Factors influencing stream fish recovery following a large-scale disturbance

We examined fish distribution and abundance in erosional habitat units in South Fork Roanoke River, Virginia, following a fish kill by using a reachwide sampling approach for 3 species and a representative-reach sampling approach for 10 species. Qualitative (presence-absence)and quantitative (relative abundance) estimates of distribution and abundance provided consistent measures of fish recovery for 2 of 3 species at the reachwide scale and 8 of 10 species at the representative-reach scale. Combining results across scales and estimator types showed that distributions and abundances of 5 of 11 species in the reach affected by the kill were similar to those observed in unaffected upstream and downstream reaches 8-11 months following the perturbation. Differences in distribution and abundance between the affected reach and unaffected reaches indicate that 4 of 11 species had not fully recovered during the same time period; results were equivocal for 2 other species. We attribute differences in recovery rates between these two groups to differences in parental investment in offspring. Species exhibiting rapid recovery either engage in extensive spawning site preparation or guard the spawning site following egg deposition and fertilization; species that had not recovered in the year following the kill show limited spawning site preparation and do not guard the spawning site.