3.6 Freshwater Mussels
3.6.6 Threats and Problems Invasive and nonnative species can create competitive pressures on food resources. Further, their burrowing activity can uproot native mussels in sandy sediments (Vaughn and Hakenkamp 2001; Bogan et al. 2011) . In 2007, the frst location in the state of the nonna- tive Lilliput was discovered at Falls Lake in Wake County and was confrmed through DNA analysis (Bogan et al. 2011) . Asian Clam can be found throughout the state, often in such large quantities that they decrease
Tar River Spinymussel (Melissa McGaw, NCWRC)
available oxygen (Belanger et al. 1990; Lef et al. 1990; Bucci 2007) and create high levels of ammonia in streams that can negatively afect native mussels.
Extinction of North American unionoid bivalves can be traced to impoundment and inun- dation of rife habitat in major river basins of the central and eastern United States. Dams are a barrier to host fsh and the loss of obligate hosts, coupled with increased siltation, and various types of industrial and domestic pollution have resulted in the rapid decline in the unionoid bivalve fauna in North America (Bogan 1993) . Hypolimnion water discharged from behind a dam will be colder and have less oxygen than downstream receiving waters (Neves and Angermeier 1990) . Participation in the Federal Energy Regulatory Commission (FERC) relicensing process will facilitate negotiation of more natural fow regimes in regulated rivers and help identify opportunities to mitigate negative impacts from hydropower development. Contaminants and water pollution are a signifcant threat to all aquatic species, especially mussels. Point source discharges from municipal wastewater that contains monochlora- mine and unionized ammonia compounds are acutely toxic to freshwater mussels and may be responsible for glochidial mortality that results in local extirpation of mussels (Goudreau et al. 1993; Ganglof et al. 2009) . However, given the transient nature of fowing systems (e.g., a water continuum) and the potential for dilution at any point along the system, it is especially difcult to detect not only origin points but also concentration levels in the water column (Fleming et al. 1995) . A die-of event afecting Tar River Spinymussel populations was detected in the Swift Creek watershed (Nash County) as it occurred and was attributed to anticholin- esterase poisoning related to organophosphorus and carbamate pesticides used in agricul- tural applications (Hill and Fleming 1982; Fleming et al. 1995) . Since the publication of Kolpin et al. (2002) on the extent and diversity of chemicals present in the nation’s waters, there has been increased concern about the biological relevance of the mix of chemicals to which mussels and other aquatic organisms are exposed, including
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2015 NC Wildlife Action Plan
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