Threats to Our Fisheries

By. Craig B. Nels

            Mark Twain edited a lot of sections out of his novel about Tom Sawyer and Huck Finn.  He felt that there were enough scenes of the two floating down the river in their raft, and there was no need to make the act anything more than it was.  I think for history’s sake though, he should have left one of the parts in, the part about the four foot long fish, that weighs one-hundred pounds, that jumps up onto the raft knocking both of the boys unconscious.  The fish flops around for a second, and then makes its way back into the mighty waters of the Mississippi . Both boys, being unconscious end up drifting downstream for miles before they are washed up on a bank, and proceed to get entangled in another one of their famous adventures. 

            I can see why Twain would edit something like that out, it is just too far fetched, at least up until recently.  At least up until a freak fish farm accident brought this fantasy to life, or should we say nightmare to life. Roaming the mighty Mississippi is now a fish of such proportions that can truly find its way into river-goers boats, by means of air.  Sure, we have all seen anglers pull fish larger than one hundred pounds onto their boat.  Saltwater fishermen do such things all the time.  But the difference is great, the saltwater fish don’t want to come in the boat, they want to stay wet, they want to stay in their own world, under the water.  On the Mississippi though, there is a new inhabitant, the Asian Carp, and it is finding its way out of the world that it belongs in, and into ours. 

Our country has its own carp, it is a very common species across the continent.  They were, however, originally native to Asia . Several hundred years ago they were brought to Europe as a food fish, and in the late 1800s they were introduced to North America . Carp are primarily a warm water species, and do very well in warm, muddy, highly productive (eutrophic) waters.  Adult carp are primarily benthic, feeding on both plant and animal material.  Common carp are native to temperate portions of Europe and Asia . They were first introduced into North America in 1877. At that time they were considered so valuable that the brood stock was fenced and guarded. Since that time countless introductions, both intentional and unintentional, have allowed Cyprinus carpio to become one of the most widely distributed fish species in North America, ranging from central Canada to central Mexico, and from coast to coast. In Texas , common carp are ubiquitous.

Some people see carp as a nuisance in general, no matter what the species is.  Observing carp in shallow water shows how much they can affect an ecosystem.  Rooting around with their suckers and barbells, they churn up the bottom in search of any plant or animal which they desire to eat.  At times, they leave a mucky path in the water showing where they have been.  The species of common carp are generally 12-25 inches in length and weighing 8-10 pounds, although they can grow much larger. Common carp may live in excess of 47 years and weigh over 75 pounds. The all-tackle world record was landed in 1987 from Lac de St. Cassien, France , and weighed in at 75 pounds 11 ounces.  Regardless of the size of the fish, it is not one sought after by many anglers here in the United States .  It is still, though, a valuable game fish in Europe . 

The common carp, which as previously stated, has been in the country for over one hundred years.  It has worked its way into a niche in American waterways.  Any changes that have occurred due to the carp have long since been gotten used to by humans and other creatures alike.  What is happening now though is a different story.  The Asian bighead carp will definitely change ecosystems in ways scientists and citizens alike do not want.  Let’s take a look at what the characteristics of the bighead carp are. 

The bighead carp is a very large, deep bodied fish with a very large head.  The scales are very tiny and the eyes are situated below the midline of the body. The gill rakers are long, comblike and close-set allowing the fish to strain plankton organisms from the water for food. The bighead carp utilizes open water areas, moving about in the euphotic (surface) zones of large lowland rivers, consuming large quantities of bluegreen algae, zooplankton, and aquatic insect larvae and adults. Because of its feeding habits, the species is a direct competitor with the native paddlefish, bigmouth buffalo, and gizzard shad; as well as with all larval and juvenile fishes and native mussels.  While not only being a direct competitor with other fish, it also is an indirect competitor with larger game fish.  When the base of the food chain is affected (the plankton and the baitfish), then the larger game fish will have less to feed on. 

One may wonder though, what were the Asian Bighead carp doing in America in the first place?  Asian or bighead carp are not a valuable game species. The common carp is looked down upon as a food source, but this is  where the Asian carp differs.  Some compare the flesh of an Asian bighead carp to that of tuna, making it a valuable food fish.  With value as a food fish, the carp are then prone to being raised and sold at market.  The farming is where the problem originated.  Two species of Asian carp, the silver and the bighead carps, escaped into the Mississippi River from aquaculture facilities in Arkansas during floods of the early 1990’s. 

