Species composition and geographic distribution of invertebrates in fouling communities along the east coast of the USA: a regional perspective

In recognition of increasing coastal development, warming seas, species invasions, and numerous systematic revisions, we have reviewed the fouling community literature to update the species composition and geographic distributions exhibited by this fauna along the east coast of the USA. We found 1443 records for 317 species. The Bryozoa were the most prevalent phylum in terms of numbers of records and species, but 2 invasive ascidians were the most frequently reported species. Among all species, 9.1% of the fauna have been reported to be invasive. Most species were represented by only 1 to 3 records, suggesting that this fauna has been underrepresented in the literature. The number of species estimated per state peaked in Florida, North Carolina, and Massachusetts, where provincial faunas overlap. Although Cape Cod in Massachusetts and Cape Hatteras in North Carolina represent putative faunal boundaries along the east coast, 63% of the fouling organisms have distributional limits which extend well beyond one or both of these capes. A large proportion of this fauna is widely distributed from New England to the South Atlantic Bight, yet 22 northern species and 96 southern species have restricted distributions. Analysis of community-level studies also revealed regional differences, especially between New England and southern states. These patterns are indicative of latitudinal variation and the transitional nature of this fauna. Given the strong representation of subtropical/tropical species and the prospects for continued warming of the ocean, we anticipate more species invasions and northward extensions of warm-water species along much of the east coast.