Effects of Rosyside Dace (Clinostomus funduloides) on Microhabitat Use of Rainbow Trout (Oncorhynchus mykiss)

We experimentally examined the effects of competition for space between rainbow trout (Oncorhynchus mykiss) and rosyside dace (Clinostomus funduloides) in an artificial stream. These species generally do not exhibit statistically significant differences in microhabitat use in Coweeta Creek, North Carolina, USA. Two competition (trout and dace) and two control (trout only) trials were conducted during spring and summer. Microhabitat use data indicated that the presence of dace did not produce microhabitat shifts in trout. Most behavioral changes could be attributed to acclimation effects or intraspecific competition. Based on field and laboratory results, it does not appear that interspecific competition with dace strongly affects the use of spatial resources in rainbow trout.