Paddlefish Genetics Study

The paddlefish (Polyodon spathula) is a large, planktivorous fish historically found throughout the Mississippi and Missouri River systems, the Mobile (AL) drainage, and portions of the Great Lakes.  The paddlefish represents one of the oldest and most obscure of North America’s freshwater fish species.  Severe alterations to large rivers over the last 100+ years and recent threats associated with increased harvest demand for roe and smoked meat coupled with competition from exotic species (i.e., bighead and silver carp) has compromised the sustainability of natural stocks of paddlefish.

To date, knowledge of paddlefish genetic diversity and delineation of potential genetic management units (GMUs) has been lacking.  This information is prerequisite for effective, science-based management of the paddlefish resource based on the stock concept and population dynamics.  The benefits of definitive paddlefish GMUs include more efficient propagation and supplementation regimes, minimizing outbreeding and inbreeding risks, superior broodstock management and choice strategies, etc.  Furthermore, genetic analyses can provide key biological information including estimates of paddlefish effective population sizes, estimates of the number of spawning parents, mean relatedness of a cohort, and sex-specific differences in dispersal.  Our office initiated a collaborative study to determine the variability of paddlefish genetics in Lake Francis Case and the Missouri River below Fort Randall and Gavins Point dams in 2004 and continued to collect tissue samples during 2005.  Genetics analyses will be conducted by Dr. Brian Sloss, Assistant Unit Leader of the Wisconsin Cooperative Fishery Research Unit, at the University of Wisconsin, Stevens Point.  Additional tissue sample collections have been coordinated with South Dakota Department of Game Fish and Parks and the Nebraska Game Fish and Parks Commission.