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Monday, January 29 • 2:40pm - 3:00pm
ASIAN CARP: Reproductive Potential of Silver and Bighead Carp in the Upper Mississippi River

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AUTHORS. Allison Lenaerts, James Lamer, Cortney Cox, Boone La Hood - Western Illinois University; Kevin Irons, Illinois Department of Natural Resources

ABSTRACT. Invasive silver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) are abundant throughout most of the Mississippi River Basin and are very prolific spawners. Asian carp abundance in the Mississippi River above Lock and Dam 19 is low relative to reaches below the dam. Understanding the reproductive potential (i.e., gonadalsomatic index (GSI) and fecundity) of these low density, poorly understood populations is important to inform Asian carp management in the Upper Mississippi River.  We examined and compared GSI of silver carp (females: n= 261, males: n= 430) and bighead carp (females: n= 99, males: n= 235) among pools 17-20 of the Mississippi River with stage IV ovaries. Eggs were removed from three locations in one ovary per fish (silver carp, n=155 and bighead carp, n= 76), counted, and weighted to estimate fecundity. Bighead and silver male GSI is not significantly different between pools. Female silver carp GSI is significantly higher in leading edge populations and decreases as densities increases downstream, Pools 17 ?19 (p=0.000), Pools 17 ?20 (p=0.000), and Pools 18 ? 20 (p=0.001). Bighead carp females have a significantly higher GSI in Pool 18 than Pool 20 (p=.0213). Silver carp averaged 794 eggs/g (sd=137.39, se±11), and bighead carp averaged 468 eggs/g (sd=122.56, se±14) across all pools. Differences in GSI may reflect a release from density dependent factors within the leading edge. Lower densities may allow for more allocation of resources to gonadal growth versus somatic growth above Lock and Dam 19. 

Monday January 29, 2018 2:40pm - 3:00pm CST