Predicting range expansion of invasive ctenophore Mnemiopsis leidyi A. agassiz 1865 under current environmental conditions and future climate change scenarios

Since the late 1990s, global warming has increased especially in Eurasia. With the temperature rising, the harmful invasive species such as « ecosystem engineer » Mnemiopsis leidyi spread into the seas of Eurasia and continues expanding around the world. Based on field data we defined the ranges of key environmental parameters (SST, SSS and Chl concentration) required for M. leidyi occurrence, reproduction and population growth in Eurasia. First, we evaluated the parameters separately and plotted global climatology of each of them for M. leidyi reproduction conditions. Next, we combined all parameters and determined the areas sufficient for M. leidyi occurrence, reproduction and sterile dispersal. Our results based on climatological data match well with field data on occurrence and reproduction and confirm the areas of its establishment in Eurasian seas. Since this climatological approach was successful, we extended it to the global scale. Results demonstrate the ability of M. leidyi establishment worldwide both at present and in future in the case of global warming prolongation. Model assessments predict accelerated SST rise in the Northern Hemisphere. As a result, waters previously too cold for M. leidyi reproduction could become favorable, which is especially true off the Arctic coasts of Eurasia. These areas in summer and autumn are expected to be much wider and extend closer to the North Pole. It is important to point out that all M. leidyi habitats including native, recipient and prospective ones are situated in shallow coastal areas and inland water bodies (semi-closed and closed seas, bays, lagoons, fjords). Equally important is that the local currents can provide only the relatively short distance of M. leidyi transport while shipping acts as the major vector.