Introduced Species- 41°34'43.88"N 29°45'20.21"E

Mnemiopsis leidyi is a species of comb jellyfish that was originally native to western Atlantic waters. It was introduced to the Black Sea in the 1980s, where only one species of comb jelly existed. The most likely cause of its introduction is accidentally by merchant ships' ballast water.Since then it has made its way around the Mediterranean Basin. The damage it has cost is still uknown, but it has triggered the catastrophic collapse of local fisheries and overwhelmed the ecosystem.