No longer the pristine confines of the world ocean: a survey of exotic marine species in the southwestern Atlantic

ORENSANZ, JOSE MARIA (LOBO) ; SCHWINDT, EVANGELINA ; PASTORINO, G.; BORTOLUS, ALEJANDRO ; CASAS, GRACIELA ; DARRIGRAN, GUSTAVO ; ELÍAS, RODOLFO ; LÓPEZ GAPPA, JUAN J. ; OBENAT, SANDRA ; PASCUAL, MARCELA ; PENCHASZADEH, P. E.; PIRIZ, MARÍA LUZ ; SCARABINO, FABRIZIO ; SPIVAK, EDUARDO D. ; VALLARINO, EDUARDO A.

BIOLOGICAL INVASIONS

SPRINGER

Lugar: Berlin; Año: 2002 vol. 4 p. 115 - 143

1387-3547

We conducted a comprehensive survey of existing knowledge about exotic marine organisms introduced to thesouthwestern Atlantic Ocean, including coastal and shelf areas of Uruguay and Argentina. This domain is equivalentto the so-called Patagonian Shelf Large Marine Ecosystem, and corresponds to two biogeographic provinces: warmtemperate(Argentine Province) and cold temperate (Magellanic Province). The search included species that canbe confidently categorized as introduced (31) and cryptogenic species (46). We present a comprehensive pictureof recorded introductions (the first for this region) and some prominent ecological consequences. Most coastalecosystems between the La Plata River estuary and central Patagonia have already been modified, or are expected tobe so in the short term. Five recent, human-mediated biological invasions have already had a significant ecologicalimpact. A barnacle (Balanus glandula) belt has developed on all rocky shores where none was present 30 yearsago, a macro-fouler (Limnoperna fortunei) and a reef-builder (Ficopomatus enigmaticus) have strongly modifiedestuarine ecosystems, Pacific oyster (Crassostrea gigas) reefs are expanding in shallow bays at a fast rate, and kelp(Undaria pinnatifida) is rapidly modifying nearshore benthic communities along the coasts of central Patagonia.At this point, it is uncertain how many of the cordgrasses (Spartina spp.) found in coastal salt marshes correspondto exotic forms. Only exposed sandy beaches appear to be free from the pervasive ecological impact of invasion byexotic species. Poor knowledge of the regional biota makes it difficult to track invasions.