Population Structure and Habitat Use of Macrhybopsis Chubs in the Missouri River Basin

Little is known about the population structure and habitat use of Macrhybopsis chubs in the Missouri River Basin (MRB). Chubs are characteristic of large Great Plains Rivers and serve as important indicators for the health of ecosystems. Human modifications to the river system have changed population structure and habitat use for Macrhybopsis chubs and as a result their natural resources are low and the genetic diversity is relatively poor, resulting in significant population declines in two Macrhybopsis species, the sturgeon chub and the sicklefin chub. Diet analysis revealed all species of the genus are insectivore drift feeders. Environmental analysis determined that shoal chubs preferred relatively shallow rivers with moderate currents and pebble substrate; whereas sicklefin and sturgeon chubs preferred stronger currents and sand substrate and silver chubs preferred deeper waters with stronger currents. Genotyping by sequencing is currently underway to identify important population molecular markers for the shoal chub, Macrhybopsis hyostoma and to determine the extent of gene flow amongst populations to determine if human modifications to the river have had significant impacts on the shoal chub’s genetic resources and distribution.