Movements of selected minnows between the lower Yellowstone River and its tributaries

Reduced population connectivity has been implicated as a cause of decreased distributions and abundances of many Great Plains fishes. However, scant empirical evidence quantifying movement and relating the contribution of spatial linkages to population abundances and resilience exists. We used otolith microchemistry analysis to characterize the movements of western silvery minnows (Hybognathus argyritis Girard, 1856), flathead chubs (Platygobio gracilis (Richardson, 1836)), and sand shiners (Notropis stramineus (Cope, 1865)) between the Yellowstone River and its tributaries. Sixty-nine percent of western silvery minnows, 65% of flathead chubs, and 42% of sand shiners moved between the Yellowstone River and tributaries. Mean total number of interchanges was highest among western silvery minnows (4.8 interchanges/mover), intermediate among flathead chubs (4.3 interchanges/mover), and lowest among sand shiners (1.4 interchanges/mover; P < 0.01). Natal movements were rare, but juvenile movements were common and frequent among all three species. Movements between main-stem and tributary habitats are probably prominent facets of the life cycles of other Great Plains minnows. Therefore, connectivity among such habitats should be a high conservation priority to enhance the long-term viability of such fishes.