title: Eel migration to the Sargasso: remarkably high swimming efficiency and low energy costs.
abstract: One of the mysteries of the animal kingdom is the long-distance migration (5000-6000 km) of the European eel Anguilla anguilla L. from the coasts of Europe to its spawning grounds in the Sargasso Sea. The only evidence for the location of the spawning site of the European eel in the Sargasso Sea is the discovery by Johannes Schmidt at the beginning of the previous century of the smallest eel larvae (leptocephali) near the Sargasso Sea. For years it has been questioned whether the fasting eels have sufficient energy reserves to cover this enormous distance. We have tested Schmidt's theory by placing eels in swim tunnels in the laboratory and allowing them to make a simulated migration of 5500 km. We find that eels swim 4-6 times more efficiently than non-eel-like fish. Our findings are an important advance in this field because they remove a central objection to Schmidt's theory by showing that their energy reserves are, in principle, sufficient for the migration. Conclusive proof of the Sargasso Sea theory is likely to come from satellite tracking technology.
authors.affiliation: Institute of Evolutionary and Ecological Sciences, Integrative Zoology, Leiden University, POB 9516, 2300 RA Leiden, The Netherlands. ginneken@LUMC.NL
authors.forename: Vincent
authors.initials: V
authors.lastname: van Ginneken
authors.forename: Erik
authors.initials: E
authors.lastname: Antonissen
authors.forename: Ulrike K
authors.initials: UK
authors.lastname: Müller
authors.forename: Ronald
authors.initials: R
authors.lastname: Booms
authors.forename: Ep
authors.initials: E
authors.lastname: Eding
authors.forename: Johan
authors.initials: J
authors.lastname: Verreth
authors.forename: Guido
authors.initials: G
authors.lastname: van den Thillart
mesh_terms: D000811:Anguilla / Q000502:physiology*; D025041:Animal Migration; D000818:Animals; D001267:Atlantic Ocean; D001696:Biomechanical Phenomena; D001823:Body Composition; D004734:Energy Metabolism / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D013550:Swimming / Q000502:physiology*