Alien bryozoans in the fouling assemblage of Quequén Harbour (Argentina, Southwest Atlantic)

LIUZZI MG; LÓPEZ GAPPA J

Buenos Aires

Conferencia; Marine & Freshwater Invasive Species: Ecology, Impact, and Management; 2016

The bryozoan fauna reported for Argentine harboursencompasses at least 29 species, of which only nine are documented exotics andanother four were regarded as cryptogenic. In comparison with other marineharbours in the area, Quequén Harbour (QH) was thought to be characterized by arelatively low bryozoan diversity, probably due to its estuarine features. Twospecies had been previously recorded during a detailed taxonomic study of theirbryozoan assemblages: Cryptosulapallasiana (Moll) and Conopeumsp. Four other bryozoans had alsobeen listed for QH in the ecological literature, but their presence was notconfirmed by taxonomic studies or by voucher specimens deposited in museumcollections: Bugula flabellata(Thompson), Bugula neritina (Linné),Bowerbankia sp. and Conopeum reticulum (Linné). Forty-eightrectangular (210 ×260 × 3.5 mm)low-density polyethylene panels screwed to four vertical supporting structures weresuspended from a pier (38º 34.310´ S, 58º 42.814´ W) on September 20, 2012(winter) and collected on June 21, 2013 (autumn). In previous contributions, wereported the presence of four other alien species in QH: Fenestrulina delicia Winston et al., Zoobotryon verticillatum (Delle Chiaje), Aspidelectra melolontha (Landsborough)and Schizoporella errata (Waters). Inaddition, the alien Conopeum seurati(Canu), the cryptogenic Electramonostachys (Busk) and the native Membranipora puelcha (d?Orbigny) were recently discoveredencrusting the panel surfaces, and the presence of Conopeum reticulum was also confirmed. The total number ofbryozoans in QH reaches therefore 12 species. The increasing number of alienspecies in QH detected after 25 years highlights theimportance of performing periodical surveys in harbour environments, which arethe most common initial incursion sites used by non-indigenous species.