Publication Detail

Competition Among Invading Ascidians and a Native Mussel

Rubi Rajbanshi, Judith A Pederson
3 pp.
MITSG 07-03J
$5.50 DOM / $7.50 INT

Sustained multiple stresses can determine the composition and species dominance of epibenthic communities on hard substrata (Stachowicz et al., 2002a) especially when space is a major limiting resource (Dayton, 1971; Paine, 1974). Stresses include species removal and creation of open space allowing native and non-native species to recruit into these spaces (Carlton, 1996; Vitousek et al., 1996; Simberloff and Von Holle, 1999). The blue mussel Mytilus edulis is often found in close association with the non-native ascidians Asci-diella aspersa, Ciona intestinalis, and Botrylloides violaceous in Boston Harbor, Massachusetts, USA, and this study focused on interaction for space between them. Previous studies on fouling communities indicate that either a competitive hierarchy exists between species, or species tend to complement each other using space (Buss and Jackson, 1979). Field experiments were conducted at Rowes Wharf, Boston Harbor. Twelve 10.2 cm by 10.2 cm PVC plates were submerged from docks to a depth of 3 m below the surface throughout the year and were examined for the presence of tunicates and mussels in the summer of 2004. Organism percent cover on the plates was estimated using 25 random points on clear plastic sheets as well as visual estimates of percent cover. Organism lengths were measured using calipers. All other species excluding the tunicates were scraped from the seven plates. Fiberglass netting was secured around each plate in baglike formations to deter predators.

type: Journal, book, proceeding reprints

Parent Project

Project No.: 2003-A-5
Title: MIT Sea Grant Center for Coastal Resources