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Asian Carp in Chicago FAQs

Asian Carp in Chicago FAQs

 

This webpage is intended to provide information on Asian Carp in Chicago. As events unfold, I will attempt to update and refine the information here. Comments, criticisms, and questions are welcome... but your patience will also be appreciated.

 

Philip Willink, Ph.D.

The Field Museum / Fish Division

1400 S. Lake Shore Drive

Chicago, IL

60605

 

pwillink@fieldmuseum.org

 

Created:  2009 / December

 

 

What is an Asian Carp? There is a little bit of confusion around this issue. Generally when people talk about Asian Carp, they mean two closely related species: Bighead Carp (scientific name Hypophthalmichthys nobilis) and Silver Carp (scientific name Hypophthalmichthys molitrix). These are the invasive species that are spreading throughout the Mississippi River, and are now threatening to enter the Great Lakes through the Chicago Canal system. Silver Carp are notorious for jumping. Bighead Carp do not jump (at least as often). Some people are using the term Bigheaded Carp to replace Asian Carp. In each instance, they are talking about the same two species.

            The situation is slightly more complicated in that there are dozens of carp species in the world, and almost all are originally from Asia. None are native to North America, although a few have become established here. Common Carp (Cyprinus carpio) are also carp originally from Asia, but were brought to North America in the 1800s. They have been here so long that many people think they are native. Goldfish (Carassius auratus) are also a type of carp from Asia, and they can be surprising abundant in urban environments. Grass Carp (Ctenopharyngodon idella) is another type of carp from Asia that is routinely stocked in ponds and rivers to control excessive plant growth. Black Carp (Mylopharyngodon piceus) is sometimes mistakenly moved around with the similar looking Grass Carp. So in one sense, there are actually six species of invasive Asian Carps. But this is not what most people mean when they say Asian Carp.

            As an aside, all carps are related and in the family Cyprinidae. Many of our local native minnows are also in the family Cyprinidae, hence are distant relatives to the Asian Carp.
 

 

Will the Electric Barrier prevent the spread of Asian Carp into the Great Lakes?  NO. You would be hard-pressed to find a fish biologist that believes the electric barrier will stop the spread of Asian Carp from the Mississippi basin to Lake Michigan. We have been using electricity to survey fishes since the 1930s. Biologists have a lot of experience using this method, and it is one of the best for collecting fishes. However, when you are in the field you always notice a few individuals getting away. Whether it is something about those particular fish, or water chemistry, or something in the habitat, or some other factor, electricity is not 100% effective. It may very well be up to 99% effective, but that is not good enough to stop the spread of invasive species. We need something that is 100% effective. The electric barrier is simply not good enough.
            There is also the issue that a section of the Des Plaines River floods upstream of the Electric Barrier. Since Asian Carp have unrestricted access to the Des Plaines River, they can swim up it then bypass the Electric Barrier all together. It is my understanding that there are plans to put in a fence along this flood zone to prevent the passage of fishes. Whether this will be done in time, or if it is even too late, is something we will find out in the future.
 

 

If the Electric Barrier is not going to work, then how can we stop the spread of Asian Carp into the Great Lakes? Our options are limited. The basic biological issue is this: fishes have been swimming in this planet’s rivers, lakes, and oceans for millions of years. They are extremely good at it! If they were not, they would have gone extinct long ago. The only factors that reliably stop fishes from swimming from one place to another are 1) dry land and 2) waterfalls. (Some fish species can walk over land, and a few can climb waterfalls, but fortunately Asian Carp cannot do either.)

            In my opinion, the only viable method of stopping the spread of Asian Carp through the Chicago Canal system is to close the locks and dam the canal (i.e., the width of the dam is being considered impassable ‘dry land’). You could conceivably allow some of the lock-and-dam complexes to spill over, forming waterfalls. If these waterfalls are high enough, then the Asian Carp could not jump over them. The Lockport, Brandon, and Dresden lock-and-dam complexes may be high enough.

            The problem with closing the Chicago Canal system is that boats and barges will no longer be able to use it. As long as boats and barges can move through the Chicago Canal system, so can fishes. We need to accept this fact.

            Complete closure of the Chicago Canal system would allow waste water from treatment plants to flow back into Lake Michigan. If you allow some of the lock-and-dam complexes to spill over to form waterfalls, then waste water would continue to flow towards the Mississippi, as it has done for the last century.

            I have not seen any other realistic options.

            Experience has shown that using rotenone to kill fishes is an extremely short-term solution. The moment the rotenone dissipates, fishes from nearby areas begin to re-colonize the kill zone.

