Monitoring the Mississippi

By Bob Hrabik | January 2, 2001
From Missouri Conservationist: Jan 2001

When Europeans first gazed upon it, the Mississippi River looked much different than it does today. In 1797, Nicolas de Finiels, who traveled the river from the mouth of the Ohio River to St. Louis, described, "many lengthy detours, endless islands, bends where the current moves as swiftly as lightning, innumerable sand bars, snags, fallen trees here and there, rocks, sometimes in the channel, sometimes along the banks."

Even then, people were interested in using the river for commerce. Several historical accounts describe how commercial harvesters cleared the river islands of trees. In the interest of commerce and easy navigation, the river was made straight and deep, or as straight and deep as dikes, rip-rapped banks and dredging could make it.

The result of this transformation was a river that no longer could meander within its floodplain. The river's natural processes of eroding and flooding, which created new habitats from old, were either destroyed or arrested. The river's ecological health suffered at the expense of economic growth.

To better understand the effects of human induced changes on the river's ecology, Congress in 1986 created the Environmental Management Program. The program is designed to provide river managers with information and tools to help them balance the competing interests of navigation, industry, conservation and recreational uses of the river.

The EMP consists of two major elements or programs: Habitat Rehabilitation and Enhancement and Long Term Resource Monitoring. Five basin states, Illinois, Iowa, Minnesota, Missouri and Wisconsin, maintain Long Term Resource Management field stations to collect data along the 1300-mile Upper Mississippi River system.

The Open River Field Station, near Cape Girardeau, began operating in January 1991. It was the last of six field stations added to the Long Term Resource Management Program. At full staff, the field station supports six permanent employees specializing in fisheries biology, limnology (water quality), invertebrates, botany and ecology.

"Open river" refers to the stretch of the Upper Mississippi River not impounded by dams. It lies between the confluences of the Missouri and Ohio rivers. The open river study area is between river miles 30 and 80 (roughly 25 miles north and south of Cape Girardeau). The station's staff also conduct specific studies beyond their study area.

Field station biologists collect information on water quality, water levels and flows, bathymetry, vegetation, fish, invertebrates, sediment types and distribution, sediment and nutrient transport and land cover and use. Some of the things they look for include changes in aquatic vegetation, fish communities, water quality and sediment, as well as navigation impacts, nutrient transport and water level fluctuations.

All field stations use the same gear and methods to ensure consistent and reliable data. The data they collect is transferred electronically to the United States Geological Survey's Upper Midwest Environmental Science Center in La Crosse, Wisconsin.

Thanks to the information collected by the field stations, the environmental science center now is in possession of the largest source of nutrient transport data on the Upper Mississippi. This information is being used to address what is known as the "dead zone" in the Gulf of Mexico.

Years of fertilizer use in the Upper Mississippi River basin has helped create a large area outside the mouth of the Mississippi River so depleted of oxygen it cannot support life.

Data collected by the field stations helps us understand the sources of the nutrients, how they are transported and how we can manage the problem.

The Open River Field Station works to blend the monitoring program with goals of the Missouri Conservation Department. The monitoring program accounts for most of the effort, but the staff also is active in research,coordination with other agencies and outreach and education.

The research is primarily dedicated to developing new and more efficient sampling techniques and to understanding the ecology of rare animals or communities in the river. Because the Mississippi River near Cape Girardeau is big, deep, muddy and swift, biologists have had difficulty studying it. Until the Open River Field Station was established, virtually nothing was known about the river's ecology and how to adequately sample it.

Open River Field Station biologists are continually developing new techniques to capture organisms that live in these waters. One new sampling technique is a trawl designed to capture small fishes and the young of large fishes. The experiments have led to discoveries of rare animals thought to be gone, or nearly so, in the open Mississippi River.

In 1998, Open River Field Station biologists used the trawl to capture a pallid sturgeon measuring only about 3 inches long. It was the first time a young-of-the-year pallid sturgeon was captured in the wild.

Pallid sturgeon belong to an ancient order of fishes that have managed to survive to modern times. They were once common in the Mississippi and Missouri rivers. Around the turn of the century, this species comprised a large percentage of the commercial fishery catch in those rivers.

Pallid sturgeon numbers began to decline in the early 1900's, probably from overharvesting. Since then, habitat in the Mississippi and Missouri rivers has been greatly altered, which may account for the low numbers we see today.

