Endangered Sturgeon Struggle for Survival
The Pallid Sturgeon (above) is one of Missouri's endangered
species. (photo by Craig Gemming)
Habitat loss and over harvest have two of the three species of sturgeon found in Missouri fighting for survival. Sturgeon evolved over 150 million years ago during the Jurassic Era when dinosaurs roamed the earth. Unlike the other dinosaurs, however, sturgeon managed to survive the earthquakes, volcanoes and glaciers that formed North America. In fact, our endangered pallid and lake sturgeon have survived just about everything, that is, until now. In just the last 100 years, man has managed to drive them to the brink of extinction.
Description and Range
The sturgeons are a small group of primitive fishes with a wide distribution in the Northern Hemisphere. These prehistoric fish have an unusual appearance and resemble sharks in some respects. Sturgeon have long, streamlined, shark-like bodies, long bony snouts and are armored with lengthwise rows of sharp, bony plates called scutes. Their sucker-type mouth is located under their long bony snout. They also have four barbels that dangle from the snout in front of the mouth which are similar in appearance to the barbels or "whiskers" on a catfish. The barbels help the sturgeon locate food and find their way along the bottom.
The lake sturgeon (above) is another endangered sturgeon species found in Missouri. Lake sturgeon are protected by law and must be released unharmed immediately after being caught. (photo by Craig Gemming)
Pallid sturgeon (above) can live more than 40 years, reach five to six feet in length and weigh up to 65 pounds. The pallid sturgeon is endangered and protected by law. Pallid sturgeon must be released unharmed immediately after being caught. (photo by Craig Gemming)
The Shovelnose Sturgeon (above) is the only sturgeon species in Missouri that can be legally taken by anglers.
Three of the eight species of sturgeon that occur in North America are native to Missouri.
The three species that make Missouri's big rivers their home are the pallid sturgeon, the lake sturgeon and the shovelnose sturgeon. These sturgeon are primarily found in both the Missouri and Mississippi river basins. Both the pallid sturgeon and the lake sturgeon are endangered species. The shovelnose sturgeon, the most common of the three, has recently become a species of concern. A lot of factors have contributed to the decline of these species including habitat alterations by man to the Missouri and Mississippi rivers, over harvest, pollution, and hybridization. However, habitat loss and past, unregulated commercial fishing are the primary reasons for their decline.
Sturgeon Identification
All three species of sturgeon found in Missouri are similar in appearance, especially the endangered pallid sturgeon and the shovelnose sturgeon. Lake sturgeon and pallid sturgeon are endangered and protected by law. If caught, these two species must be immediately returned to the water unharmed. As a result, it is very important that anglers learn how to identify each species.
Lake sturgeon, often called rubbernose sturgeon, are not too difficult to identify. They have a short, rounded snout compared to the shovel-shaped snouts of the other two sturgeon species. Another key identifying characteristic of lake sturgeon is the barbels located in front of the mouth. The barbels on a lake sturgeon are smooth compared to the barbels on a pallid or shovelnose sturgeon which are fringed or serrated in appearance. These barbels help the sturgeon locate food and find their way along the bottom of the river. They look similar in appearance to the barbels or "whiskers" on a catfish. Young lake sturgeon are a mottled light and dark brown but adults are solid dark brown or slate in color.
A pallid sturgeon has
- a longer snout and head than the shovelnose sturgeon;
- barbels that form a crescent-shaped line at their bases;
- barbels attached closer to the mouth than the tip of the snout; and
- a skin-like, scaleless belly. In addition, the inner two barbels are usually much thinner and shorter than the outer two barbels. Young pallid sturgeon are very similar in color to adult shovelnose sturgeon. However, as pallid sturgeon mature, their sides and back turn grayish white in color.
Young pallid sturgeon and shovelnose sturgeon
look very similar in appearance, having the same color and body shape.
Many anglers and commercial fishermen often misidentify these two fish.
The best way to distinguish pallid sturgeon from shovelnose sturgeon is
to compare the barbels, belly and head length between the two species.
The pallid sturgeon (above) has a) a longer snout and head than the shovelnose
sturgeon; b) barbels that form a crescent-shaped line at their bases;
c) barbels attached closer to the mouth than the tip of the snout; and
d) a skin-like, scaleless belly. In addition, the inner two barbels are
usually much thinner and shorter than the outer two barbels. Barbels are
the long, tapering, cylindrical fleshy projections attached in front of
the mouth that look similar to the barbels or "whiskers" on a catfish.
