Taxonomy Search:

Molgula manhattensis
Image courtesy of Melissa Frey, Royal BC Museum, Canada
Molgula manhattensis
Taxonomic Group: Tunicates
Common name: SEA GRAPES


Molgula manhattensis, also known as the Sea Grape, is a solitary tunicate with a round, globular body shape.  It is native to the East and Gulf Coasts of the United States and has been introduced to Europe, Japan, Australia, Argentina, and the West Coast of North America. On the West Coast, its introduced range spans from Newport Beach, California to British Columbia, Canada. It was first discovered in Tomales Bay, California in 1949 and in San Francisco Bay in the 1950s, where it is now abundant and widespread. It is a common fouling species and was likely transported on ship hulls or through Eastern Oyster (Crassostrea virginica) aquaculture. Molgula manhattensis is known to negatively affect oyster aquaculture, because it fouls oyster stock and oyster cultch (empty shells, used for spat settlement).  Competition with other fouling species has also been observed in several locations including Newport and Alamitos Bay in California.  It is tolerant of a wide range of temperatures, salinities and pollution levels and is found on both natural and artificial substrates.

This is some default tab content, embedded directly inside this space and not via Ajax. It can be shown when no tabs are automatically selected, or associated with a certain tab, in this case, the first tab.


Fofonoff PW, Ruiz GM, Steves B, Simkanin C, & Carlton JT (2018)
National Exotic Marine and Estuarine Species Information System.
Access Date:

Marine Invasions Lab
Smithsonian Environmental Research Center

P.O. Box 28
647 Contees Wharf Road
Edgewater, MD 21037-0028 Tel: 443 482 2200
Fax: 443 482 2380

Databases Overview| Chesapeake Bay | National Database |