INFLUENCE OF DISPERSAL, NATAL ENVIRONMENT, AND VARIANCE IN REPRODUCTIVE SUCCESS ON THE GENETIC RELATIONSHIPS WITHIN A POPULATION OF FRESHWATER FISH BY

ii There must be genetic change both through time and over space for organisms to adapt to local environmental conditions. Gene flow inhibits genetic differences from accumulating over space, while the magnitude of the variance in reproductive success among adults sets the upper limit on the rate of change through time. The chapters included in this dissertation present a series of investigations into the factors and processes that influenced the magnitude of gene flow among the smallmouth bass that inhabited a small-scale connected river-lake system. In Chapter Two, I determined the distance that smallmouth bass had dispersed from their natal sites during the first year of life and where adult males nested relative to the location of their own natal sites. More than three-quarters of the offspring were captured within 1 km of their natal sites. Nearly a third of the males that hatched in the river habitat were found to have spawned within the same pool in which they hatched and 12 % of the males that hatched in the lake habitat nested within 150 m of their natal sites. The fact that many offspring reproduced in close proximity to their natal sites suggests that there would be restricted gene flow over space and strong potential for spatia