Life History and Feeding Habits
Sturgeon are found in the Missouri and Mississippi river basins and spend most of their time in the
main channels of these large muddy rivers. These bottom-dwelling fish prefer strong current and live in areas having firm substrate. At certain times of the year, they can be found along sand and gravel bars or in deeply scoured holes. Sturgeon are highly adapted for life in our big
rivers having long, flat snouts, large pectoral fins and long, streamlined bodies. These unusual adaptations help the sturgeon move about and hold their position in the strong current.
Sturgeon are very long lived fish and mature slowly. Lake sturgeon can live up to 150 years, reach eight feet in length and a weight of 300 pounds. Pallid sturgeon can live more than 40 years, reach five to six feet in length and weigh up to 65 pounds. Shovelnose sturgeon, the smallest of the three species, can live over 20 years but rarely exceed 30 inches in length and a weight of 5 pounds. Sturgeon are very slow growing fish. An age and growth study done on sturgeon in the Missouri River by the Missouri Department of Conservation in 2001 revealed that 5 year old shovelnose sturgeon averaged 16.7 inches fork length and averaged 18.6, 18.6, 19.9, 21.1, 21.4, 22.4, and 23.1 inches in succeeding years. In 2002, during the same study, a biologist recaptured a shovelnose sturgeon that was originally tagged during a previous study by another biologist 23 years earlier! This fish turned out to be 37 years old!
Like most other long lived species, it takes sturgeon a long time to reach sexual maturity. It takes 15 to 20 years (25 - 40 lbs. in size) before a lake sturgeon can spawn for the first time; 7 to 12 years (6-12 lbs.) for a pallid sturgeon; and 5 to 7 years (2-3 lbs.) for shovelnose sturgeon. Sturgeon also have an unusual reproductive cycle in that they don't spawn every year like most other fish species. A female lake or pallid sturgeon only spawns once every 3 to 5 years and a female shovelnose sturgeon will spawn once every 2 to 3 years. Because of this fact, sturgeon are very susceptible to over harvest.
Sturgeon are extremely migratory fish and it's not unusual for them to travel hundreds of miles each year. Each spring, rising water levels and water temperature trigger sturgeon spawning migrations. It is not unusual to see shovelnose sturgeon move over 200 to 300 miles during their spring spawning migrations in the Missouri and Mississippi rivers. In April of 2003, a shovelnose sturgeon that was tagged on the Mississippi River during a research study at Cape Girardeau was taken by a commercial fisherman three weeks later near Hannibal. This fish was recaptured over 240 miles upstream of where it was originally tagged! Spawning for Missouri's sturgeons usually occurs when water temperatures are from 55 to 65° F with the peak of spawning occurring during the first week or two of May. During the spring in Wisconsin, lake sturgeon move up smaller streams or to rocky or gravelly areas in the rivers to spawn. Male sturgeon fertilize the adhesive eggs of the female as they are broadcast over these gravelly areas.
Sturgeon feed on the bottom using their highly protrusible mouth to suck up their food. Their diet consists primarily of larval aquatic insects, crayfish, snails, small clams, and small fish. As lake and pallid sturgeon grow larger, their dependency on small fish for food increases. However, sturgeon can be scavengers at times feeding on dead animal matter and are often caught by catfish anglers using worms or cut bait (cut up fish).
Threats to Survival
The development of the Missouri River from
1934 to 1972 for navigation and flood control drastically reduced critical
habitat needed by lake and pallid sturgeon. From Rulo, Nebraska to the mouth,
the Missouri River was shortened over 45 miles, lost 50% (121,740 acres
down to 60,954 acres) of its surface water acreage, and had 98% of its island
habitat eliminated! The photos above show the loss of fish habitat near
Indian Cave Bend, Nebraska.
Sturgeon currently face an uphill battle for survival. So why are sturgeon populations across the world on the decline? A lot of factors have contributed to the decline of these species including habitat alterations by man to the Missouri and Mississippi rivers, over harvest, pollution, hybridization and the introduction of exotic species. However, habitat loss and past, unregulated commercial fishing are the primary reasons for their decline.
