Reproductive ecology of Asian Carp in Southeastern Iowa rivers


Principal Investigator:

Michael J. Weber

Clay L.Pierce

Student Investigator:

Aaron Matthews (M.S.)

Carlos Camacho (M.S. Graduate)


Kim Bogenschutz, Iowa DNR

Jason Euchner, Iowa DNR


July 2013 to June 2018

Funding Source(s):

Iowa Department of Natural Resources

US Fish and Wildlife Service


Goals and Objectives:

Evaluate Asian carp reproduction (fecundity, larval and juvenile densities) and recruitment in select Iowa rivers, including the Mississippi, Des Moines, Skunk, Iowa, and Cedar rivers



Adult gonadosomatic index and gonad development indicated the majority of Asian carp spawning occurred in late May through June. Back calculated spawn dates from eggs and larvae suggest that peak spawning occurs during late May and June, coinciding with a substantial decrease in adult GSI and increase in post spawn females; however, spawning occured as late as August in tributaries. Back-calculated egg and larval spawn dates were within the spawning optimum when water temperatures were 18 to 30 °C and channel velocities were 0.7 m/s or higher. Spawning occurred on rising and falling limbs of the hydrograph at 24 and 48 h intervals, indicating a rising hydrograph was not necessary for spawning. Densities of eggs and larvae were higher in downriver section compared to the upriver section within each tributary during both years. Densities among tributaries were similar in 2014 and but were significantly higher in the Des Moines River than the Iowa and Skunk rivers during 2015. Densities among the three confluence sites were similar for the Iowa and Skunk during each year. However, densities among sites associated with the Des Moines River confluence were higher in the mainstem Upper Mississippi River in 2014 and higher in the tributary site near the mouth in 2015. Collectively, this study documents the first observations of Asian Carp spawning in Upper Mississippi River tributaries in Iowa. Asian Carp reproduction in the Upper Mississippi River tributaries and subsequent establishment could provide sources of recruitment for the impounded sections of the Upper Mississippi River and other areas of poor reproduction to further expand their distribution. 


Future Plans:

Egg, larval, and adult Asian Carp sampling was expanded north to pool 14 during 2016 to try to detect the leading edge of reproduction in the Upper Mississippi River. These samples are still being processed in the laboratory.  Additional sampling will occur in 2017.

07/01/2013 to 06/30/2018