The experimental trawl was originally developed to capture several species of rare big river chubs (minnows). Specifically, these included sturgeon chubs and sicklefin chubs.

Both species live only in big, turbid rivers. In Missouri, they are found only in the Missouri and Mississippi rivers.

Historical data suggests that both species declined in the open Mississippi River and in much of the Missouri River. Both species are candidates for federal listing and remain species of special concern in Missouri becausethe specific habitat they require is rare in our big rivers.

In 1991, Open River field station biologists "rediscovered" a large freshwater prawn thought to have be extinct in the Upper Mississippi River. The prawn, called the Ohio shrimp, grows large enough for humans to eat. They were once so common in the Mississippi River that they supported commercial fisheries in several small towns along the river. Many of these small towns held annual "shrimp fries."

The species began to decline sometime in the late 1930s. The last known collection of Ohio shrimp in the open Mississippi River was near Cairo, Ill., in 1962.

Discoveries like that of the Ohio shrimp suggest a lack of information about invertebrates in the Mississippi River. Furthermore, Open River Field Station biologists recently captured several larval specimens of pseudiron mayfly from a Mississippi River gravel bar. This is the first time this species has been found in Missouri's portion of the Mississippi River. New research is helping develop even better methods of sampling for big river invertebrates.

The Long Term Resource Monitoring and the Open River Field Station programs have caught the attention of river ecologists around the world. In 1993, during the biggest flood in years, scientists from Russia's Institute of Biology of Inland Waters visited the Open River Field Station.

Dr. Arthur Poddubney, head of the Department of Ichthyology, and Gregory Scherbina, from the Laboratory of Aquatic Invertebrate Ecology, toured the facility and flooded areas. During their visit, we exchanged much information about our respective programs on the Mississippi and Volga rivers.

In 1995, Peruvian biologists Enrique Rios Tsern and Norma Flores Arana of the Universidad Nacional de al Amazonia Peruana visited twice. They are responsible for "managing" the Amazon River and were interested in our procedures.

By definition, monitoring something means watching, observing or checking it for some purpose. This may seem easy, but in the case of the Mississippi River, which has an imposing and sometimes harsh environment, special skills and gear are required to detect changes.

Furthermore, biologists must take special care when designing a monitoring program. They have to be careful not to bias the data, which would lead to erroneous conclusions. Finally, because monitoring programs are designed to detect broad environmental changes over many years (long term), they cannot determine the direct causes of biological trends. Therefore, a certain type of research, called "cause and effect," should be added to a monitoring program to help explain long-term changes. This is the program used by the Open River Field Station.

Since the establishment of the Open River Field Station, much has been learned about the ecology of the open Mississippi River. Trend data are only about 10 years old, so definitive statements about trends in the health of the river may be premature. However, the data seems to indicate little short-term change in the aquatic communities and water quality of the open river. Most damage to animals and their habitat occurred long before the monitoring program was established.

Because of a dearth of information about the open Mississippi River, biologists can't be sure how many species may have been extirpated from the river or to what degree the community of animals are disturbed. Because no one had ever taken the time to look, some animals thought to be rare or extirpated may not be. The Long Term Resource Monitoring Program will provide more information about existing populations over time.

The benefits to Missourians from the Environmental Management Program include free information and aerial photos, the construction of habitat rehabilitation projects to improve the river's environmental conditions and better fishing.

In addition, partnerships have been established that have helped bring environmentalists, engineers and industrialists together to balance the river's delicate ecology with economic needs. This is important, considering recreational uses (including sportfishing) of the Upper Mississippi River account for more than $1.2 billion annually in direct expenditures.

The Mississippi River will never look like it did before European settlement, nor is that one of the goals of the Environmental Management Program. However, we do need to know how the river is reacting to human activities so we can manage it for the benefit of all who depend on it.

Recognizing the value of the data collected by the field stations to commerce, navigation and recreation, Congress has authorized the Environmental Management Program into perpetuity. As the years go by, we will know more and more about our country's most valuable river.

This Issue's Staff

Editor - Tom Cwynar
Managing Editor - Bryan Hendricks
Art Editor - Dickson Stauffer
Designer - Tracy Ritter
Artist - Dave Besenger
Artist - Mark Raithel
Photographer - Jim Rathert
Photographer - Cliff White
Staff Writer - Jim Low
Staff Writer - Joan McKee
Composition - Libby Bode Block
Circulation - Bertha Bainer