example, the ctenophore Mnemiopsis leidyi (sea walnut) has 
depleted zooplankton, the main food source of the anchovy, 
and consequently contributed to the collapse of anchovy 
populations in the Black Sea, but this has not occurred in 
the Mediterranean Sea, the Baltic Sea or the North Sea (well 
established) {4.3.2.3}.
21SUMMARY FOR POLICYMAKERS
19SUMMARY FOR POLICYMAKERS
BACKGROUND
Figure SPM 2 Examples of invasive alien species with a negative impact on nature (green), 
and, in some cases, nature's contributions to people (yellow) and/or good 
quality of life (teal). 