replicated right along with it, with two new genes emerging each time a bacteria cell split. In a matter of hours the Auburn biologists had untold millions of E. coli, each carrying a strand of the manmade genetic code. And each of those strands held the power to take a species' collective sex drive and throw it in reverse, to turn sexual reproduction from a life-sparking act into a life-snuffing one.

It does so by adding a twist in the DNA so a fish implanted with the gene can produce only male offspring. The concept, called the "daughterless gene," is devilishly clever: a developing carp turns female only after an enzyme transforms the male hormone androgen into the female hormone estrogen. This gene blocks production of that enzyme, so the embryonic fish cannot make the early-life transformation from male to female. The idea is that if you plant enough of these daughterless fish into a lake or river for a sustained period, it's just a matter of time until it runs out of females to carry on a population. The fish breed themselves to oblivion.

click to enlarge Carp fry. - COURTESY RON THRESHER
  • Courtesy Ron Thresher
  • Carp fry.

It is no surprise this anti-carp technology was pioneered in Australia, a continent ravaged by invasive common carp that were imported by fish farmers. Those fish eventually — as almost always goes the story — escaped their containment ponds in floodwaters. It happened in the 1970s, right around the time Asian carp got loose in the United States. And as is the case with Asian carp in some stretches of river in the Mississippi basin — North America's largest — common carp now account for as many as 90 percent of the fish in some areas of the Murray-Darling basin, Australia's largest river system.

Ron Thresher, an American who pioneered the DNA-based pest control at a research center in Tasmania, Australia, explained to me on a tour of his lab that the genes he works with are species-specific and pose no measurable risk to the public or any other type of fish or organism. Still, the lab's security was extraordinary. To prevent any of the specimens carrying the gene from escaping into the wild, the lab windows were sledgehammer-proof. The floors near the doors were raised in a manner so no water — or fish — could float out if a tank burst. The walls were waterproof to a level that they could contain all the water in all the aquariums holding the genetically manipulated fish. Pipes from the lab didn't drain to the local sewer system. They led to a boiler for sterilization. If that boiler failed, there was a twin backup.

An obvious worry is that if just one of these fish implanted with the daughterless gene were set loose in the wild the gene could, eventually, spread across the globe and ultimately eradicate all females of the targeted species in a manner that would doom it to extinction. But Thresher said his team specifically designed their carp gene so that once it reaches the third generation, the fish that carry it only automatically generate males in half of their offspring. The other half of their progeny is half male and half female. The gene's impact would be halved similarly in the next generation, and so on, all in a manner that its effect on any fish population's sex ratio would disappear over time. This, Thresher explained, means hatchery-raised stocks of the daughterless fish would have to be planted for multiple generations to knock out a local population.

(Thresher said it is in fact possible to design a gene that ensures all-male progeny in every subsequent generation in a manner that could spark an extinction. "In theory, the release of a single carrier of one of these could doom a population. Not surprisingly, there is considerable debate about the risk," he told me. "We deliberately went for our approach because it is inherently much safer and we thought it wise to walk before one runs, in terms of recombinant genes to manage an invasive pest.")

After Thresher proved the gene worked in a type of fast-reproducing minnow in his lab, the next step was to figure out how to do the same thing with common carp, a much more daunting project given the larger size of the fish and the fact that it can take them years to reach sexual maturity. This means that tracking the gene down through several generations requires the better part of a decade, or more. A carp experiment similar to the one done on minnows in Thresher's lab also had to be scaled up from aquariums to ponds to see if the genetically modified fish could woo normal females in a more natural setting; the gene is useless, after all, if their carriers fail to get it into the next generation.

Thresher found a partner in Auburn's Rex Dunham, who in 2009 cleared the paperwork with his university to take delivery of Thresher's carp-eliminating gene. By early 2015 he was preparing to produce a third generation of daughterless carp at a gated research facility just north of the Auburn campus in eastern Alabama, about two hours south of Atlanta. The largest, most sexually matured fish — all males — were already swimming inside a fenced-in fish pond inside a barbed wire-capped chain-link fence that pulsed with low-voltage electricity to keep out potential predators like raccoons. The pond was also further covered with fine black netting to keep birds from plucking a fish from the water and lifting it off alive. The pond drained through a pipe with a screen on it. That pipe drained into a lower pond that drained through a sieve too fine for a large fish to flush through. That pond, in turn, flowed into a reservoir that had been purposely stocked with predator fish in case fish from ponds and tanks above somehow made it that far. Dunham called the whole setup "zealous," but it was clear he, like Thresher, takes the security issue seriously.

Dunham received about $100,000 from the Australians to conduct early research with his carp, but by the time I visited all that funding had dried up and he was doing the work basically for free. He said he was motivated by the mess invasive species have made across the globe — common carp in Australia; pythons in Florida; Asian carp in the rivers of his home state of Illinois.

"To have the potential to rectify our past environmental mistakes, to me, it's just intriguing and exciting that we could go back and do that," he said. "There are very few proven ways to go back and fix your mistakes, and the potential here is to eradicate a nuisance fish species, without poisoning a river or a lake or harming other fish. To me, that's an ethical thing to do."

Thresher was quick to acknowledge the potential for political backlash for planting daughterless fish in the wild and said he is happy to leave it up to the politicians to decide whether, when, where and how to deploy such a genetic tool. It's a decision that may take center stage sooner than people expect. Thresher predicts genetic solutions to invasive species problems would be "widely available" by the early 2020s, and he wasn't talking just carp. "The basic technology, once it's up and running," he said, "I think will be applicable to a wide range of things."

Mussels included? "Mussels included."

This has Russ Van Herick intrigued, and not a little wary. He heads a think tank funded by the Great Lakes states to develop creative solutions to some of the lakes' most vexing problems, and that has him thinking about how to use — or not use — a DNA-based eradication tool that he, too, is convinced is on the horizon. He wonders who will make the decision to deploy it. In the 1960s the state of Michigan decided on its own to plant exotic salmon, even though it was clear at the time the fish would not stay contained in Michigan waters. Would a single Great Lakes state today try to act on its own and release a manmade gene in a similar fashion? If not, would it take a unanimous vote by all the Great Lakes states? What about the Canadian provinces? What about the federal governments? What about the prospect of mischievous, if well meaning, individuals or groups acting on their own?

"We are not even close to developing a governance system to catch up with these emerging technologies," Van Herick said.

And if science does someday allow us to recast the characters in the Great Lakes in a manner never before possible, how do we decide what those characters should be? Do we continue to manage the lakes for maximum sport fishing fun and maybe even modify certain species so they fight harder and have tastier flesh? Do we farm the lakes for energy-producing, genetically modified algae? Or do we try to resuscitate any and all native species in any way possible?

One person long ago figured out where to start.

"A thing is right when it tends to promote the integrity, beauty and stability of the biotic community," famed Wisconsin naturalist Aldo Leopold wrote in 1949, which happened to be the peak of the lamprey invasion. "It is wrong when it tends otherwise."

Perhaps that's as good a place as any to start.

Dan Egan is a reporter at the Milwaukee Journal Sentinel and a two-time Pulitzer Prize finalist. The Death and Life of the Great Lakes was released March 7, 2017.


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