Spatiotemporal Variation in the Magnitude of Reproduction by Invasive, Pelagically Spawning Carps in the Illinois Waterway

Joseph J. Parkos, Steven E. Butler, Gregory D. King, Anthony P. Porreca, David P. Coulter, Ruairi MacNamara, David H. Wahl

Research output: Contribution to journalArticlepeer-review


The relationship between the magnitude of reproduction and adult density of pelagically spawning carp (PSC) species (bigheaded carp Hypophthalmichthys spp., Grass Carp Ctenopharyngodon idella, and Black Carp Mylopharyngodon piceus) and the influence of environmental factors on this relationship are valuable information for management and control of these highly invasive cyprinids. Six years of standardized monitoring for PSC reproduction and adult density in navigation pools of the Illinois Waterway (IWW; the Illinois River and its connection to Lake Michigan through the Des Plaines River and Chicago Area Waterway System), in conjunction with removal efforts in the upper IWW, where there is limited fish movement between pools, provided an opportunity to deepen our understanding of factors affecting the reproductive productivity of this invasive assemblage. Reproductive activity most commonly occurred in May and June, with the magnitude of reproduction in June far exceeding that occurring in other months. The highest egg counts were found within a 72-km zone containing the hydromorphological transition between the upper and lower Illinois River, with the majority of PSC larval drift occurring below this zone in the lower Illinois River. Magnitude of reproduction increased nonlinearly with adult PSC density, declining at high adult densities. Annual egg counts were also higher in years that combined more variable spring discharge with higher accumulated degree-days through June. The density-dependent reproduction exhibited by PSC implies that any stock–recruitment variation observed for these species needs to be interpreted cautiously before being ascribed to environmental factors affecting survival from hatching to juvenile stages. An increased understanding of which life stages of PSC are subject to density dependence can refine projections of how these species respond to harvest and other control measures.

Original languageEnglish (US)
Pages (from-to)112-125
Number of pages14
JournalNorth American Journal of Fisheries Management
Issue number1
StatePublished - Feb 2023

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology
  • Management, Monitoring, Policy and Law


Dive into the research topics of 'Spatiotemporal Variation in the Magnitude of Reproduction by Invasive, Pelagically Spawning Carps in the Illinois Waterway'. Together they form a unique fingerprint.

Cite this