The Mississippi is one of the greatest rivers in the world. Drainage of this river and its tributaries embraces nearly one-third of the land surface of the United States. It is more than 4,000 miles in length from the headwaters of the Missouri River tributary to its confluence with the Gulf of Mexico.
The river was discovered by DeSoto in 1541. Marquette and Joliet were the second white men to see the Mississippi when they reached the mouth of the Wisconsin River in 1673. These voyagers were warned by the Indians before going onto the river that it was inhabited by demons and giant fish that would most certainly destroy them.
Mark Twain believed Indian traditions were based on the presence of giant sturgeon, paddlefish and catfish. In "Life on the Mississippi," he wrote of having seen monstrous-sized catfish "six feet long, weighing 250 pounds." Even today, traditions and myths survive among river people of giant fishes and other river creatures of fabulous size.
When white men first visited Iowa, the Mississippi was a major source of food for the native Indians. The great burial mounds along the Mississippi River contain evidence that prehistoric tribes depended greatly on this "Father of Waters" for stable food supplies of both freshwater mussels and fishes.
The Mississippi River borders Iowa for more than 300 miles, entering the state between precipitous bluffs that rise four to six hundred feet above the river level. Bluffs diminish in size and spectacular appearance from Bellevue southward. The river meanders east and west through numerous side channels, chutes, and sloughs across its two- to six-mile wide valley. From north to south along our entire border, the river becomes systematically wider -- but shallower. The river bed is primarily sand and mud, with few bedrock outcroppings, the most notable of which are the Rock Island Rapids between LeClaire and Davenport and the Keokuk Rapids above the mouth of the Des Moines River.
Waters of the Mississippi become muddy during flood conditions. Much of the time, however, it is quite clear, this being particularly true in late summer, autumn and winter. Our part of the river flows about two miles per hour during normal water stages, although current speeds of up to five miles per hour are common during high water periods.
The Mississippi River in its original appearance consisted of a seemingly unending series of pools separated by shoals, bars and rapids, with a channel or series of channels between -- much like our larger interior streams today. These channels were obstructed by rocks and snags which, during low water levels, separated into many side channels of narrow width and little depth until the stream took on a "braided" appearance.
Initial engineering on the Mississippi River occurred in 1824 when Congress authorized improvement for navigation by the removal of snags and other channel obstructions. As early as 1836, improvements were carried on by removal of snags and steamboat wrecks from the rapids at Keokuk and Rock Island. Shortly after this date, a canal and locks were constructed in the river at Keokuk. In 1905, an act of Congress permitted construction of the Keokuk power dam. An act two years later authorized provisions of a six-foot channel for navigation from the Missouri River to Minneapolis by "construction works, dredging, diking, canals and locks." In 1935, additional legislation was approved which authorized a nine-foot channel over the same river reach by means of locks and dams supplemented by dredging. The present dams now controlling the river resulted from this act. Engineering and environmental studies are currently being conducted to ascertain the feasibility of a twelve-foot navigation channel with year-long navigation.
Eleven permanent channel dams affect the river bordering Iowa, starting with Lock and Dam No. 9 at Lynxville to Lock and Dam No. 19 at Keokuk. Other Iowa dams are located at: No. 10, Guttenberg; No. 11, Dubuque; No. 12, Bellevue; No. 13, Clinton; No. 14, LeClaire; No. 15, Quad-Cities; No. 16, Muscatine; No. 17, New Boston; and No. 18, Burlington.
The river was originally inhabited by unbelievable numbers of clams (freshwater mussels) of various kinds. This abundance of clams was responsible for the establishment of a huge pearl button industry, the largest in the world, centered at Muscatine. Prior to dam construction, millions of tons of shells were taken, but since the nine-foot channel was established, suitable habitat for mollusks has largely disappeared under heavy deposits of silt, and the remaining button industry is supported primarily from man-made materials. By the early 1930`s, commercial clamming had virtually disappeared along the Mississippi.
Development and use of prepared clam shell pieces in the culture of pearls revived clamming in the mid-1970`s, but clam harvest was nowhere near that at the turn of this century. The reported catch of clammers licensed in Iowa waters of the Mississippi in 1976 was less than 300 tons, which held stable into the 1980`s. Most of this harvest was exported to the Orient for the seeding of pearl clams in the culture of these valuable jewels.
