Movement patterns of southern redbelly dace, Chrosomus erythrogaster, in a headwater reach of an Ozark stream

Previous research on fish movement has focused primarily on recreationally important fishes in perennial streams; however, fewer studies have examined movement patterns of small-bodied fishes in intermittent streams where abiotic and biotic conditions can be extreme compared with perennial systems. Using markrecapture, we examined movement patterns of southern redbelly dace, Chrosomus erythrogaster, in an intermittent Ozark stream having both permanently connected and temporally isolated sections. Juvenile (6088%) and adult (5583%) residency rates were not significantly different for any markrecapture sample, and movement was primarily within a section for both groups. Ontogenetic differences were detected for kurtosis, distance moved and population spread, with adults exhibiting greater variability in movement, moving more often and further. When considering only adults, there was a significantly higher number of individuals that exhibited intermovement from isolated sections compared with connected sections. In addition, a higher proportion of adults exhibiting intermovement moved to connected stream sections in May and July compared to January and March. Dace exhibited upstream bias in July, with 76% of emigrates moving to an upstream connected section. Although there were no statistically significant associations between the proportion of intermovers from connected and isolated sections and measured water quality and habitat variables, noteworthy trends were observed, and these trends were always stronger for connected sections. Understanding the factors that influence population dynamics in headwater streams is important for the survival and persistence of stream fish populations, especially considering the anticipated expansion of intermittent headwater streams as a result of future climatic changes.