Paddlefish, Sturgeon, and Bigheaded Carps – Status, Biology, and Management in the Mississippi River

Paddlefish (Polyodontidae), sturgeon (Acipenseridae) and bigheaded carps (Cyprinidae: Hypophthalmichthys spp.) are taxa shared by the Yangtze and Mississippi River Basins.  In the Yangtze, native paddlefish (Psephurus gladius) are functionally extinct, sturgeon are maintained through stocking, and bigheaded carps (H. nobilis and H. molitrix) declining.  In Mississippi River, native paddlefish (Polyodon spathula) are secure, pallid sturgeon (Scaphirhynchus albus) endangered, shovelnose sturgeon (S. platorhynchus) “threatened,” and lake sturgeon (A. fulvescens) locally imperiled, although large robust populations of all these species exist in portions of their ranges; introduced bigheaded carps are invasive and abundant throughout their range.   Paddlefish and sturgeon are habitat specialists having long periods of maturation (> 7 years) and infrequent reproduction (every 2-3 years). In areas lacking adequate spawning and rearing habitat populations are maintained principally by stocking hatchery-reared fish.  In areas with large free-flowing, hard-bottomed channels, used for spawning and rearing habitat (e.g., free-flowing Mississippi River), populations are maintained principally by regulating harvest and providing rearing habitats (e.g., access to backwaters, secondary channels).  Bigheaded carp are habitat generalists with short periods of maturation (2-3 years) and frequent reproduction.  Rearing habitat for bigheaded carp is virtually unlimited (e.g., main channel, secondary channels, tributaries, backwaters, seasonal pools) and rangewide management is unlikely, though local control is possible through containment (e.g., electrical and hydraulic barriers) and intensive harvest.