Invasion
Invasion Description
1st record: Sao Sebastao/Brazil/Sao Sebastao Channel (da Rocha and Monniot 1995)
Geographic Extent
Rio de Janeiro State/Brazil/Ilha Grande Bay (2014, Skinner et al. 2016); Sao Sebastao/Brazil/Sao Sebastao Channel (da Rocha and Monniot 1995); Santa Catarina State/Brazil/Armação do Itapocoroy Bay (26°46'10"S, 48°47'04"W, Kremer et al. 2008; da Rocha et al. 2009, Kremer et al. 2007 mussel farm); Sao Paulo area/Brazil/Atlanitc Ocean (Kremer and da Rocha 2016); Ilhabela to Niteroi/Brazil/Atlantic Ocean (Oricchio et al. 2019); Teixeira and Creed 2020
Vectors
| Level | Vector |
|---|---|
| Probable | Hull Fouling |
Regional Impacts
| Ecological Impact | Competition | |
| In fouling plate experiments in São Sebastião, Brazil, Didemnum perlucidum grew most rapidly on bare plates, and when other organisms settled, it grew at a much slower rate, but overgrew solitary organisms (barnacles, bivalves) in about 70% of the cases. However, encounters with algae, bryozoans, or colonial ascidians resulted in stand-offs in about 65% of cases (Dias et al. 2008). In similar experiments in Santa Catarina state, overgrown species, such as the barnacle Megabalanus coccopoma and the solitary ascidian Styela plicata survived overgrowth (Kremer et al. 2010). Didemnum perlucidum did not influence taxonomic richness or inhibit colonization by any species, and appeared to have only weak, sporadic effects (Kremer et al. 2010). These weak effects may have been due to low abundance at this site (Kremer and Rocha 2011). In a 3-species experimnent, D. perlucidum dominates over Botrylloides nigrer and Schizoporella errata when preators were excluded, during the summer (Oricchio and Dais 2020). | ||
| Economic Impact | Fisheries | |
| Didemnum perlucidum was common but not dominant in mussel farms in southern Brazil. It does overgrow mussels, so could 'be damaging to the bivalve industry' (da Rocha et al. 2010). In later studies, D. pelucidum was found to affect the growth of cultuered mussels, delying or preventing their growth to maretable size. Monthly cleaning of the mussels and the culture 'socks' improved the growth of the mussels, but increased labor costs, (Lins and Rocha 2020). | ||