Invasion

Invasion Description

1st Record: Conowingo Dam [in Conowingo Village]/MD/Susquehanna River (2008, USGS Nonindigenous Aquatic Species Program 2008), 1 specimen in power plant intake). The scattered collections of small numbers of settled mussels and veligers inidcate a small, but established population (Klauda and Ashton 2013; Klauda and Ashton 2015).

Geographic Extent

Peach Bottom Atomic Power Station/PA/Susquehanna River (nontidal, ~15 km upstream of Conowingo, 2009-2013, 47 to 5,000 veligers collected per year, but only 2-4 settled mussels, Klauda and Ashton 2013); Conowingo Dam [in Conowingo Village]/MD/Susquehanna River (11/20/2008, USGS Nonindigenous Aquatic Species Program 2008, 1 specimen in power plant intake); (nontidal, Glen Cove Marina/MD/Conowingo Pond (single mussel on boat); City of Baltimore water intake, upstream of Conowingo Dam/MD/Susquehanna River (6/11/13, Klauda and Ashton 2013), zebra mussels attaced to intake); Harford County water intake, upstream of Conowingo Dam (5/20/12, veligers found in water samples, Klauda and Ashton 2013); Spencer and Roberts Islands, below Conowingo Dam/MD/Susquehanna River (7/6/2010, Maryland Department of Natural Resources 2010, http://dnr.maryland.gov/dnrnews/pressrelease2010/071510c.asp, 9 live, 2 dead mussels. More were found here in 2012, Klauda and Ashton 2013); near Betterton/MD/Sassafras River, near mouth of Turner Creek (10/17/2011, USGS Nonondigenous Aquatic Species Program 2011, 1 mussel, dead, but it was still attached to a jet ski mooring).; buoys off Havre de Grace/MD/Susquehanna River-Chesapeake Bay (12/3/12, http://news.maryland.gov/dnr/2012/12/17/more-zebra-mussels-found-in-upper-chesapeake-bay/; Klauda and Ashton 2013, about 20 live mussels found; Klauda and Ashton 2015); Havre de Grace/MD/Susquehanna Flats (Ashton and Klauda 2014, Ashton and Kaluda 2015, 100s to 1000s on floats and lines); MD/Bush, Gunpowder, Middle River estuaries (7-8/205, Wheeler 2015, settling on crab gear and submerged vegetation)