Research Publications: UM-SG-RS-2007-05


Variation in the ability of Didemnum sp to invade established communities.




Osman, RW; Whitlatch, RB


Journal of Experimental Marine Biology and Ecology
342 ( 1 ) : 40 - 53




Over the past 30 years southern New England, USA has been invaded by several species of ascidians, including Botrylloides violaceus, Diplosoma listerianum, Styela clava, and Ascidiella aspersa. These species have become dominate in coastal embayments and marinas but are usually absent from more open water coastal areas. A colonial ascidian, Didemnum sp. has invaded southern New England during the past 10 years and we first observed this species in eastern Long Island Sound in 2000. It has become the dominant at several field sites while remaining in low abundance at others. We conducted an experiment at two places, a protected marina and an open coast site, to examine its ability to compete with the established fouling community. Small colonies of Didemnum were transplanted onto panels with communities that varied in age from one to four weeks old and these treatments along with controls with only Didemnum were exposed at both sites. In most treatments Didemnum became a dominant species in the communities at both sites but it reached higher abundances at the open coast site. Potential causes of the observed differences are predation on other species of ascidians at the open coast site reducing recruitment of these species and competition, lower tolerance for elevated temperatures at the marina site, or other environmental parameters that might affect growth rates.

Related Research Project(s) Funded by Maryland Sea Grant:

Maryland Sea Grant Topic(s):

'Related Research Project(s)' link to details about research projects funded by Maryland Sea Grant that led to this publication. These details may include other impacts and accomplishments resulting from the research.

'Maryland Sea Grant Topic(s)' links to related pages on the Maryland Sea Grant website.

The Blue Crab: Callinectes Sapidus

An essential resource for researchers, students, and managers.  Get your copy today!

pile of cooked crabs

5825 University Research Court, Suite 1350 | College Park, MD 20740 | Phone: (301) 405-7500 | Fax: (301) 314-5780 | Contact Us

  • Twitter
  • Facebook
  • YouTube
  • Flickr
  • RSS