            The bottom line is that we need to choose between keeping the canals open to allow boats and barges to move between the Mississippi and Great Lakes, or close the canals and stop the spread of invasive Asian Carp. This is a difficult decision. Many people’s livelihoods are dependent upon the movement of goods through the Chicago Canal system, and this is one of the factors that made Chicago a great, international city. But many people are also dependent upon the Great Lakes fisheries. And one has to consider the unique and irreplaceable natural heritage of the Great Lakes.

 

What is the nearest Asian Carp record for Lake Michigan?  In 2004 a Silver Carp was found roughly two miles downstream from the Electric Barrier. This was reported in the papers at the time, and the record has been published online and in books. We (or at least some of us) have known for years that occasional Asian Carp are swimming up to the Electric Barrier. The main body of the Asian Carp invasion still appears to be further downstream, somewhere between Channahon (where Interstate 55 crosses the Des Plaines River) and Joliet. This is a fairly typical pattern for a species expanding its range. You first see a few stray individuals that tend to wander from the rest of the group. Over time you see more and more of them until they become established permanent residents.
            The Bighead Carp caught during the 2009 December fish kill was actually further downstream from the Electric Barrier (i.e., further from Lake Michigan) than the 2004 Silver Carp record. Its capture was basically a confirmation of what some of us had known for years.
            Bighead Carp have also been caught in McKinley Park lagoon (in 2003 and 2004), Columbus Park lagoon (in 2006 and 2009), and Garfield Park lagoon (2010), all in Chicago and upstream of the Electric Barrier. However, to the best of my knowledge, these lagoons are isolated from all other water sources. In other words, there is no way these carp could have swum there. Instead, someone put them there, either accidentally or intentionally. We do not know who or why.

            Bighead Carp were also been found in Lincoln Park, South Pond in 2008. Once again, it is believed that someone put them there, either accidentally or intentionally. This situation is a little different because this pond was directly connected to Lake Michigan via an overflow drain. There was a screen in the drain, and the amount of water varied, but we do not know if this was enough to stop fishes from moving through. (The pond was poisoned and drained in late 2008.) To date, this is the closest record to Lake Michigan.

           A Bighead Carp was found in Lake Calumet in June 2010. Lake Calumet has unrestricted access to Lake Michigan, but is several river miles away. It is unclear if the fish swam there through the Chicago Canal system or was put there by somebody. Extensive sampling in the nearby Calumet River and Calumet Sag Channel did not produce any Asian Carp. And for years people have been putting Asian Carp in Chicago park ponds. So both options are possible.  

 

Have Asian Carp been found in the Great Lakes? YES, but there is no solid proof they are in Lake Michigan. Bighead Carp have been found in Lake Erie in 1995, 2000, 2002, and 2003. To the best of my knowledge, they have not established a breeding population there. We do not know how they were introduced, but presumably someone dumped them in the lake. Why and whether it was accidental or intentional is unknown.
 

How many Asian Carp have to pass the Electric Barrier before they are established in Lake Michigan? At least 2, but probably a lot more. When Asian Carp spawn, a female releases eggs into the water, and then a nearby male releases sperm into the water. Some of the eggs will fertilize and become baby carp. This is why you need at least two fish: one female and one male.

The tricky part is the 2 fish need to be near each other at the right time and in the right place. Usually the right time and place is in a river in the Spring. So if we were to take 2 Asian Carp and dump them in the middle of Lake Michigan in late Summer, the likelihood that these 2 fish would be next to each other the following Spring is almost Zero.

However, if we were to take 100 or several hundred Asian Carp and confine them between two dams in a river with suitable habitat, then we would have a very good chance of having lots of Asian Carp babies. A single female Bighead Carp can have 11,000 to 1.8 million eggs, and single female Silver Carp can have 57,000 to 4.3 million eggs. The vast majority of the eggs / young are eaten or die, but you can see how it is possible to get a lot of Asian Carp very quickly under the right circumstances.

            One relevant example is the establishment of a Silver Carp population in the Gobind Sagar Reservoir, India after the accidental escape of approximately 47 individuals.

 

If (when) the Asian Carp pass the Electric Barrier, is there anything we can do to stop them from entering Lake Michigan? Not much. Once past the Electric Barrier, there are at least 5 access points into Lake Michigan. Three of these have structures that control the flow of water (1 – O’Brien Lock-and-Dam in the Calumet River, south side of Chicago, 2 – Chicago Lock at the mouth of the Chicago River, downtown Chicago, and 3 – Wilmette Sluice Gate at the north end of the North Shore Channel, Wilmette Harbor) and can be closed. The other two (1 – Indiana Harbor via the Grand Calumet River, and 2 – Burns Harbor via the Little Calumet River) do not have lock-and-dam complexes, so they cannot be closed. (As far as I am aware. If anyone knows differently, then send me a message.) The last two are relatively small, shallow, and marshy in places, but fish can still pass through, especially when water levels are high. Asian Carp may have to swim around for a little while, but eventually they will find their way into Lake Michigan.