While the species has been known by scientists to be possibly dangerous to ecosystems by scientists for a number of years now, it has recently begun to get public attention due to one reason.  The carp can jump up and out of water as high as ten feet.  Common carp can be seen jumping up and out of the water during the summer months (for no known reason), however, they cannot jump much higher than its own body length.  The Asian bighead carp can jump extremely high.  What is also nerve wracking is that the jumps seem to be triggered by the commotion that oncoming boats create.  So we not only have an extremely heavy fish jumping 8-10 feet high, but they are doing it within the vicinity of passing boats.  Now we have humans, fish, vehicles, speed and sheer weight all coming together for a big mess. Jerry Rasmussen, a biologist with the U.S. Fish and Wildlife Service in Rock Island , Ill. stated, "Some of our staff have been hit several times by big carp that landed in research boats.”  There have been a number of other injuries documented.  A woman was also knocked off a jet ski and given a broken nose by a flying carp last summer. 

The movement of the carp is what has proven to be most scary.  Like the zebra mussel, a species that also came from Asia , it is spreading rapidly through our nations clean waters without any major prey species keeping it in check.  The great lakes are the worry of many scientists and anglers alike, for they feel once the fish breaks into that system, it could become the dominant species within a short period of time.  The Mississippi river system comes in close contact with the thousands of lakes in Minnesota as well, where the carp is feared to spread to.  There are also canals connecting the Mississippi to Lake Michigan near Chicago .  In June of 2001, an Asian carp was caught in a small pond within 35 miles of Chicago , which alarmed many.  The Chicago tribune reported,  “A Chicago fisherman's catch from a park district lagoon has alarmed wildlife officials, who fear the spread of a voracious species of carp into Lake Michigan . Sam Pena pulled the 38-pound fish Monday from the pond at McKinley Park , a Southwest Side park at Pershing Road and Damen Avenue .” 

            The fear of the carp getting into the great lakes system has jumpstarted drastic plans to curtail the fish’s movement.  Officials have proposed creating a fish barrier in the Sanitary and Ship Canal and the Cal-Sag Channel, which connect Lake Michigan with the Mississippi River .  The U.S. Army Corps of Engineers has built an electrical barrier in the canal which sends signals that are supposed to repel the fish. Some biologists think it will stop Asian carp, but others say the barrier won't be sufficient. Some want the canal closed, at least temporarily, a move opposed by sanitation department engineers and some boaters. Jerry Rasmussen, a U.S. Fish and Wildlife Service biologist at Rock Island, Ill. Stated, "Why do we need this canal today? It's there because it was easier for Chicago to divert its waste down the canal to the Illinois River , and because some boaters use it. But when you examine the boat traffic that moves on that canal, it isn't very much. I'd liked to see the canal closed for a couple of years, allow it to go stagnant. That would let us treat the carp that are in there now and figure out what to do in the future."  Such a plan may be the best option.  John Rogner, who heads the Fish and Wildlife Service's Chicago office stated, “Tests have shown that Asian carp flee from noise and bubbles, multiple barriers should be placed in the canal, including bubble curtains and noise-makers.”  As one can see, the position for how to stop the problem is still very much up in the air. 

            There is a very clear set of rules, though, for citizens in the fight against the movement of invasive species.  These hold true for all invasive, such as zebra mussels or the goby fish:

1.  Dispose of bait properly: Do not release bait into the water.

2.  Always drain water from your boat, live well, and bilge before leaving                                   any water access.

3.  Never dip your bait bucket into a lake or river if it contains water from                                  another water source.

4.  Never dump live fish from one body of water into another body of                            water.

            The fight against invasive species is a tough one.  An organism that is conditioned to living in one environment, and then deported to a new environment, without the same set of hardships will likely thrive.  That thriving, though, never comes without a cost.  Ecosystems that are in good balance get totally changed.  Sometimes, the effects are devastating.  In the case of the Asian bigheaded carp, the effects are starting to be seen, if not in the data by fisheries biologists, then on the local news talking of a boater who was knocked unconscious by a giant fish while boating.  It is almost too crazy to believe, I wouldn’t have if Mark Twain wrote it.