The sex ratio of river carpsuckers collected from the Des Moines River differed significantly from 1:1, females being most abundant. Spawning had already begun in early June and some fish were found ripe as late as August. No carpsuckers younger than age IV were found mature. All ripening carpsucker ovaries contained a group of eggs that seemed to be degenerating. It is not certain if carpsuckers spawn more than once in a season.
Proceedings of the Iowa Academy of Science
©1965 Iowa Academy of Science, Inc.
Behmer, David J.
"Spawning Periodicity of the River Carpsucker, Carpiodes carpio,"
Proceedings of the Iowa Academy of Science, 72(1), 253-262.
Available at: https://scholarworks.uni.edu/pias/vol72/iss1/39