            You may have heard of government officials requesting the closure of the O’Brien Lock. Unfortunately this will accomplish little. The Asian Carp will either swim through another lock that is open or through a channel that does not have a lock.

            In theory you could use nets or poison to block the channels, but in reality this is almost impossible. Nets tear and it is difficult to set them in a manner such that fishes could not sneak around them. Any passing boat would rip a net to shreds. Poison only works for a few days at most, and only affects a small area.

 

When will Asian Carp enter Lake Michigan? Or if you think they are already in Lake Michigan, when will they enter in significant numbers? Anywhere from one month from now to several years from now. To some of us that have been tracking Asian Carp, this is the biggest mystery. Once these fish entered the Illinois River, they rapidly crossed the state of Illinois. If they had continued swimming upstream at that same speed, they should have been in Lake Michigan a couple years ago. (This is assuming the Electric Barrier would hinder their movement, but not stop them.)

            However, somewhere between Starved Rock State Park and the junction of the Des Plaines and Kankakee rivers, the Asian Carp slowed down. Let me emphasize that they did NOT stop. They are still moving towards Lake Michigan, just not as quickly as they once were. And we do not know why.

            It is possible the lock-and-dam complexes are slowing them down, but they have already passed numerous lock-and-dam complexes elsewhere. Perhaps there is not enough plankton, their food?  But Gizzard Shad and other plankton eating fishes are abundant in the area. I once thought pollution coming out of Chicago was slowing them down, but the Asian Carp appear to be more numerous in the Des Plaines River (which receives Chicago’s pollution) than in the nearby Kankakee River (which is relatively cleaner). Plus, Asian Carp have not had trouble with pollution elsewhere. Lack of oxygen dissolved in the water has been suggested, but that does not seem to explain this either. All we know is that some environmental variable(s) is slowing them down, but not stopping their movement towards Lake Michigan.

            The good news is we still have time to act. The bad news is the Asian Carp could overcome this hindrance at any time and rapidly start swimming towards Lake Michigan. We do not know enough about these fishes to make an accurate prediction.

 

What impact will Asian Carp have on the Great Lakes? The honest answer is: We do not know. We will only know for sure years after it happens. And by then it is too late. But we can make an educated guess based on what we do know about their biology.

            The following is a quote from Duane Chapman (USGS in Missouri): “In Asia they [Asian Carp] are rarely captured from flowing water except during spawning events. They don't live in the rivers, they live in associated floodplain lakes. In the USA, they don't have as many floodplain options, so they exist mostly on channel margins or slow-moving tributaries or behind wingdikes. [Wingdikes are rows of rubble or other debris that angle out into a river to channel the flow towards the center of the river. The water downstream or behind a wingdike is still and calm, like behind a breakwater.]”

“In Lake Balaton in Europe, in reservoirs in Pakistan, and many other places around the world where carp have access to rivers and lakes or reservoirs, the adult fish primarily live in the open water of the lake (where it is extremely difficult to catch them, because the fish are so net and boat shy that it is difficult to encircle them, and they swim under or jump over nets). In Lake Balaton, 1/5 the size of Lake Erie, and similar in temperature and water chemistry to Lake Erie after it was cleaned up but before zebra mussels invaded, the silver carp are HUGE and very happy out in the middle of the lake. Average size in my colleague's last week sampling trip was 33 pounds, the average fish bigger than any silver carp I have seen in the USA.”

            What is fascinating and unfortunate about this is Asian Carp in their native range primarily live in large rivers or lakes alongside rivers that seasonally flood. They prefer still to slow-moving water. But if they are unable to find their native habitat, they can adapt to their current conditions and find similar habitats, such as the sides of river channels out of the main current, reservoirs, or large lakes. They are very good at finding places to live. They have done so in the Mississippi River, and will presumably do so in the Great Lakes.

            We would not expect to find them in large numbers in small streams or deep in the Great Lakes.

            Asian Carp eat plankton, small plants and animals floating in the water. They therefore compete directly with anything else that eats plankton. This includes adult fishes, like Alewife. But more significantly, it includes baby fishes, like juvenile Yellow Perch and just about every other fish species in the Great Lakes. Asian Carp appear to be superior competitors, so we expect declines in the abundances of many fishes. You would also expect that there will be more Asian Carp where there is more food (i.e., higher plankton concentrations).

            Juvenile Asian Carp will be eaten by large predaceous fishes, like salmon, pike, bass, etc. But the Asian Carp grow quickly and soon reach a size too large for other fishes to feed upon them. The only significant predator of adult Asian Carp is people.

