Taxonomic name: Chthamalus proteus Dando and Southward, 1980
Common names: Atlantic barnacle (English), Caribbean barnacle (English)
Organism type: crustacean
Chthamalus proteus is a barnacle native to the Caribbean and western Atlantic. It was introduced to the Pacific in 1970s and first reported in Hawaii in 1995. It is now one of the most abundant organism in the upper intertidal harbors and bays throughout the Hawaiian Islands. C. proteus are likely to be spread by ship hull fouling and larvae by ballast water.
Chthamalus proteus is a small light brown or gray white barnacle that grows to about 1cm diameter. Its conical shell is variable in external appearance depending on age, crowding, and degree of weathering. Shell plates may be smooth or ribbed.
coastland, estuarine habitats, marine habitats
Chthamalus ptroteus uses similar habitat types in introduced ranges as in native ranges. It is found in protected bays, lagoons, harbors and embayments, particularly where there are few other intertidal organisms (DeFelice et al. 2001; Zabin 2002). The barnacle inhabits the upper intertidal zone, where it occurs on both natural and man-made surfaces (DeFelice et al. 2001). Rare in open-coast settings, these barnacles appear to tolerate a fairly wide range of water temperatures (from 16°C to 38°C). They are also able to survive in both clear and turbid waters (Zabin 2005). Habitat modifications that increase hard substrata and decrease wave action are likely to facilitate their spread (Zabin 2003). In its native range (Gulf of Mexico and the Caribbean) it does not tolerant low salinity and is found in highest densities in moderate to low energy locations in muddy or murky water. The introduced Hawaiian mangrove Rhizophora mangle is able to facilitate establishment of C. proteus, as its roots provide an ideal habitat for this introduced barnacle (Amanda and Craig 2003).
C. proteus is a serious fouling organism. This species potentially threatens to alter natural substrates through dense colonisation, which could lead to habitat conversion, alter settlement patterns of native species and exclude algal grazers such as opihi (limpets). Competition for space with native invertebrates in the high intertidal zone is also likely to occur (DeFelice et al. 2001). At high densities the barnacle appears to negatively impact the limpet Siphonaria normalis in Hawaii (Zabin 2005).
Native range: Gulf of Mexico, Caribbean Sea and southwestern Atlantic Ocean (Dando and Southward 1980, in Zardus and Hadfield 2005).
Known introduced range: Hawaiian Islands, Midway Atoll and Guam (Southward et al. 1998; DeFelice et al. 1998).
Introduction pathways to new locations
Ship ballast water:
Ship/boat hull fouling: Chthamalus proteus was introduced in the 1970s via ships (Southward et al. 1998). Larvae of this barnacle have survived the journey from the Caribbean to Hawaii in a ballast tank (Godwin 2003).
Local dispersal methods
Boat: Chthamalus proteus is dispersed between neighour islands by water vessels (Zardus and Hadfield 2005).
Natural dispersal (local):
There is no specific management for controlling C. proteus at this moment. It is recommended to step up monitoring programs for C. proteus for preventative purposes (Southward et al. 1998). Physical factors may limit the spread of this barnacle and provide some natural protection from invasion, for example open coastal habitats (Zabin 2003).
This barnacle has a specialised pair of appendages, called cirri, which are used as a scoop net, reaching out into the water to extract food particles. When the cirri are drawn back, food is scraped off into the mouth (DeFelice et al. 2001).
These barnacles are hermaphrodites. Cross-fertilisation occurs in dense populations. In such cases, sperm are deposited directly into the mantle cavity of adjacent individuals via a long tube. Fertilised eggs are brooded in the mantle cavity, and it may be several months before the free-swimming planktonic larvae are released (DeFelice et al. 2001).
There are seven stages for C. proteus, six naupliar stages followed by a cypid. The developmental period is short and varies with temperature and diet. At low food concentration, the higher the temperature, the quicker the larvae develop into cyprids. At 28 C° the earliest cyprids could develop within 10 days. At high food concentration, there temperature does not play a role in development time (Zabin 2005).
Compiled by: IUCN/SSC Invasive Species Specialist Group (ISSG) with support from La Fondation d'entreprise Total
Last Modified: Wednesday, 10 January 2007