From an infant industry in the early river settlements, commercial fishing grew as the population in the midwest increased. Rapid transportation facilities and refrigeration, plus the introduction and establishment of carp in the 1880`s, put commercial fishing on the Mississippi River into a "big time" class. Commercial food-fish catches from the river provide a large proportion of the freshwater fish species consumed in the midwest and along the east coast today. Value of the fishery in Iowa exceeds well over one million dollars each year.
The fishing industry on the Mississippi supports wholly or, in part, many families. Over the past forty years, the annual catch of fish has not changed a great deal. The average commercial fish harvest for the five-year period 1943-48 was about three million pounds, the catch being made up of 47 percent carp, 22 percent buffalo, 15 percent catfish, 10 percent drum, and 6 percent other species. During the thirteen-year period 1970-82, total catch was slightly over 3.l million pounds each year. Species composition was 34 percent carp, 27 percent buffalo, 17 percent catfish, 15 percent drum, and 7 percent miscellaneous species. The most dramatic change has been the number of commercial fishermen licensed. Prior to 1970, seldom were there more than 400 licenses purchased. But in the mid-70`s, that number increased systematically until by 1983 over 2,250 Iowans were licensed to commercial fish -- most in the Mississippi River. Over the years, the number of full-time commercial fishermen has declined to only a few, while the number of part-time operators has increased dramatically.
Most of the commercial fish species are taken with nets and seines, although large numbers of catfish are caught on trotlines both in the river channel and in the backwaters and chutes. Commercial fishing is strictly regulated, with fishermen being required to license all gear and equipment and report the number and kinds of fish taken. Catfish populations, which are intensively fished, are protected from overharvest by a 15-inch minimum length limit. Prior to channelization of the Mississippi River, angling was undoubtedly much the same as that carried out in the larger interior Iowa streams at the present time.
With construction of the six-foot navigation channel in 1907, large numbers of wing dams and channel training structures jutting out from the shore into the current to deepen the channel were built. This profoundly changed earlier angling activities. Considerable fishing was done on the wing dams, where large numbers of crappie, northern pike, walleye, and smallmouth bass were taken. The wing dams, along with extensive shoreline riprapping, provided lush feeding grounds for fish, and they had a tendency to congregate in the areas where small forage fish found food and shelter. The six-foot channel probably had very little effect on fishing in the rapid chutes between the numerous islands in the Mississippi. Here, too, large congregations of foraging game fish were the source of excellent fishing.
With establishment of the nine-foot channel dams, most of the wing dams were submerged. Also, most of the rapid chutes between islands and even the islands themselves were inundated by backwaters, forever destroying many of the formerly productive game fishing grounds.
With the navigation locks and dams creating a series of lake-type pools in the river, there was a decided change in the make-up of fish populations. Fast-flowing water fish species, such as smallmouth bass, declined in abundance, and fishes that preferred more pond-like habitat, such as crappie, bluegill, walleye, carp and freshwater drum increased in abundance. The new channel dams also changed favorite locations for fishing.
Best fishing for species such as walleye, sauger, and paddlefish is directly in the tailrace of the navigation dams, especially in late spring and autumn. The popularity of fishing below the dams is accounted for by several basic factors that influence fish behavior. In the first place, for the large part of each year, the dams represent a physical barrier to fish movement -- mostly in the upstream direction. For some distance below each stucture, the bottom is scoured into a series of deep holes containing diverse fish habitats, giving a particularly favorable bottom environment with highly oxygenated water. These conditions afford excellent environment for forage fishes and other forms of fish food. Predacious sport fishes concentrate in these havens of easy feeding. Most of the dams are easily accessible for fishing either from the shoreline or by boat. Boat ramps and parking facilities are located within a short distance of all Mississippi locks and dams. There are a total of 58 launching facilities on the Iowa side of the river. Public lands usually stretch a considerable distance downstream and are open to fishing. Some restrictions for safety are in effect at all dams and must be obeyed.