            There has been a lot of talk about Asian Carp needing 60 miles of free flowing, undammed river water to reproduce. This has to do with their spawning behavior and subsequent development of fertilized eggs / embryos. What happens is Asian Carp in the spring when water levels start to rise congregate in a particular area in a river. The females release eggs into the water, the males release sperm into the water, and you get baby Asian Carp. Actually, you get tiny fertilized eggs that drift downstream with the current. The current is thought to keep the fertilized eggs suspended in the water, where they are ‘safe’. If they drop to the bottom of the river, some think that the fertilized eggs get buried by sediment or eaten. That is why you need a river 60 miles long for Asian Carp to successfully reproduce. The fertilized eggs need to be suspended in the water column until they have a chance to hatch.

            In my opinion, I would downplay this requirement. I suspect the fertilized eggs are more resilient than we realize. And there are instances where other species of fishes with similar riverine spawning requirements are known to spawn along wave-swept lakeshores. What will probably happen is that there will be lots of Asian Carp spawning in all kinds of different places, and those that are successful will multiply rapidly. Keep river size in mind, but do not get overly fixated on it.

 

What is eDNA or Environmental DNA? The procedure is basically taking a sample of water, isolating DNA from it (which presumably was shed by fishes swimming nearby), and then matching the DNA with known DNA sequences of the species of interest. In these days of CSI and other scientific breakthroughs, the technique has great promise.

            The problem is the Asian Carp eDNA method has not been thoroughly validated, so it is difficult to interpret the results. A primary point of contention is that the method indicates that Silver Carp are present in numerous, widespread localities, but nobody can find an actual fish. And keep in mind that Silver Carp are relatively large fish that swim near the surface and have a tendency to jump in the air when boats pass by. So they are not sneaky fish.
            Also the molecular methods used in the eDNA process can have problems with contamination when dealing with trace amounts of DNA. It is very difficult to ever rule out contamination causing problems, especially when such a small percentage of samples are showing indications of DNA.
            Hopefully in time we will have a better idea of what is going on here. At the moment, it is difficult to know what these data mean.
            As an aside, people's opinions about eDNA tend to be tightly correlated with their political views. So it is very difficult to get an objective evaluation of the process.
 

If Asian Carp invade the Great Lakes, where exactly would we expect to find them? What impact will Asian Carp have on the Great Lakes’ fisheries? There is continued interest in what impact these fish could possibly have on the $7 billion commercial and recreational Great Lakes’ fisheries, and this is a critical component in arguments being made as to whether to close the Chicago canals or not. On one side you hear people say that the Asian Carp will completely take over the entire Great Lakes and destroy all the fisheries. On the other side you hear people say that Asian Carp could not even survive in the Great Lakes, and hence will be no problem at all if they get in. Biologists are currently arguing about this, and it is surprising that many of us are coming to similar conclusions. This is complete speculation because it has not happened yet. But we can make some educated guesses. As is usually the case, the most likely scenario predicted by many biologists is complicated and somewhere in between the two extremes presented above.

            When most biologists are trying to figure out where Asian Carp may live in the Great Lakes, they look at five factors: habitat, temperature, predation, competition, and food.

            In regards to habitat, Asian Carp are known to live in large rivers and lakes. They are not usually found in small streams, so large rivers and lakes are our starting point.

            In regards to temperature, the native range of Asian Carp extends into southern Siberia. So they will have no trouble surviving the cold winters of the Great Lakes region. But there is a difference between surviving and prospering. Cold temperatures may not kill Asian Carp, but they may not be able to maintain their competitive edge over other fish species at cold temperatures. The feeling among biologists is Asian Carp will mostly be in the relatively warmer waters near the surface. They probably will not be abundant in the cold, dark depths 100, 200+ feet below the surface. However, if food is abundant in cold water, Asian Carp will go there to feed.

Young Asian Carp will be eaten by predatory fishes (like Salmon, Pike, Musky, Bass, etc.), but adults are too big to be eaten by other fishes, so predation is unlikely to limit the spread of Asian Carp.

Predicting the outcome of competition among species before it happens is extremely difficult. But we have learned lessons in the Mississippi and elsewhere in the world. In short, we have reason to believe that Asian Carp have the ability to outcompete many of our native species, such as Gizzard Shad, Yellow Perch, Walleye, etc. However, in the Great Lakes, Alewives may be an exception to this. They are very good at feeding on plankton, and may be better at it than Asian Carp. Another source of serious competition will be Zebra Mussels and Quagga Mussels. They are also extremely good at feeding on plankton, and have had a tremendous impact on the Great Lakes. They may actually limit where Asian Carp can survive. But there is still plenty of plankton in parts of the Great Lakes, and that leads us to our final factor.

