Inferring Pallid Sturgeon (Scaphirhynchus albus) Demographic History to Assist Recovery Efforts

Anthropogenic habitat alterations, primarily during the early 1900s through the 1960s, have been identified as one of the major threats to pallid sturgeon (Scaphirhynchus albus) in the Missouri River.   The absence of documented natural recruitment led to establishment of a conservation augmentation program in the late 1990s.  Long generation time has provided an opportunity to conserve pallid sturgeon genetic diversity via a successful captive breeding program.   However, until now, historical pre-dam population size data were lacking making defining recovery goals difficult.  This presentation will provide a general overview of the conservation augmentation program and briefly discuss a recently completed effort using coalescent based modeling of allele size distribution to assess levels of gametic disequilibrium and heterozygosity at 17 microsatellite loci to infer demographic history of a population of pallid sturgeon in Montana and North Dakota.  These methods provide a framework for integrating genetic based estimates of historic population size into recovery efforts for endangered species and demonstrate its application to a highly endangered population of pallid sturgeon from the upper Missouri River.