Dermocystidium sp. Infection in Blue Ridge Sculpin Captured in Maryland

Abstract

Raised pale cysts were observed on Blue Ridge Sculpin Cottus caeruleomentum during stream fish community surveys in Catoctin Mountain Park, Maryland. When examined histologically, preserved sculpin exhibited multiple cysts containing spherical endospores with a refractile central body characteristic of Dermocystidium spp. Cysts were not observed on the gills or internally. The portion of the watershed in which affected sculpin were observed contained lower than expected numbers of sculpin, raising concerns about the population effects of this infection. A nearby stream lacked sculpin even though they are common in this region, further suggesting the possibility of regional effects. This is the first report of a Dermocystidium infecting any fish species in the eastern United States.

Received October 16, 2015; accepted February 14, 2016 Published online July 25, 2016

Acknowledgments

Funding for this project was provided by the U.S. Geological Survey’s Fisheries, Environments (Chesapeake Bay) and National Resources Protection programs (Ecosystems Mission Area) and Contaminants Biology (Environmental Health Mission Area). We thank John Mullican, Joshua Henesy, and Mark Toms of the Maryland Department of Natural Resources for assistance with fish collections; Kathy Spring and Darlene Bowling, Fish Health Branch, Leetown Science Center, for preparation of the histology samples; and Heather Walsh for development of the primer sets. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the federal government.