Sturgeon are excellent barometers of big river environmental conditions because of their wide distribution, migratory nature, and diverse habitat requirements. For millions of years, sturgeon depended on the diverse habitat found in the Missouri and Mississippi rivers. Historically, our big rivers were wide and shallow consisting of braided channels, sand bars, gravel bars, sand shoals and numerous wetlands. These shallow water areas having low velocity flows were very important nursery and seasonal habitats for most riverine species including sturgeon. However, much of the 3,350 miles of riverine habitat in the sturgeons' range has been drastically altered and adversely impacted by man. Critical habitat necessary for lake and pallid sturgeon survival was all but destroyed during the development of the big rivers for flood control and commercial navigation. In just the last 65 years, 28% of the Missouri and Mississippi rivers have been impounded by dams creating unsuitable lake-like habitat. Deep, uniform, fast flowing, restructured channels now extend over 50% of each river's length and 95% of the wetlands have been eliminated. The Missouri River was actually shortened by over 45 miles; lost 50% (121,740 acres down to 60,954 acres) of its surface water acreage, and had 98% its island habitat eliminated! Only a fraction of the many sand bars remain and frequently these are under deep, fast moving water due to regulated flows mandated by the federal government and implemented by the U.S. Army Corps of Engineers. Regulated flows also eliminate or greatly reduce natural spring rises in water levels which are important spawning cues for most riverine fish including sturgeon. These same regulated flows also prevent low summer levels. The lack of shallow water areas having little or no flow during the summer deprive sturgeon of critical nursery habitat. Water quality below the dams is also much different now than prior to their construction. Today, water temperatures below the dams are much colder and turbidity has been greatly reduced. As a result of all these changes, most of the habitat needed by sturgeon has been eliminated or highly altered. In just 65 years, a micro-second in geologic time, man has so drastically changed the ecological balance of these rivers that many species are struggling for survival.
A commercial fisherman harvesting shovelnose sturgeon on the Mississippi River (photo by David Ostendorf)
The female shovelnose sturgeons are sacrificed so their eggs can be taken and processed for caviar. (photo by Craig Gemming)
Most sturgeon populations are teetering on the brink of extinction because of the world's insatiable appetite for caviar.
Unregulated commercial fishing has also had a big impact on the plight of our sturgeon.
Over harvest of lake and pallid sturgeon during the late 1800's marked the beginning of the decline for both of these species. At that time lake sturgeon were so common that they were indiscriminately killed to prevent damage to fishing nets. Rendering plants processed them for fertilizer and their oily flesh was even burned and used for fuel for steamboats. However, it wasn't long before people developed a taste for their flesh and eggs. By the mid 1900's, both species were considered rare and they have continued to decline since then.
The shovelnose sturgeon, unlike its larger "cousins", has managed to escape serious exploitation until just recently. The collapse of the Caspian Sea sturgeon fishery, which used to supply 90% of the world's caviar, has now focused attention on this species.
Like most other sturgeon fisheries, the demise of the Caspian Sea sturgeon fishery was primarily caused by over harvest. Now the caviar industry is targeting Missouri's shovelnose sturgeon and paddlefish as a major world wide source of caviar. Caviar prices have skyrocketed due to a lack of supply and the high demand. Prime Beluga caviar from the Caspian Sea was recently being sold for $1,500 per 14 ounce tin. A 14 ounce tin of shovelnose sturgeon caviar now retails for $225 to $300 and prices continue to climb. Surprisingly, the demand for shovelnose sturgeon continues to increase even though consumption of these fish or their eggs might cause health problems. The Missouri Department of Health has issued health advisories on shovelnose sturgeon for the last several years and recommends not eating them due to high contaminant levels.
The shovelnose sturgeon is the only species left that can be legally harvested. However, the caviar market crisis has refocused suppliers' attention on Missouri's shovelnose sturgeon population. As a result, we have seen a dramatic increase in harvest of shovelnose sturgeon and a dramatic decrease in abundance, especially in the Mississippi River. From 1998 to 2001, the pounds of shovelnose sturgeon harvested on the Mississippi River by commercial fishermen increased over 1000%. Commercial fishing for shovelnose on the Missouri River has also increased but at a slower rate than on the Mississippi River. Biologists are now very concerned about our shovelnose sturgeon population as a result of this dramatic increase in exploitation.
ROAD TO RECOVERY?
Recovery Plans
During the early 1990's, the Missouri Department of Conservation developed "action plans" for lake and pallid sturgeon to aid in their recovery. Goals of the plans are to reestablish self-sustaining populations so they can be delisted as endangered species and ultimately provide limited sport fisheries. These plans stress the restoration of both species through habitat improvement, artificial propagation, protection, research, management, and education. Over the last several years, the Department has been very active in implementing all aspects of these plans.
