Jellyfish on the rocks: bioinvasion threat of the international trade in aquarium live rock

So-called live rock - coral rock that harbours a vast array of marine organisms that enhance the aesthetics and function of aquariums - is an increasingly valuable commodity in the aquarium industry. Live rock is primarily collected from the edges of reefs in the Indo-Pacific, where its export is an important source of revenue for many small subsistence communities. The trade in live rock is not subject to quarantine restrictions in its principal markets, yet poses a serious threat of bioinvasion because of the potential for inadvertent or deliberate release of the organisms that reside on its surfaces. This threat is demonstrated here by the transportation of jellyfish polyps of a species of Cassiopea (Upside-down jellyfish) on live rock imported to the USA from the Indo-Pacific. Jellyfish have recently come into the spotlight as significant bioinvaders. The transportation of jellyfish on live rock provides the first direct evidence of a translocation vector for these organisms. Invasive species are a principal threat to biodiversity and are responsible for enormous economic losses globally. The unregulated trade in live rock presents a serious bioinvasion risk that warrants the urgent attention of regulatory bodies.