Within Watershed Population Structure of an Amphidromous Hawaiian Goby

The influence of habitat fragmentation on population dynamics within watersheds is not well understood, particularly for species known to disperse great distances. Effective conservation management, however, relies in part on an understanding of the role connectivity plays in maintaining viable populations over time and space. This study examined within and between watershed genetic variation and demographic structure of Awaous stamineus in three watersheds along the Hamakua Coast on the island of Hawaii (Hawaii, USA) to evaluate the effects of spatial structure on population persistence. Macrosatellite analyses indicated no spatial structure over the range studied, and was consistent with high gene flow within and between watersheds. Demographic estimates from mark-recapture suggested differences in apparent recruitment between watersheds that may be related to the presence of invasive Poeciliid fish, or other watershed-specific environmental conditions. Further studies are needed to specifically test the role of in-stream barriers and altered flow on recruitment dynamics and gene flow in amphidromous species. Results from this study imply that restoration efforts at the watershed scale could promote recovery of native populations.