No Carping, Illinois Fishes for Answers

Illinois (US) has become 'ground zero' in the fight against an invasion of Asian carp. These fish have adapted so successfully to conditions here that the greatest wild densities of bighead and silver carp in the world are now found in the lower three reaches of the Illinois River. The potential environmental and economic implications ofsuch an invasion could be devastating. To estimate the density, size distribution and biomass of Asian carp in the five lower reaches of the Illinois River, Southern Illinois University (SIU) researchers Jim Garvey and David Glover are conducting hydroacoustic surveys using a BioSonics DT-X split-beam echosounder.

To date, they have completed transects along more than 270 total river miles. Garvey and Glover are developing species-specific relationships between acoustic target strength and body size, which will facilitate in processing acoustic data to determine species composition and size distribution. As Glover explained, the initial results from the DT-X are very encouraging; "The spatial distribution we are seeing confirms everything in the literature. We have been amazed at the results from the hydroacoustic data." The SIU team joins Illinois Natural History Survey, USGS, and many other state and provincial agencies in using BioSonics DT-X technology for fisheries research in and around the Great Lakes region.

 

The information will be incorporated into GIS to create maps showing biomass and distribution of Asian carp overlaid onto depth contours and substrate classifications. These data will help to identify hotspots for focusing commercial fishing efforts.

 

Data from the hydroacoustic surveys will be studied along with data from netting, tagging and tracking, and otolith studies to better understand the immigration and emigration patterns of Asian carp. Other researchers hope to use the data to develop a model that can be used to predict how much fishing effort would be required to keep Asian carp abundances low in perpetuity. Ultimately, it is hoped that this effort will improve conditions of the Illinois River and prevent range expansions of Asian carp to Lake Michigan and other uninvaded systems.