Habitat Restoration
Habitat restoration and improvement is one of the most important keys to the recovery of our endangered sturgeon. Department staff continue to work with the U. S. Army Corps of Engineers to improve habitat in our big rivers. Through the use of funds provided by the federal government, projects are being designed and installed which will increase the diversity of habitat for our endangered sturgeon. We are also working with the Corps of Engineers and many other state and federal agencies to better regulate flows on the Missouri River for the benefit of several threatened and endangered species. However, unless there is more of a change in river management these efforts will only have limited success. We believe a more balanced approach to river management can be found that will benefit all interests and still provide for more abundant fish and wildlife.
Since 1984, MDC's Blind Pony Fish Hatchery, a national leader in native sturgeon culture, has raised and stocked over 13,000 fingerling pallid sturgeon and 200,000 fingerling lake sturgeon into the Missouri and Mississippi Rivers.
Artificial Propagation
Another important key to restoration is the artificial propagation of pallid and lake sturgeon. Since 1984, MDC's Blind Pony Fish Hatchery, a national leader in native sturgeon culture, has raised and stocked over 13,000 fingerling pallid sturgeon and 200,000 fingerling lake sturgeon into the Missouri and Mississippi rivers. However, we can't depend on propagation alone for the recovery of these species. Rearing these fish in captivity is extremely difficult because of a variety of problems including difficulty acquiring brood stock, disease, and adequate funding. Even though the stocking program has helped, population densities for these two species still remain low. There is still a long way to go before the lake and pallid sturgeon populations get to the point where they are self-sustaining. Even though habitat restoration is the most important key to developing self-sustaining sturgeon populations, artificial propagation is still a high priority and the Department will continue the program until these species are restored.
Sturgeon Monitoring Project
Fisheries biologists (above) sampling for sturgeon during the Department's state wide longterm Sturgeon Monitoring Project. All sturgeon taken during sampling for the Project are being tagged to learn more about each species and monitor their status.
One of three types of spaghetti tags like those above are being inserted into sturgeon to gather information on things like movement, age and growth, population size, and exploitation. (photo by Craig Gemming)
The shovelnose sturgeon (above) has been tagged in the dorsal fin with a spaghetti tag. (photos by Craig Gemming)
The Missouri Department of Conservation has also recently started a long term, state-wide sturgeon monitoring project to track population trends for all Missouri's species. Since the mid 1990's, fisheries biologists across the state have been sampling and gathering information on sturgeon from both the Missouri and Mississippi rivers. As a part of this project, biologists are tagging all sturgeon to collect more information on population size, growth, movement, and harvest. Anglers catching a tagged lake, pallid or shovelnose sturgeon are asked to report the following information: species caught, date caught, where caught (river mile/nearest town), tag number, fork length, and weight. This information will help us achieve our goal of improving our sturgeon populations.
To report a tagged sturgeon call toll free 1-866-762-3338. For more information on sturgeon identification, contact the Missouri Department of Conservation, Resource Science Center, 1110 S. College Ave., Columbia, MO, 65201, 573-882-9880 or Central Region Office, 1907 Hillcrest Dr., Columbia, MO, 65201, 573-884-6861.
Proper management of Missouri's sturgeon populations is important to their recovery. Endangered pallid and lake sturgeon are illegal to harvest and have been protected by law for many years. MDC has also intensified its efforts to better regulate the shovelnose sturgeon fishery. Shovelnose sturgeon commercial harvest regulations have become more restrictive over the past few years but even with these new regulations the population has continued to decline. As a result, the Department of Conservation will be implementing even more restrictive regulations in the near future. However, even the most restrictive regulations won't solve all of the problems facing Missouri's sturgeon population.
OUR STURGEONS' FUTURE
It's hard to believe that these fish that have thrived for 150 million years have been brought to the brink of extinction in just the last century. We need to take a step back and learn from our past mistakes if we hope to have any chance of restoring our lake and pallid sturgeon populations.
Recovery will be difficult and require a concentrated effort to solve the many problems affecting our sturgeon populations. Restoring habitat and balancing the management of our big rivers is an important first step in the right direction. To do this, will require a cooperative effort from everyone. All big river stakeholders including the public, conservation/environmental groups, Indian tribes, politicians/government officials, agriculture, barge industry, recreational interests, state and federal agencies, and others must work together to find and implement solutions for the sturgeons' recovery. State and federal agencies must also continue to work together on protection, research and management of sturgeon. If we can, Missouri's aquatic dinosaurs will win their fight for survival.
