Invasion
Invasion Description
1st Record: upstream of Sacramento (Sutter County)/CA/Feather River mouth, Sacramento River (2000, USGS Nonindigenous Aquatic Species Program 2007)
Geographic Extent
Knights/Landing/CA/Sacramento River (2003, Brown and Hieb 2014); Yolo bypass/CA/Sacramento River (2002, USGS Nonindigenous Aquatic Species Program 2007; Hieb 2007); Wards Landing (Colusa County)/CA/Sacramento River (2005, Hieb 2007); Merced County/CA/Mud Slough, San Joaquin River (2005, Hieb 2007); CA/Suisun, Grizzly, and Honker Bays to Carquinez Strait, and infrequently in San Pablo Bay (2005, Hieb 2007; Brown and Hieb 2014); CA/Suisun Marsh (2001, Brown and Hieb 2014; Young et al. 2017); CA/Lindsey Slough, Sacramento River (oung et al. 2017)
Vectors
| Level | Vector |
|---|---|
| Alternate | Ballast Water |
| Alternate | Fisheries Accidental (not Oyster) |
Regional Impacts
| Ecological Impact | Competition | |
| In fresh-oligohaline parts of the Delta, it has become the dominant shrimp, largely replacing Palaemon macrodactylus, the Oriental Shrimp (Hieb 2007). 'Since both P. modestus and P. macrodactylus rear in shallow areas with vegetation or other structure, the reduced catch of P. macrodactylus in the upstream portion of its distribution may have resulted from competitive interactions with or predation by P. modestus.' (Hieb 2007). | ||
| Ecological Impact | Food/Prey | |
| Decapod shrimp, mostly P. modestus, were a major food item in the stomachs of juvenile Striped Bass (Morone saxatilis), next in frequency after amphipods (Nobriga and Feyrer 2008). | ||