What is Lessepsian migration?
[[File:TucacasDiodonHystrix colour adjusted.jpg|thumb|The [[Spot-fin porcupinefish]] is one of the species that migrated from the Red Sea to the Eastern Mediterranean]] [[File:Dicentrarchus labrax011.JPG|thumb|[[European seabass]], one of only a few species who migrated from the Mediterranean to the Red Sea.]] '''Lessepsian migration''' is the name given for the [[migration]] of [[Ocean|marine]] [[species]] through the [[Suez Canal]], between the [[Red Sea]] and the [[Mediterranean]]. It is named after [[Ferdinand de Lesseps]], who built the Suez Canal. The Suez Canal joined two [[biosphere]]s that were separate before. Many species migrated from the Red Sea to the Eastern Mediterranean. Only a few species migrated in the other direction, from the Mediterranean to the Red Sea. The migration can be seen most clearly when looking at [[fish]] species, even though other animals also migrated. When the Suez Canal was opened in 1869, it created the first salt-water passage between the Red Sea and the Mediterranean. The [[Bitter Lakes]] are two very salty ([[Salinity|hypersaline]]) lakes about mid-way in the canal. At first, this blocked the migration of species from the Red Sea to the Mediterranean. Over the last decades, the salinity of the lakes changed, which made it easier for species to migrate. The Red Sea is higher than the Mediterranean, at high tide, water flows from the Red Sea to the Mediterranean. The Red Sea is also poor in [[nutrient]]s, so species who migrate will find more nutrients. The waters of the Red Sea are saltier than that of the Mediterranean. For these reasons, most species migrate from the Red Sea to the Mediterranean, and only very few migrate in the other direction. When the [[Aswan High Dam]] was built in the 1960s, this blocked the flow of freshwater from the [[Nile]] into the Mediterranean. As a result, the salinity levels in the Eastern Mediterranean increase, and make it much more like the Red Sea – this means that migration will become even easier, as conditions are very similar