Date of Graduation

2005

Document Type

Thesis

Degree Type

MS

Committee Chair

Kyle J. Hartman

Abstract

Recent surveys have indicated that populations of fishes and crayfish are small in the Stony River, Grant Co., WV. The Stony River is influenced by thermal enrichment and acid mine drainage (AMD) within a 13 km stream reach, downstream of Mt. Storm Lake. In an attempt to determine the influence of each anthropogenic disturbance on these affected taxa, studies of their distribution and survival were undertaken. A crayfish trapping survey was conducted along a gradient of thermal and AMD influences in the Stony River system. Cambarus bartonii was the only species captured, although two subspecies of C. bartonii living in WV were present. Crayfish capture rates were significantly higher at a site below the confluence with a healthy tributary than at sites influenced by thermal enrichment and AMD. This tributary may provide refuge from anthropogenic disturbances, and a source of crayfish for recolonizaiton of the Stony River. In situ bioassays were undertaken with the crayfish C. bartonii in the areas influenced by anthropogenic disturbances to determine potential mortality of adult crayfish during the period of highest potential stress associated with those influences (late summer). Mortality increased with extended elevated temperatures, reaching 88% at one site with four days of elevated temperatures >30°C. Temperatures resulting in significant mortality were slightly lower than previously determined for this species in laboratory studies. Parameters related to AMD conditions did not correlate with crayfish survival in 28 day bioassays. A laboratory temperature study was undertaken to confirm upper lethal temperatures

for this population of C. bartonii. Upper thermal limits were found to be similar to previous laboratory studies, and laboratory temperatures (mean = 31.8°C) were similar to those that correlated to a period of high temperatures (~4 days) that coincided with high mortality in field bioassays (mean = 31.6°C). In a set of separate studies, larval fish were surveyed along the Stony River gradient from late March through June of 2004 using light traps. Fish were found to be reproducing in the Stony River, with 670 larvae captured over the sampling period. White sucker (Catostomus commersoni), smallmouth bass (Micropterus dolomieu), creek chub (Semotilus atromaculatus) and central stoneroller (Campostoma anomalum) were the only species of fish captured. White sucker larvae comprised 91% of all larvae captured. White sucker larvae appeared in trapping samples six weeks earlier in the thermally influenced system than in a reference tributary. Additionally, larval capture rates were significantly lower at sites in AMD mixing zones than sites directly above the mixing zone. Fathead minnow (Pimephales promelas) larvae were used for in situ bioassays along the Stony River continuum from mid-May to mid-June. Complete mortality of fathead minnow larvae occurred in an AMD mixing zone. Timing of mortality coincided with pH depression in an AMD influenced tributary directly upstream of the bioassay site. Other sites showed no clear pattern in fathead minnow larvae survival, and neither temperature nor AMD parameters were statistically correlated with larval survival. Study results suggest that crayfish inhabitation of the anthropogenically influenced areas of the Stony River may be limited by elevated summer temperatures, and that AMD conditions are not lethal to adult, intermolt C. bartonii. Larval fish studies suggest that reproduction timing is influenced by the elevated thermal regime, and that AMD mixing zones may be areas of substantial larval fish mortality in the Stony River.

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