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Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Endangered

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Potential Minimum Threshold For Pallid Sturgeon Relative Condition In The Lower Missouri River, Kirk D. Steffensen May 2018

Potential Minimum Threshold For Pallid Sturgeon Relative Condition In The Lower Missouri River, Kirk D. Steffensen

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Pallid Sturgeon (Scaphirhynchus albus) condition has declined in the lower Missouri River but the cause and the effects of this decline remain uncertain. Adult Pallid Sturgeon are becoming reproductively ready less frequently and sub-adult Pallid Sturgeon are likely delaying sexual maturation. Even more concerning, Pallid Sturgeon capture rates have declined the past two years (i.e., 2016 and 2017), despite the ongoing Pallid Sturgeon stocking program. Several Pallid Sturgeon that have been captured are visually emaciated but a minimum condition threshold has not been described. Therefore, the aim of this study is to present a potential lethal condition level for …


The Status Of Fishes In The Missouri River, Nebraska: Selected Ancient Fishes, Kirk D. Steffensen Dec 2015

The Status Of Fishes In The Missouri River, Nebraska: Selected Ancient Fishes, Kirk D. Steffensen

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Several ancient fish species have inhabited the Missouri River and its tributaries for thousands of years prior to major mainstem modifications and fragmentation. However post-anthropogenic modifications, populations of these ancient fish species have been highly diminished. Therefore, the objective of this study was to use historic and current ichthyological records to determine the past and present status for Chestnut Lamprey Ichthyomyzon castaneus, Silver Lamprey Ichthyomyzon unicuspis, Bowfin Amia calva, American Eel Anguilla rostrata, and Burbot Lota lota. Currently, these species are rarely captured and perhaps extirpated from Nebraska waters.


The Status Of Fishes In The Missouri River, Nebraska: Pallid Sturgeon (Scaphirhynchus Albus), Kirk D. Steffensen, Dane A. Shuman, Robert A. Klumb, Sam Stukel Sep 2014

The Status Of Fishes In The Missouri River, Nebraska: Pallid Sturgeon (Scaphirhynchus Albus), Kirk D. Steffensen, Dane A. Shuman, Robert A. Klumb, Sam Stukel

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Anthropogenic alterations to the Missouri River have placed the Pallid Sturgeon (Scaphirhynchus albus) population in jeopardy and contributed to their listing as an endangered species. Pallid sturgeon were always less common than the sympatric Shovelnose Sturgeon (S. platorynchus); however, Pallid Sturgeon seemed to be more affected by river alterations as the river sturgeon ratio has become more skewed towards Shovelnose Sturgeon. Shortly after listing, population augmentation with hatchery produced Pallid Sturgeon began to supplement the diminishing wild population. Therefore, the objective of this study was to present the current population status of the Pallid Sturgeon in …