Blue Ridge Sculpin (BRS) populations in Michaux State Forest in south-central Pennsylvania were greatly diminished by acid precipitation from the 1950s through the early 2000s. Rainfall has since returned to near-normal pH and local streams are gradually recovering. Because of their small home range of as little as (Hill and Grossman 1987), we hypothesize that sculpin populations will be especially slow to rebound. This study will estimate how long it will take for the BRS population to reinvade the full extent of their native range in the Mountain Creek drainage of Michaux State Forest, as well as identify conservation strategies that will accelerate their recovery.
We sampled 34 50-m stream reaches in 19 streams using single-pass electrofishing in summer 2024. Data dating back to 2014 was used to track changes in population density. This study will use GIS to model projected sculpin population densities under the conditions described by the Michaux State Forest Resource Management Plan (MSFRMP).
BRS population density has been increasing exponentially in downstream Mountain Creek and downstream Tom’s Run, and was most recently estimated to be 0.11 and 0.41 sculpin per m2 at each site, respectively. Additionally, we found BRS at two sites upstream in Mountain Creek for the first time, with population densities estimated at 0.12 and 0.0042 sculpin per m2.
Using data from studies on related species of sculpin, we will predict how long the BRS population in Michaux State Forest will take to fully recover. One study found that Mottled Sculpin overwhelmingly prefer woody debris habitat (Deboer et al. 2015), and the MSFRMP specifies evaluating the need for large woody debris in aquatic habitats (PA DCNR 2020). The installation of woody debris in these streams will increase the amount of preferred sculpin habitat, which should support upstream movements and accelerate range reclamation.