Invasion

Invasion Description

1st Record: Portland/OR/Willamette River (1931, USNM 42720, US National Museum of Natural History 2011, Schmitt 1939). It has been collected in ponds and lakes in the Columbia River watershed (USGS Nonindigenous Species Program 2011), but we know of no further records in the estuary.

Geographic Extent

Portland/OR/Willamette River (1931, USNM 42720, US National Museum of Natural History 2011, Schmitt 1939)