Invasive Seaweeds: Impacts and Management Actions

The introduction of alien seaweeds is continuously rising, due to the expansion of commercial transoceanic trade. oThis phenomenon can be intentional, mainly concerning economically important species introduced for cultivation purposes, or accidental, concerning species either associated to other imported organisms or attached on vessel hulls. oThe main vector for the accidental introduction of seaweeds are molluscs transferred throughout the world for both aquaculture and food purposes. oIntroduced seaweeds, which have a negative impact, are called invasive. Their biological invasion can produce damages at the level of biodiversity, ecosystem function and human health. oBiological pollution is the ensemble of damages caused by an invasive species. oOne species can not be defined invasive in an absolute sense, because its behaviour changes in time and in space. oIntroduced seaweeds can realise also positive effects, such as increasing of epibiont diversity. oBiological invasions can be effectively limited through the prevention of introduction and the correct management of human activities predisposing to the spread of invasive species. oNo effective solution was found for the prevention and the management of the introduction of alien seaweeds neither from science nor from policy to date. oAn urgent necessity of a regulation at both a national level but above all at an international level is claimed.