Conservation of Pallid Sturgeon

The pallid sturgeon (Scaphirhynchus albus) is a critically endangered species native to the Missouri and lower Mississippi River drainages.  Throughout their entire range, pallid sturgeons co-occur with shovelnose sturgeon (S. platorynchus) a species that is morphologically very similar and far more numerous.  In the picture on the right the top fish is a shovelnose sturgeon and the bottom fish is a pallid sturgeon.  While pallid sturgeon is federally protected, shovelnose sturgeon is commercially and recreationally harvested in several states including Illinois.  There is a considerable amount of morphological and genetic overlap between the two species, in part due to hybridization, especially in the lower Missouri and Mississippi rivers. In the upper Missouri River hybridization is less common, however all remaining wild pallid sturgeon are very old and reaching the ends of their lifespans. Several ongoing projects involving pallid sturgeon conservation are listed below.

Development of Scaphirhynchus SNP Markers Jen Eichelberger and Matt Krampe Single Nucleotide Polymorphisms (SNPs) are single base substitutions which can be scored rapidly and inexpensively, once they are found. We are developing SNP markers associated with known functional genes in pallid and shovelnose sturgeon as a means of more efficiently discriminating between the species and their hybrids. The sequences we are generating may ultimately be useful for phylogenetic studies and for gene expression studies to understand biologically meaningful differences between pallid and shovelnose sturgeon and between genetically distinct stocks of pallid sturgeon. This work is funded by the US Geological Service.

Identification of Larval Sturgeon Ryan Boley Understanding the distribution and habitat use of pallid sturgeon during their first year of growth is crucial for determining what habitat features of the altered Mississippi and Missouri rivers are influencing pallid sturgeon recruitment. Ryan Boley is using genetic markers to identify where and when young pallid sturgeon occur relative to habitat data including flow, substrate, and basin morphology. This work is funded by the Army Corps of Engineers St. Louis District.

Development of a Captive Broodstock Genetic Management Plan for Upper Missouri Pallid Sturgeon Melody Saltzgiver and Josh Geltz Pallid sturgeon from the upper Missouri River have not successfully reproduced in the wild for several decades. All remaining wild fish, of which there are perhaps as few as 200 left, are very old and are approaching the ends of their natural lifespans. The only way to preserve this genetically distinct stock is through captive spawning and relase of hatchery-reared offspring, which seem to be surviving well in the wild. Hatchery rearing of fish from the wild has risks including inbreeding due to crosses between related individuals or decreases in the genetic effective population size, which will lead to inbreeding in future generations. Graduate student Melody Saltzgiver (left) aided by undergraduate assistant Josh Geltz (right) are genetically analyzing wild broodstock parents and their offspring to help develop a genetic management plan to conserve as much genetic variation as possible in the wild stock for future generations of pallids and humans. This research is funded by the US Fish and Wildlife Service and the US Department of Energy/Western Area Power Administration.

Genetic Discrimination of Pallid and Shovelnose Sturgeon Aaron SchreyPh.D. 2007 Critical to the conservation of shovelnose sturgeon is the development of tools to distinguish between pallid sturgeon, shovelnose sturgeon, and hybrids if they exist. Aaron Schrey (Ph.D. 2007,above) scored DNA microsatellite loci as a means of genetically discriminating between pallid and shovelnose sturgeons. Multilocus genotypes of sturgeons collected from the Middle Mississippi River (between Cairo Illinois and the confluence of the Missouri River) cluster into two discrete groups that are largely concordant with morphological identification of specimens (graph, upper right).  Pallid and shovelnose sturgeons from the Middle Mississippi River are reproductively isolated to some degree, with the presence of genetic and morphological intermediates characteristic of introgressive hybridization.  There is genetic structuring of pallid sturgeons (lower right) with fish from the upper and middle Missouri rivers clustering to different genetic groups than those in the lower Missouri and Mississippi. This research was funded through the US Fish and Wildlife Service and the Army Corps of Engineers St. Louis District, and USGS.

More Sturgeon Information:

US Fish and Wildlife Service Endangered Species Program

USGS Columbia Environmental Research Center

Fishbase

Montana Fish and Wildlife

Smitsonian Magazine article

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the US Fish and Wildlife Service, USGS, or the US Army Corps of Engineers.

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Last updated: 08-January 09 / EJH