Chapter 8: Paddlefish Caviar: Trends in Global Value and Genetic Tools to Safeguard Resources
Steven R. Fain
Abstract.—With the break-up of the Soviet Union in 1991, and the unhalting collapse of the Caspian Sea sturgeon fisheries from desperate management policies to maintain production, law enforcement investigators in the U.S. encountered increased poaching of Paddlefish Polyodon spathula caviar throughout the Mississippi River basin. The steady rise of caviar prices has encouraged the illegal, unreported, and unregulated (IUU) taking of Paddlefish and the same over-harvesting that devastated the Caspian and Atlantic Sturgeon caviar fisheries of the past. International, federal and state regulations have been enacted to conserve Paddlefish, but still allow responsible commercial development where supported by population status. However, critical to conservation plans, there is not general agreement as to how Paddlefish populations are structured. Genetic research efforts have provided conflicting results with different demographic histories suggested by nuclear microsatellite and mitochondrial DNA (mtDNA) markers. Nor is it possible to answer key law enforcement questions in the commercialization of Paddlefish—to differentiate wild from aquaculture derived Paddlefish products in trade, or to distinguish the geographic origins of wild Paddlefish and their products in order to identify areas of poaching activity. This review summarizes the findings of genetic studies that have addressed questions of genetic diversity and phylogeographic structure in Paddlefish, as well as the need for further study of mtDNA diversity and fine scale structure of nuclear variation. Lastly, the use of available resources for genetic tagging assessments, and expressed sequence tag (EST) marker discovery to resolve Paddlefish phylogeography are also discussed.