Asian carps in the mid-continent great rivers

Great river research has been ongoing by multiple federal, state, and multi-state organizations in the Upper Mississippi, Missouri, and Ohio rivers.  Concurrently, expansion of Asian carps in the central US presents a huge challenge to resource managers. Together, these programs shed light upon our understanding of the various effects of non-native species.  Invasive bighead Hypophthalmichthys nobilis and silver carp H. molitrix catches showed increasing populations in all of these rivers, with exponential increases in some reaches.  Data from the Illinois River has documented reduced body condition in native planktivores (gizzard shad Dorosoma cepedianum and bigmouth buffalo Ictiobus cyprinellus) since the Asian carps invasion.  A recent population estimate for silver carp highlights the concern regarding these fish, with an estimated 4,100 sub- and adult fish per river mile in La Grange Reach, Illinois River.  Data throughout the rivers confirms a strong correlation among spawning success and hydrology.  Further analysis of relative catch rates will allow for temporal and spatial comparisons.  Wide ranging monitoring efforts and comparisons across geographical and/or political boundaries are essential for inter-jurisdictional fisheries management.