The Mediterranean is a remnant of a prehistoric ocean called Tethys, a mass of equatorial water dividing Pangea into two mega continents. The turbulent geological history of the Mediterranean created an ecosystem that we know today. Droughts and floods, ice ages and warm periods caused mass migration waves of boreal (northern) and subtropical animals. The interchanging warm and cold periods with hydrological characteristics of the Mediterranean basin has created an „intersection“ of marine biodiversity within which tropical and boreal species are found. Marine and coastal area is known for its richness and biological diversity of species, distributed in the 25 „biodiversity hotspots“ that are characterized by a high degree of endemism and critical loss of habitats. Endemism is an important characteristic of the Mediterranean, which means that many species live exclusively in the area, and this may include up to 30% of the overall life of the Mediterranean.