Assessing native fish restoration potential in Catoctin Mountain Park

Science Center Objects

Native species conservation is a fundamental purpose of National Parks. Catoctin Mountain Park (CATO) in Maryland supports a prized trout fishery and a healthy community of native fishes, with one exception: native Blue Ridge Sculpin (Cottus caeruleomentum) appear to have been extirpated from Big Hunting Creek above Cunningham Falls. Infection by a fungal-like protist Dermocystidium is hypothesized to have contributed to the extirpation, and such infections have been linked to fish population declines elsewhere. However, warming stream temperatures in the study area also may be an underlying cause. The purpose of this research project is to understand why this native species was extirpated and whether reintroduction is feasible.

We have high confidence that Blue Ridge Sculpin truly have been extirpated from the study area (i.e., Big Hunting Creek above Cunningham Falls). Fish surveys in 2008 confirmed the species was present, and subsequent surveys by the US Geological Survey (USGS) and Maryland Department of Natural Resources (MDNR) did not detect the target species despite intensive sampling from repeated surveys. Moreover, the high abundance of Blue Ridge Sculpin in nearby Owens Creek and the effect of Cunningham Falls as a fish passage barrier also suggest that sculpin have been extirpated from the study area.

Sculpin reintroduction may be particularly important for Brook Trout (Salvelinus fontinalis) conservation because sculpin are prey for large stream-dwelling trout, and additional management actions are currently underway to enhance the population of Brook Trout in the study area (i.e., manual removal of Brown Trout). Sculpin have additional value for stream bioassessment, and they constitute a large component of total fish abundance in nearby Owens Creek, suggesting their loss from Big Hunting Creek may substantially alter stream ecosystem structure and function. The proposed research therefore would provide fundamental support for native fish management and conservation in CATO.

The overarching goal of this research project is to understand why Blue Ridge Sculpin were extirpated and whether reintroduction is feasible. Specific objectives are to:

  1. Quantify stream temperature and trout abundance in the study area;
  2. Experimentally evaluate thermal habitat selection thresholds in Blue Ridge Sculpin and Checkered Sculpin; and
  3. Assess sculpin susceptibility to Dermocystidium infection in candidate reintroduction sites
Blue Ridge Sculpin

Blue Ridge Sculpin from Wikimedia Commons

(Public domain.)