Transitions of Mnemiopsis leidyi (Ctenophora: Lobata) from a native to an exotic species: a review

The genus Mnemiopsis is comprised of a single species, Mnemiopsis leidyi A. Agassiz, 1865, that has recently made the transition from a distribution limited to the Atlantic coasts of North and South America to an invasive range that includes the Black, Caspian, Mediterranean, North, and Baltic seas. We review the foundations of the ctenophore’s invasive success, which include the source-sink dynamics that characterize Mnemiopsis populations in temperate coastal waters where the ctenophore achieves its highest biomass levels and ecosystem impacts. Within its native temperate range, Mnemiopsis is frequently a dominant, seasonal, colonizing species with limited dispersal capacities. Cross-oceanic transport within ballast waters of intercontinental shipping vessels has altered this dispersal limitation and initiated a rapid global spread of Mnemiopsis. Owing to continuing transport via transoceanic shipping, we anticipate continued range expansion and review the variables most likely to determine whether introduction of Mnemiopsis to a novel community results in an inconspicuous addition or a disruptive invasion.