Mussels are widely farmed and one of the most traded aquaculture products worldwide. As ecosystems engineers, mussel’s clusters constitute hotspots of biodiversity in terms of the associated fauna. Therefore, given the huge and broad mussel international market, usually consisting in imports of live and acclimatized specimens, unintentional introductions of associated or “hitchhiking” species may occur potentially inducing relevant impacts on receiving habitats. Indeed, aquaculture international imports of live organisms have been associated to incidental transport of non-indigenous species (NIS), being particularly relevant whenever the introduced species become invasive. Nevertheless, it has been recognized that the success of invasive species depends more on their particular traits rather than on a random process of selection of species.
The epifauna associated to mussels farmed (Mytilus galloprovinciallis) in southern coast of Portugal was identified and quantified in order to assess the species with spreading potential through commercial transport. Overall, the study aimed to: i) characterize the epi- and endofaunal communities associated to mussel clusters from an offshore aquaculture; ii) assess the biogeographic distribution of associated species across mussel transposition areas; iii) identify the associated species with spreading potential in mussel destination areas through a functional/behavioral approach.
Among 105 associated species, 44 were not previously reported in at least one of the common mussel export/transposition countries. Among those taxa, fouling species such as the anemones Paractinia striata and Urticina felina, the acorn barnacles Balanus glandula and Balanus trigonus, or the bryozoans Bugulina stolonifera and Schizoporella errata, exhibit functional attributes that allow them colonizing and spreading into new geographical areas. In this context, predicting and preventing the spread of NIS is a crucial challenge for the scientific community involved in this research field.