            Asian Carp are expected to be most abundant where there is lots of plankton, their food. Some scientists are calculating how much plankton is here and there in the Great Lakes, and how much Asian Carp need to eat, and so forth. I will not go into the details here. There is another way that leads to generally the same conclusions. We can look at the distribution of OTHER fishes that eat plankton and see where they live in the Great Lakes. If there is enough food for these other species, then there could be enough food for Asian Carp. Fortunately we have two great candidates; the Alewife Alosa pseudoharengus and the Gizzard Shad Dorosoma cepedianum.

            Michigan has done an excellent job posting maps of fish distributions at:

http://www.michigan.gov/dnr/0,1607,7-153-10364-30538--,00.html

Please keep in mind that the data are only for the state of Michigan. Other areas, like Canada, Wisconsin, Ohio, etc. are not included, so those portions of the map are left blank. But what you see at this website is very insightful. (My apologies for not just posting the maps on this website, but I am not sure if I have permission to do so or not.)

            If you go to the website and click on the Alewife map, you will see that they live throughout lakes Michigan, Huron, and Erie. (Just to clarify, Erie is mostly blank because it is mostly within Ohio and Canada, and the map is just of Michigan. Alewives actually live throughout Lake Erie.) But they do not live in Lake Superior. This is because there is very little plankton there for them to eat. There are a few records, but those are really just stray individuals that wandered up there.

            It is possible that Alewives are better at finding plankton than Asian Carp are. So we should look at another example. In the Mississippi, Gizzard Shad and Asian Carp are often in the same areas, and we know that Asian Carp can outcompete Gizzard Shad. If you look at the Gizzard Shad map on the website, you will see that they are found in Lake Erie, Lake St. Clair, Saginaw Bay, the shorelines of southern Lake Michigan, the Grand River, Kalamazoo River, and Saginaw River. These are many of the areas that are thought to have higher plankton concentrations. And keep in mind that we know that Bighead Carp can live in western Lake Erie because several have already been caught there.

            After combining all I have said above, the following satellite image actually does a good job at presenting where many of us think Asian Carp will live in the Great Lakes. (And it is a nice picture.)

 

 

I am not exactly sure what the green areas within the Great Lakes are, but it is not depth. Instead it may be algal blooms or nutrients or runoff or something like that. Regardless, it these green areas that come close to where some of us think Asian Carp will live. Most will be in places like western Lake Erie, Lake St. Clair, Saginaw Bay, Green Bay, the southern shoreline of Lake Michigan, the southern shoreline of Lake Huron, and a few other places. You can even see plumes from some of the larger river mouths emptying into Lake Michigan. Large rivers without dams and abundant nutrient runoff from agricultural fields are also expected to have Asian Carp.

            I have yet to talk with a biologist that believes there will be large numbers of Asian Carp in Lake Superior. It is cold and has very little food for Asian Carp. They are also unlikely to be abundant in the centers of Lake Michigan, Lake Huron, or Lake Ontario. Occasional individuals will swim just about anywhere, but basically Asian Carp will be absent from most of the Great Lakes. The downside is Asian Carp are predicted to be most common in the parts of the Great Lakes that are most heavily utilized by boaters and tourists, so there could be a lot of human-carp interactions.

            Once again, this is all speculation. But it is an educated guess based on what we know about the biology of Asian Carp and what we know about the ecology of the Great Lakes. It is always possible that they may do better than we anticipate. Or they may do worse. But it is important to point out that the Great Lakes is a massive ecosystem with many different areas, and hence it makes sense that we would see Asian Carp abundant in some places and absent in others.

            If you accept this hypothetical scenario, or even one similar to it, then it is difficult to argue for the complete collapse of the Great Lakes’ fisheries. The impact of Asian Carp on Lake Superior will be little to none. Those fisheries will be fine. Most of the Great Lakes will be free of carp. On the other hand, the western basin of Lake Erie with its world class Walleye and Yellow Perch fishery could be hard hit. It could be in trouble. Water-skiing on Lake St. Clair with jumping fish could be exciting. The Lake Michigan Salmon fishery will be negatively impacted, but the impact could be moderate to so slight as to be unnoticeable. It is difficult to predict because Salmon tend to be in deeper, colder waters of the lake, while Asian Carp are predicted to be in the shallower, nearshore waters. The overlap between the two groups would be minimal.

            All of this is open to argument. But the take-home message is that some fisheries will be impacted while others will not. The situation is much more complex than is usually presented. The best solution is to not let Asian Carp into the Great Lakes so that none of this happens.

            And NO, I will not put a dollar amount on how much damage Asian Carp could do in the Great Lakes. That is missing the point altogether. (Posted 2010 / March)

 

Is there an online video game about Asian Carp in Chicago? The Field Museum Education Department is pleased to announce the launch of Invasion!, an online game about the Asian Carp.

            Start off as a pesky carp, out-competing other river species for food and knocking humans out of boats! Then switch roles and become the Carp Czar of Chicago and keep this invasive species from reaching Lake Michigan! Be careful though…you have limited money and political capital to spend, and both random events and the carp can undermine your good intentions!

