Open AccessThe "Knothead" Carp of the Illinois River
Author(s) -
David H. Thompson
Publication year - 1928
Publication title -
illinois natural history survey bulletin/bulletin - illinois natural history survey
Language(s) - English
Resource type - Journals
eISSN - 2644-0687
pISSN - 0073-4918
DOI - 10.21900/j.inhs.v17.287
Subject(s) - carp , degree (music) , animal life , fish <actinopterygii> , fishery , biology , environmental science , geography , zoology , physics , acoustics
The plant and animal life of the middle Illinois River changed fundamentally during and immediately following large increases in the load ofpollution in the years 1916-1918. One of the changes was a markedalteration in the growth form of the carp. While this alteration variedwidely in degree, it was generally obvious in most of the carp and wasreadily recognized by the fishermen. This change has been found to resolveitself into two general outstanding differences: retardation of therate of growth throughout the life of the carp; and marked anatomicalabnormalities, especially of the bones. A number of methods have beenemployed to find out what factors are responsible for these structuraland functional changes.