Studies on the Life History of the Blunt-Nosed Minnow

Abstract

A collection of 369 specimens of Hyborhynchus notatus from Champaign County, Illinois, was subjected to statistical study and the sex and ages of the various groups were determined. Individuals under 4.5 cm. were under one yr. Males are regularly larger than [female][female] of the same age. Median for [male][male] over one yr., 7 cm., for [female][female] 5 cm. The largest [male][male] which are maximum size encountered in the County, were 7.9 cm. long and nearly 3 yrs. old. The largest [female][female] were 5.7 cm. long and almost 2 yrs. old. It seems probable that the [male] of H. notatus becomes sexually mature after his 3rd winter and dies following a single breeding season. The [female][female] becomes sexually mature at 2 yrs. of age and seem to survive but a single breeding season.