You can play the game whenever you like by clicking on this link:

http://www.etc.cmu.edu/projects/bridges/invasion

A special thanks to Dr. Phil Willink for serving as the content expert and the Bridges Team at Carnegie Mellon’s Entertainment Technology Center for designing and developing the game.

 
 
 
 

The following FAQs are more general in nature, pertaining to Asian Carp and the Great Lakes, but not necessarily the situation in Chicago:

 

Why are Asian Carp not a problem in Asia, their native home? What natural factors prevent them from becoming super-abundant? There are a variety of factors at work here. In much of modern-day Asia, Asian Carp have been a popular food fish for a long time, so they are harvested commercially. Overfishing is the real problem. Asian Carp numbers are also hurt by dams and pollution destroying their natural habitats.

            Prior to people having such an impact on the Asian environment, the story was different. We do not know how abundant they were at this time, but there could have been a lot of Asian Carp. There were also other species of fishes that fed upon plankton, hence competed with Asian Carp for food. There was also a limited amount of habitat suitable for spawning and feeding.

            In addition to competitors and habitat, there were predators that presumably ate Asian Carp, particularly the young. Some examples are two species of freshwater dolphin, a 20-foot paddlefish (the Chinese paddlefish ate fish, whereas the much smaller North American paddlefish feeds on plankton), several species of snakeheads (another famous invasive species that has been in the news), and others.

            So a combination of competition, predation, and habitat availability presumably kept Asian Carp numbers in check. And we can expect the same thing in the Mississippi, and possibly the Great Lakes. Oftentimes with invasive species their numbers increase dramatically at first, then drop down to a semi-equilibrium point. Where this semi-equilibrium point will be with Asian Carp, we do not know at this time. It could take years or decades before we find out. Many of our native species will suffer in the short- and long-term.

            (Duane Chapman (USGS in Missouri) helped provide some of the ideas in this FAQ.)

 

Can you eat Asian Carp? YES. Asian Carp are a very popular food fish in many places around the world. They are not so popular in the United States for a couple of reasons. First, people react negatively to the name Carp and assume the fish tastes bad. This is not a particularly fair judgment, and is more a matter of personal taste. Second, they do tend to be bony, and have some bones that are more difficult to remove. But with a little extra effort, these can be dealt with easily enough. The bottom line is that there really is no reason not to eat them.

 

If you are still interested in eating Asian Carp, check out these videos provide by Duane Chapman (USGS in Missouri):

Flying Fish, Great Dish (Part 1: Introduction & Removing Filets)

http://www.youtube.com/watch?v=T1NVUV8yhmU

 

Flying Fish, Great Dish (Part 2: Making "Flying Carp Wings")

http://www.youtube.com/watch?v=CB-fmA07gZ8

 

Flying Fish, Great Dish (Part 3: Deboning Filets & Closing Credits)

http://www.youtube.com/watch?v=RhGkjwxm_0o

 

Can commercial fishing be used as a method to control or eliminate Asian Carp? YES, but there is the potential for some interesting consequences. This idea has been around for years, but only recently is it really being taken seriously by most people. Some areas have even renamed Asian Carp, marketing them instead as ‘Silverfin’ in order to increase their appeal. And Asian Carp recipes are popping up all over the place on the internet.

            First, do we even have the ability to control a species by fishing for it? The answer is a resounding YES. As a matter of fact, overfishing is the primary factor in the extinction of two species and one subspecies of fish in the Great Lakes! And I will not even go into what we are doing to the world’s oceans. We are more than capable of fishing a species into oblivion.

            And some type of regulated fishing in the upper Illinois River is about the only way the Electric Barriers are going to succeed. I say this because just about everyone thinks that an occasional fish will sneak by the barriers. But if only a few fish even reach the barriers, then it is far less likely than any (or at least large numbers) will get by. So if we can keep Asian Carp numbers down in the upper Illinois River, then fewer fish will approach the barriers, and it is more likely the barriers will be successful in repelling those few fish. Basically it is a numbers game, and we want to keep the numbers as low as possible.

            Now here is the catch. If we are trying to set up a fishery whose intent is to eliminate Asian Carp, then we are basically setting up a business whose purpose is to go out-of-business. That is not a sound long-term business model. It would be more attractive with government subsidies, but then we (taxpayers) are paying for it. There is certainly a short-term financial appeal because there are a lot of Asian Carp, but there are problems over the long-term.

            A more interesting scenario is what happens if Asian Carp become a popular fishery. People are making money off it, and want to continue making money. Or we learn to like eating Asian Carp. Then instead of trying to eliminate Asian Carp, we may want to keep them and start managing them like all our other fishes.

