Effects of six-hour suspended sediment treatments on white sucker (catostomus commersoni) and smallmouth bass (micropterus dolomieu) in an artificial stream

To examine effects of short-term exposure to two types of sediment on health of warmwater fishes, a controlled experiment was conducted with Micropterus dolomieu and Catostomus commersoni. Fishes were stocked into net pens at upstream and downstream ends of an artificial stream. Following an acclimation period of five to six days, discharge was increased throughout the stream to bankfull levels, and fishes in downstream pens (only) were exposed to sediment concentrations of 200 mg/L of fine sand or 500 mg/L of agricultural soil for six hours in two independent trials. Fishes were then immediately assigned a health assessment index value based on conditions of internal and external organs. There were no significant effects on health assessment indices for either species from the experimental treatments, although the indices may have been more sensitive if fish were afforded a post-treatment latent period to allow stress-induced changes to manifest. Our data agree with existing models that describe effects of smaller sediment particles on warmwater fishes and help address the lack of information on effects of larger, coarser suspended sediment.