Colonization record of Isognomon bicolor (Mollusca: Bivalvia) on pipeline monobuoys in the Brazilian south coast

摘要

Background The introduction of alien species in a system affecting native species due to competition for food and space. The purse oyster Isognomon bicolor (Bivalvia, Pteriidae), a potential exotic invader, presents gaps in its distribution and ecology knowledge in Brazilian coast. For this reason, our objective was to investigate the occurrence of this oyster on pipeline monobuoys in Rio Grande do Sul, southern Brazil. Specimens were collected monthly during surveys carried out from March 2010 to June 2011 at the Tramandaí Beach, along two pipeline monobuoys, MN-601 and MN-602, randomly from the depths of three and 22?m. Results We found I. bicolor dwelling on artificial hard substrates present in the Rio Grande do Sul coast, Brazil. This Caribbean bivalve was accidentally introduced to the Brazilian coast by ballast water from ships and, until now; it had not been recorded on the coast of Rio Grande do Sul state, which is under subtropical conditions. Conclusions The occurrence of I. bicolor in the faunistic surveys accomplished in the Rio Grande do Sul coast represents the first documented record for this species in this region. As this species is a potential exotic invader, with a high dispersal capacity, control measures must be employed to prevent its spread.