Missouri River Native Fish
Sicklefin Chub, Sturgeon Chub, and Pallid Sturgeon
The sicklefin chub, sturgeon chub, and pallid sturgeon evolved within the diverse environments of the Missouri and Mississippi large river systems. Their preferred habitat has a diversity of swift, highly variable flows, high turbidity, and braided channels.
While all three species have been affected by the construction and operation of the six main stem dams built on the Missouri River, the chubs have been less vulnerable to these changes than the endangered pallid sturgeon.
The fundamental differences between these species have allowed the chubs to remain present in substantial numbers where turbidity levels and flow regimes still provide needed habitat conditions while the pallid sturgeon remains on the brink of extinction.
The following is a comparison of the three fish species:
The sicklefin chub, sturgeon chub, and pallid sturgeon prefer silty rivers with a diversity of depths and velocities forming braided channels, sand bars, sand flats, and gravel bars. All three have been affected by changes in the Missouri River and are extirpated from the 800 miles of the Missouri River that has been impounded and converted to reservoir habitat by the six main stem dams. The difference is the chubs have managed to effectively reproduce where habitat conditions allow. The pallid sturgeon, however, has been unable to adapt as well as the chubs to the present conditions of the Missouri River.
Life and reproduction cycles:
The chubs are short-lived minnows with a short reproductive cycle. Sicklefin and sturgeon chub are successfully reproducing and maintaining populations in widely dispersed areas. Pallid sturgeon are long-lived with individuals reaching 50 years of age. However, males do not reach sexual maturity for 7-9 years, with up to 3-year intervals between spawning. Females are not expected to reach sexual maturity for 7-15 years, with up to 10-year intervals between spawning.
Spawning home range:
Probably the most significant difference between the two species of chubs and the pallid sturgeon are their respective home range needs for successful spawning. The home range of the pallid sturgeon can extend over hundreds of miles. Pallid sturgeon migrate upstream to spawning areas and the subsequent larvae drift considerable distances downstream after hatching. For the pallid sturgeon larvae to survive they must find suitable downstream habitat. The home range needs for sicklefin and sturgeon chub to successfully reproduce is suspected to be considerably smaller and more localized. As a result, dams and reservoirs on the Yellowstone and Missouri Rivers that have resulted in the fragmentation of turbid, riverine habitat have had a greater impact on pallid sturgeon populations.
Pallid sturgeon populations are in danger of becoming extinct and this species is facing several roadblocks to recovery. In the Yellowstone and Missouri Rivers in North Dakota and Montana, pallid sturgeon are at or near the end of their reproductive cycles and there is no evidence that successful spawning is occurring. In the Lower Missouri and Mississippi Rivers limited reproduction has been recently documented by the collection of larval pallid sturgeon. However, information concerning the survival of larval pallid sturgeon is lacking. Hybridization rates between shovelnose and pallid sturgeon also appear to be increasing in this portion of the pallid sturgeonís range. Pallid sturgeon propagated in hatchery facilities have been stocked in several reaches of the Missouri River as an attempt to keep this species from edging closer to extinction.
FWS Sicklefin Chub Information
Other FWS Sturgeon Chub Information
Fish of the FWS Mountain-Prairie Region
Mountain-Prairie Region Web Site
National FWS Web Site