            If Asian Carp become popular enough, then people may start moving them around to new rivers and lakes so as to increase the fishery. Then the fishery has actually resulted in increasing the range of Asian Carp. And finally, if Asian Carp get into the Great Lakes and are popular, then instead of destroying the entire Great Lakes’ fishery, they would instead become an integral part of the Great Lakes’ fishery!

            This may sound crazy, but go ahead and read fishery reports from the 1800s, through the 1900s, and into the 21st Century. You will be amazed at how people’s opinions change over time. Sometimes it takes 10 years, 20 years, 50 years, but they do.

            Just to clarify, I do NOT think that we should introduce Asian Carp into the Great Lakes so we can start a commercial fishery for them. But I would be remiss if I did not mention the possibility. Just something to think about. Commercial fishing of Asian Carp is a powerful tool in battling this invasive species, and one we should use, but we need to be smart and think through the consequences. (Posted 2010 / March)

 

As is often reported, did Asian Carp first escape into the Mississippi River during the massive 1993 floods? NO. In some respects, the truth is actually scarier. Asian Carp were first brought into the United States in the early 1970s. It did not take long before they escaped. The first Silver Carp caught in the Mississippi basin was in 1974 or 1975. The first Bighead Carp was caught in 1981. It did not take a natural disaster to release them into the wild. They are quite adept at escaping on their own.

 

As is often reported, do Asian Carp make up 90% of the fishes in the Mississippi River or Illinois River? There are certainly a lot of Asian Carp in these rivers. Nobody doubts that. And there are more now than there were 40 years ago, when there were no Asian Carp. But there appears to be some confusion about exactly how many there are today. For example, see the following quote by Duane Chapman (USGS in Missouri):

“These quotes on biomass in the Mississippi River or Illinois River or Missouri River of Asian Carp being 90% of the total (or, I saw today, now 95%!) are not based on any study or any fact. I fear the number results from a talk I gave where I was talking about how much of my catch is Asian Carp, using methods similar to those used by commercial fishers to catch Asian Carp and buffalos [In this instance, buffalos are type of native fish related to redhorses, suckers, and carpsuckers]. About 2/3 of the fish I catch when targeting Asian Carp are Asian Carp, and I don't usually weigh the native fish, but since they are so much smaller than the Asian Carp, the poundage of the catch is probably between 80 and 90% Asian Carp by weight.  I was referring to bycatch when targeting Asian Carp, not the biomass of fish in the river.  I don't know this is where that came from, but I fear it is so. “

            Okay, what Duane is saying here is that when he goes out to intentionally catch Asian Carp, 90% (by weight) of what he catches are Asian Carp. But he is not trying to catch ALL the fishes in the river, so he does not know how Asian Carp numbers compare to all the other fish species.

            Admittedly, this is a little confusing and we are nitpicking about facts. For the time being, let us just say there are a lot of Asian Carp. There is no dispute about this. Once I find data from a better study, I will post it on this website.

 

Does drinking water in Chicago suburbs have anything to do with Asian Carp? Ahh... this is where things get really complicated. I suspect that the long-term solution to the flow of the Chicago River, invasive species, etc. will eventually come down to readily available, affordable drinking water. I say this because a reporter in December 2009 went on the streets of Chicago and randomly interviewed 25 people about Asian Carp. (I wish I could find this reference, but seem to have misplaced it.) Of the 25 people, 23 had no idea what the reporter was talking about and did not really care. The remaining two were very much anti-Asian Carp. In other words, the majority of people do not find Asian Carp too interesting or important, while a few people get very emotional about this issue. If you were to go out and recreate these interviews today, but asked about drinking water, then everybody would have an opinion because everybody cares about drinking water. And preferably this water would be clean and cheap. Ironically, few people actually know where their drinking water comes from.

            Now back to the Chicago River. The river was reversed to dilute sewage and facilitate shipping between the Great Lakes and Mississippi. This resulted in numerous lawsuits over the years. The most relevant to this discussion is a 1967 Supreme Court ruling that allows Chicago to divert 2.1 billion gallons a day from Lake Michigan into the Mississippi watershed. This includes drinking water for 7 million people, water to dilute sewage, water to fill the Chicago canals so boats can move through, and rainfall on parts of the Chicago Region. The ruling also allows Chicago to pump water outside the Great Lakes basin as long as it remains under the 2.1 billion gallons a day cap. For a more thorough description of the Chicago Diversion, I recommend The Great Lakes Water Wars by Peter Annin.

            If the Chicago River is re-reversed by permanently separating it from the Mississippi basin and allowing it to flow back into Lake Michigan, then in theory this frees up a huge volume of water that could be used as drinking water to sustain communities in Northeastern Illinois (and possibly Wisconsin and Indiana as well). The primary benefit is reducing stress on underground aquifers in the region, for lack of well water / groundwater could be a serious problem in the future.

