Changes in the Status of Native Brook Trout on Laurel Hill, Southwestern Pennsylvania
2018
Argent, David G. | Kimmel, William G. | Gray, Derek
To evaluate the status of native Salvelinus fontinalis (Brook Trout) on Pennsylvania's Laurel Hill, we sampled fish, assessed habitat, and documented water quality from 20 non-randomly selected headwater streams of northwest- and southeast-facing slopes. In late spring and early summer of 2011 and 2014–2016, we sampled fish communities and measured specific conductance (μS/cm), total alkalinity (mg/l as CaCO3), pH, and total dissolved aluminum (2011 and 2016). In addition, in 2015 we determined land-use patterns, riparian canopy, and substrate composition. Mean pH values among the streams recently assessed were significantly higher than historic values; however, all other water-quality parameters were similar. Native Brook Trout were present in all streams, and annual natural reproduction was evident in 90% of streams. Even though fish were present, we observed marked declines in total catch in both 0-age and adult trout; the overall reduction approached 60% when compared with those documented in 1983. We discuss possible causes for the observed declines, including acid deposition, introduction of nonnative/invasive species, water withdrawal, habitat fragmentation/alteration, predation, and climate change.
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