Shelter availability averaged 71% across all sampled occasions (67% modified boot closed, 69% modified boot open, 77% modified hydrodynamic). We deployed 180 shelters of the three designs ( n = 60 each) across six stream reaches in western North Carolina, measured habitat variables at installation points, and monitored shelters for sediment blockage, dislodgement, and hellbender occupancy. We compared three shelter designs (modified boot design with an open bottom, modified boot design with a closed bottom, and a modified hydrodynamic design) to estimate their probability of availability (remaining in place and not obstructed by sediment) to hellbenders during variable stream conditions. Although several artificial shelter designs are currently in use throughout the hellbender range, no previous study has compared different designs in the field. Hellbender declines are likely due to a loss of cover and breeding habitat, therefore artificial shelters have been designed for hellbenders to supplement breeding habitat and monitor reproductive success. The hellbender ( Cryptobranchus alleganiensis) is a fully aquatic giant salamander experiencing population declines throughout the eastern United States.
