First Year Survival and Dispersal of Neosho Smallmouth Bass

We measured first-year survival and dispersal of Neosho Smallmouth Bass Micropterus dolomieu velox in two Ozark streams during summer 2013. Mortality over the first growing season was determined via snorkel surveys beginning at nest dispersal and continuing bi-weekly through early October. Beginning and end of growing season abundance estimates were approximately 17,000 and 600 fish per kilometer in Buffalo Creek and 43,000 and 250 fish per kilometer in Spring Creek. Survival from the time fry dispersed the nest until early October was 3.40% and 0.56%, respectively for the two streams. Dispersal was estimated by recording the number of young found in each channel unit for the duration of the study. As expected, abundance estimates were much greater in the spawning channel unit, particularly pools, during the first several weeks following dispersal from the nest. Abundances increased in runs, backwaters, and slow riffles as fish grew and overall abundances declined over the summer. We observed differential use of low velocity off-channel habitats when discharge increased during particular sampling periods. This study suggests habitats perceived as unimportant to smallmouth bass may be very important to first-year survival during elevated discharge conditions.