Fish species composition in two second-order headwater streams in the North Central Appalachians ecoregion

Fish species composition was determined for two second-order headwater stre ams within the North Central Appalachians ecoregion in northern Pennsylvani a. The two streams were widely spaced geographically (over 193 km apart) an d occurred in different drainage systems. Streams were sampled in the sprin g and fall over two years (1996-98) yielding similar fish assemblages. A to tal of five species was collected. Mottled sculpin (Cottus bairdi), slimy s culpin (Cottus cognatus), brook trout (Salvelinus fontinalis), and brown tr out (Salmo trutta) were the dominant adult fishes. Two creek chubs (Semotil us atromaculatus) were also collected. No significant differences were foun d in sculpin weight, sculpin length, salmonid length, or brook trout length between streams. Paired t-tests detected eight significant seasonal differ ences within sites. Brook trout and mottled sculpin lengths were significan tly greater in fall versus spring, while the reverse was found with slimy s culpins. Catches per unit effort were similar between the two streams, yiel ding 8.46 and 8.07 fish per minute of electrofishing. Both streams were ver y similar in faunal assemblages attributed to small, coldwater, high qualit y headwater streams in other regions.