Stock Photo - 23 March 2021, Brandenburg, Werder (Havel): Young eels swim in transport boxes from which they are released by commercial fishermen into the Havel and its tributaries. A euro coin serves as a comparative size here. The stocking operations are necessary because the natural upstream migration of glass eels via the Elbe has come to an almost complete standstill as a result of industrialisation and locks. The glass eels were caught on the French Atlantic coast. By the time they reach there, they have already travelled some 4,500 kilometres from the Gulf of Mexico through the Atlantic on their one to two year migration. Photo: Jens Kalaene/dpa-Zentralbild/ZB. - Werder (Havel)/Brandenburg/Germany