Delta Invasive Species

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Invasive Animal Species in the Delta

Click the caption of each photo for more information about the species.

Two golden mussels above a ruler. Photo by Jeb Bjerke, California Department of Fish and Wildlife.
Golden mussel – Limnoperna fortunei (Photo by CDFW)
Many tan-colored New Zealand mudsnails (Potamopyrgus antipodarum) shown with a dime for size reference. Photo by U.S. Geological Survey.
New Zealand mudsnails – Potamopyrgus antipodarum (Photo by U.S. Geological Survey)
A northern watersnake (Nerodia sipedon) with brown and tan stripes in the grass next to a rock. Photo by Patrick Coin.
Northern watersnake – Nerodia sipedon (Photo by Patrick Coin)
A nutria (Myocastor coypus) animal with brown fur, white whiskers and orange teeth. Photo by CDFW.
Nutria – Myocastor coypus (Photo by CDFW)
Five dark brown/tan-striped and five light brown/tan-striped Quagga Mussels (Dreissena rostriformis bugensis) shown next to a dime in a person's hand for size reference. Photo by CDFW.
Quagga Mussels – Dreissena rostriformis bugensis (Photo by CDFW)
A southern watersnake (Nerodia fasciata) with tan, brown, and red-striped skin in the grass. Photo by CDFW.
Southern watersnake – Nerodia fasciata (Photo by CDFW)
A Zebra mussel (Dreissena polymorpha) with brown, tan, and cream-colored stripes.
Zebra mussel – Dreissena polymorpha

Invasive Plant Species in the Delta

Click the caption of each photo for more information about the species.

The white flower and green leaves of an alligatorweed (Alternathera philoxeroides) plant. Photo by National Plant Data Center, Baton Rouge, LA.
Alligatorweed – Alternathera philoxeroides (Photo by National Plant Data Center, Baton Rouge, LA)
A section of the Brazilian egeria (Egeria densa) plant. Photo by Lara Gudmundsdottir.
Brazilian egeria – Egeria densa (Photo by Lara Gudmundsdottir)
Brown, fluffy seedheads and green leaves of the nonnative common reed (Phragmites australis subsp. australis) plant. Photo by Erlend Bjortvedt.
Common reed – Phragmites australis subsp. australis (Photo by Erlend Bjortvedt)
Curlyleaf pondweed (Potamogeton crispis) plants in the water. Photo by Christian Fischer.
Curlyleaf pondweed – Potamogeton crispis (Photo by Christian Fischer)
Eurasian watermilfoil (Myriophyllum spicatum) in the water. Photo by Fungus Guy.
Eurasian watermilfoil – Myriophyllum spicatum (Photo by Fungus Guy)
Giant reed (Arundo donax) plants growing in the Sacramento-San Joaquin Delta.
Giant reed – Arundo donax
White flowers and green leaves of the perennial pepperweed (Lepidium latifolium) plant. Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org.
Perennial pepperweed – Lepidium latifolium (Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org)
Purple loosestrife (Lythrum salicaria) plants with purple flowers and green leaves. Photo by Liz West.
Purple loosestrife – Lythrum salicaria (Photo by Liz West)
South American spongeplant (Limnobium laevigatum) in the water. Photo by Cardex.
South American spongeplant –Limnobium laevigatum (Photo by Cardex)
Purple water hyacinth (Eichhornia crassipes) flowers with yellow and blue markings and green leaves growing in the water. Photo by Wouter Hagens.
Water hyacinth – Eichhornia crassipes (Photo by Wouter Hagens)
The flower and leaves of a water primrose plant (Ludwigia spp.). Photo by Bouba.
Water primrose – Ludwigia spp. (Photo by Bouba)

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