What we know and don't know about the invasive golden mussel Limnoperna fortunei

An overview of the knowledge of the invasive feshwater golden mussel (Limnoperna fortunei) is presented, with particular emphasis on the voids of our current understanding of its ecology and its effects on the systems invaded. L. fortunei started spreading northwards in China after 1960, and similar to 1990 it invaded Japan and South America. These invasions fostered a strong increase in the interest in the mussel. However, coverage of its biology, ecology, and impacts has been very uneven. Geographic distribution and spread, seasonal dynamics and methods for controlling its fouling in industrial plants and other human-made facilities have received most of the attention, while many other important issues (e.g., multiannual density changes, competition with native organisms, predation by invertebrates, reptiles, birds, and mammals) lag far behind. The effects of the golden mussel on environmental traits and resident organisms have been investigated almost exclusively in laboratory or mesocosm settings, but extrapolation of these results to waterbody scales is contentious, mainly because system-wide densities are largely unknown. The information available suggests that most environmental impacts of L. fortunei are mixed, context- and stakeholder-dependent, with both positive and negative effects. In contrast, its impacts on human-made facilities and infrastructure are clearly always negative and costly.