Official Status: Listed as endangered (55 Federal Register 36641) on September 6, 1990.
Description: Pallid sturgeons have a unique prehistoric appearance. They have a flattened snout, long slender tail, and are armored with five lengthwise rows of bony plates instead of scales. Their mouth is toothless and positioned under the snout for sucking small fishes and invertebrates from the river bottom. Pallid sturgeons can weigh up to 80 pounds and reach lengths of 6 feet, whereas the closely related shovelnose sturgeon rarely weights more than 8 pounds. The back and sides of pallid sturgeons are grayish-white versus the brown color of the shovelnose sturgeons.
Historic Range: Historically, pallid sturgeons were found in the Missouri River from Fort Benton, Montana, to St. Louis, Missouri; in the Mississippi River from St. Louis to the Gulf; in the Yellowstone River from Miles City, Montana, to the Missouri River, and in the lower reaches of other large tributaries such as the Yellowstone, Platte, Kansas, Ohio, Arkansas, Red, and Sunflower; and in the first 60 miles of the Atchafalaya River.
Current Range and Status: Today, pallid sturgeon populations are fragmented by mainstem dams on the Missouri River. The pallid sturgeon are scarce in the upper Missouri River above Ft. Peck Reservoir; in the Missouri and lower Yellowstone Rivers between Ft. Peck Dam and Lake Sakakawea; in the Missouri River downstream of Gavins Point Dam; and in the Mississippi and Atchafalaya Rivers.
Habitat: Pallid sturgeons evolved and adapted to living close to the bottom of large rivers with high turbidity and a natural hydrograph. Their preferred habitat has a diversity of depths and velocities formed by braided channels, sand bars, islands, sand flats and gravel bars
Life History and Reproductive Biology: Sexual maturity for males is estimated to be 7-9 years with up to 3 years between spawns. Females are not expected to reach sexual maturity until 7-15 years, with up to 10-year intervals between spawning. Pallid sturgeons are long lived, with individuals perhaps reaching 60 years of age or more
Reasons for Decline: All of the 3,350 mile of river habitat within the pallid sturgeon's range have been adversely affected by our attempts to tame the rivers. Approximately 28% has been impounded, which has created unsuitable lake-like habitat and blocked migration routes; 51% has been channelized into deep, uniform channels; the remaining 21% is downstream of dams which have altered the river's hydrograph, temperature and turbidity. Hybridization with the more common shovelnose sturgeon is a threat to the species and may be attributed to the modifications occurring to the habitats used by both species. Commercial fishing and environmental contaminants may also played a role in the pallid sturgeon's decline.
Recent Recovery Activities: Population augmentation and propagation has been a focus of scientists since the mid 1990's when it was realized that recruitment of juvenile fish into the permanent population is not occurring at levels that will sustain the species. The current populations are composed of older fish that will die off in the near future. Since pallid sturgeons do not reach maturity until possibly 12 to 15 years of age, and spawning interval may be several years apart, we must stock now so that we have adults in the wild when habitats are restored. The juvenile pallid sturgeon we stock today will be the breeding population for future recovery efforts. However, habitat restoration will be essential to realize the recovery of this species. Habitat restoration, life history information and threats to the species remain in the forefront of recovery issues.