Photo by Ken Bouc; Nebraska Game and Parks Commission

Status: Endangered (55 Federal Register 36641) on September 6, 1990.

Description: P Pallid sturgeons have a unique dinosaur-like appearance. They have a flattened snout, long slender tail and are armored with 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.

Current Range and Status: Today, pallid sturgeons are scarce in the upper Missouri River above Ft. Peck Reservoir; scarce in the Missouri and lower Yellowstone Rivers between Ft. Peck Dam and Lake Sakakawea; very scarce in the other Missouri River reservoir reaches; scarce in the Missouri River downstream of Gavins Point Dam; scarce but slightly more common in the Mississippi and Atchafalaya Rivers; absent from other tributaries.

Habitat: Pallid sturgeons evolved and adapted to living close to the bottom of large, silty rivers with natural a hydrograph. Their preferred habitat has a diversity of depths and velocities formed by braided channels, sand bars, sand flats and gravel bars.

Life History and Reproductive Biology: Sexual maturity for males is estimated to be 7-9 years, with 2-3 year intervals between spawning. Females are not expected to not reach sexual maturity until 7-15 years, with up to 10-year intervals between spawning. Pallid sturgeons are long lived, with individuals perhaps reaching 50 years of age.

Reasons for Decline: All of the 3,350 miles of riverine habitat within the pallid sturgeon=s range have been adversely affected by man. Approximately 28 % has been impounded, which has created unsuitable lake-like habitat; 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. Commercial fishing and environmental contaminants may have also played a role in the pallid sturgeon's decline.

Recent Recovery Activities: In 1997, through the combined effort of two Fishery Assistance offices, two National Fish Hatcheries, one Ecological Services office, and two State game and fish departments (North Dakota and Montana), two female and three male pallid sturgeons were spawned. Spawning pallid sturgeons from the upper Missouri River had been attempted since 1988, but to no avail. Currently, approximately 5,000 young pallid sturgeons are being reared at Gavins Point NFH. In August, 1998, the Fish and Wildlife Service and state game and fish departments from North Dakota and Montana will stock up to 1,500 of these fish in two areas; at sites near the Missouri and Yellowstone River confluence, and in the Missouri River upstream of Ft. Peck Reservoir in Montana. This release will be the first under a multi-agency 6-year plan to augment doomed adult populations. Since pallid sturgeons do not reach maturity and spawn for several years, we must stock now so that we have adults in the wild as habitats are restored. Without artificial propagation in hatcheries and subsequent population augmentation, this population will likely be extirpated. The juvenile pallid sturgeon we stock under this plan will be the founder population for recovery.

3/98

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