Graduate Program
Biological Sciences
Degree Name
Master of Science (MS)
Semester of Degree Completion
2012
Thesis Director
Robert Colombo
Thesis Committee Member
Eric Bollinger
Thesis Committee Member
Dave Wahl
Abstract
The silver carp, Hypophthalmichthys molitrix, is an invasive species that has received increased attention due to the proximity of the population in the Illinois River to the economically important Great Lakes and the species ability to dominate the aquatic biomass of an ecosystem. We sought to assess the population demographics of silver carp on two different river ecosystems, the Illinois River and Wabash River. The Illinois River is channelized and dammed for commercial barges, whereas the Wabash River is the longest free flowing river east of the Mississippi River and is still connected to its natural flood plain. Silver carp were captured using DC electrofishing, weighed (g), measured (mm), and a postcleithrum bone was removed for age estimation. The relative density (fish/hour) of silver carp in the Illinois River (56.25 ± 15.58) was over three times that of the Wabash River (16.9 ± 2.47). Average length (mm) was higher in the Wabash River (563.2 ± 11.85) than in the Illinois River (517.14 ± 3.25). In both rivers, carp exhibit quick growth reaching lengths over 300 mm in the first year. The total annual mortatity for the Illinois was higher than on the Wabash, 0.587 and 0.317 respectively. Furthermore, the hybridization rate with bighead carp, Hypophthalmichthys nobilis, was higher in the Illinois (72.9%) than the Wabash (24.5%). Although silver carp in the Wabash River showed fast growth and low adult mortality, the density was several times lower possibly due to increased resilience of the more pristine ecosystem.
Recommended Citation
Stuck, Jason G., "Comparison of silver carp population demographics in an impounded and a free flowing river" (2012). Masters Theses. 1046.
https://thekeep.eiu.edu/theses/1046
