Gravel chub silt and debris. They are more often found in areas with limited macrophytes and larger root aquatic plants, algae and moss. Because of their need of a specialized clean habitats, the gravel chub is especially vulnerable to various forms of pollution, especially from agriculture practices that create erosion and excessive silt. In past sampling surveys the gravel chub had been found as far north in the Upper Iowa River as Le Roy, Minnesota, but because of excessive amounts of sewage, pesticides and sedimentation of rocks and sand, this is no longer the case. The presence of gravel chubs in a
Gravel chub May and continuing into June. Adult gravel chubs have been spotted spawning by gathering on gravel bars in soft currents created by a rise in the waterline after hard rains. The gravel chub is considered a threatened species in many areas mostly due to the fact that it has a highly specific, clean habitat need. As of 1988 it was considered endangered in Kansas, under legal protection in Indiana and Wisconsin and considered a special concern in Kentucky, Minnesota and New York. Gravel chubs need constant mild currents with silt free riffles. Agriculture run-off is the biggest threat to this