            I should caution that this is easier said than done, and I am greatly oversimplifying this issue! For example, there will have to be significant upgrades in how we treat sewage. Many water pipes will have to be refitted. And there are a host of other hydrological issues. Not to mention politics! But in my opinion, this seems to be the direction in which the Chicago Region is headed. It will take years to resolve this, but it will have to happen some day. (Posted 2010 / February / 3)

 

Where can I learn more about various Great Lakes issues?

Protecting the Great Lakes from Diversion, Pollution, Climate Change, Catastrophes, and Invasive Species was a symposium sponsored by the Seventh Circuit Bar Association Foundation and held at the Field Museum of Natural History on February 24, 2012. It was a day filled with presentations explaining the threats to the lakes, the programs designed to enhance sustainability, and the complexities of the legal regimes. All the presentations were recorded and can be viewed at    http://www.7thcircuitbar.org/



Semi-Random Thoughts and Opinions

 

"It is time to seriously consider re-reversing the Chicago River. The city of Chicago stunned the world in the 19th Century by reversing the flow of the Chicago River, an act that saved thousands of lives from water-borne diseases and facilitated the transport of goods which stimulated the region's economy and helped propel Chicago onto the international stage. Now, in the 21st Century, Chicago has another opportunity to be a world leader by protecting the Great Lakes, one of this planet's largest freshwater ecosystems. Chicago's history is intricately linked with water, as is its future." (2009 / December / 22)

 

"The Asian Carp and the Chicago Canal System have unwittingly created an opportunity for one of the most important decisions influencing the future of the Great Lakes. This has less to do with the impact the Asian Carp may or may not have on the Great Lakes' ecosystems, and more to do with society's values. Will the environment play a role in decision making? Or are the Great Lakes simply a resource to be profited from? Future ramifications will be applicable to other invasive species, pollution, parks, drinking water, trans-oceanic shipping, etc. What does society see as important? What does society truly value?" (2009 / December / 22)

 

"The Asian Carp and the Chicago Canal System are on the brink of becoming a text-book example on the handling of invasive species. Whether it will be judged a landmark success or a complete failure remains to be seen. It is very close, but at the moment it looks like the Asian Carp have a slight advantage. The situation can change rapidly." (2009 / December / 22)

 

 

Suggested Reading

 

Kolar, C.S., D.C. Chapman, W.R. Courtenay Jr., C.M. Housel, J.D. Williams, and D.P. Jennings. 2007. Bigheaded carps: a biological synopsis and environmental risk assessment. American Fisheries Society, Special Publication 33, Bethesda, Maryland. - Most comprehensive treatment of what is known about the biology of Asian (aka Bigheaded) Carp. However, what we know is always changing, so supplement this text with recent publications.

 

Willink, P.W. 2009. Book review: Bigheaded carps: a biological synopsis and environmental risk assessment. Copeia 2009:419-421. - For a PDF of this publication, please go to the bottom of this webpage and click on 'Willink Asian Carp book review June 2009.pdf'.

 

DeGrandchamp, K.L., J.E. Garvey, and R.E. Colombo. 2008. Movement and habitat selection by invasive Asian Carps in a large river. Transactions of the American Fisheries Society 137:45-56.

 

DeGrandchamp, K.L., J.E. Garvey, and L.A. Csoboth. 2007. Linking adult reproduction and larval density of invasive carp in a large river. Transactions of the American Fisheries Society 136:1327-1334.
 
Bowman, D. 2009. We've wasted millions on electric barrier boondoggle. Chicago Sun-Times, December 1, 2009. - This article lists the occurrences of Asian Carp in Chicago park lagoons.

 

Haskell, D.C. 1940. An electrical method of collecting fish. Transactions of the American Fisheries Society 69:210-215.

 

Funk, J.L. 1949. Wider application of the electrical method of collecting fish. Transactions of the American Fisheries Society 77:49-60.
 
Willink, P.W. and F.M. Veraldi. 2009. The fishes of Will County, Illinois. Fieldiana: Zoology: New Series, No. 115:1-61. - This publication is an overview of the 112 fish species known from the rivers, creeks, and lakes in the county containing the Electric Barrier. Asian Carp are briefly mentioned, but the publication is really about ALL the fishes and aquatic habitats in the area.
 

Annin, P. 2006. The Great Lakes water wars. Island Press. An excellent overview of Great Lakes water issues and politics. Not actually about Asian Carp.

 
 

Philip Willink’s homepage

http://sites.google.com/a/fieldmuseum.org/pwillink

 
If you are are interested in learning more about Chicago Region fishes (including downloading a free field guide to Chicago Lakefront Fishes), then please go to:
 
 
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Philip Willink,
Dec 11, 2009, 10:22 AM
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