Where do the dolphins and orcas that are held in European aquariums originate from?

From many sources – some from the wild, some bred in captivity while others are moved between parks. For example, the orcas in Loro Parque in Tenerife are on loan from Sea World in the US. There is no institution within Europe that provides transparent access to information documenting the shipments of dolphins between European facilities, so information is hard to obtain.