title: Recruitment collapse and population structure of the European eel shaped by local ocean current dynamics.
abstract: Worldwide, exploited marine fish stocks are under threat of collapse [1]. Although the drivers behind such collapses are diverse, it is becoming evident that failure to consider evolutionary processes in fisheries management can have drastic consequences on a species' long-term viability [2]. The European eel (Anguilla anguilla; Linnaeus, 1758) is no exception: not only does the steep decline in recruitment observed in the 1980s [3, 4] remain largely unexplained, the punctual detection of genetic structure also raises questions regarding the existence of a single panmictic population [5-7]. With its extended Transatlantic dispersal, pinpointing the role of ocean dynamics is crucial to understand both the population structure and the widespread decline of this species. Hence, we combined dispersal simulations using a half century of high-resolution ocean model data with population genetics tools. We show that regional atmospherically driven ocean current variations in the Sargasso Sea were the major driver of the onset of the sharp decline in eel recruitment in the beginning of the 1980s. The simulations combined with genotyping of natural coastal eel populations furthermore suggest that unexpected evidence of coastal genetic differentiation is consistent with cryptic female philopatric behavior within the Sargasso Sea. Such results demonstrate the key constraint of the variable oceanic environment on the European eel population.
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany. Electronic address: msoares@geomar.de.
authors.forename: Miguel
authors.initials: M
authors.lastname: Baltazar-Soares
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany.
authors.forename: Arne
authors.initials: A
authors.lastname: Biastoch
authors.affiliation: School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK; Instituto de Ciencias Naturales Alexander Von Humboldt, Universidad de Antofagasta, Avenida Angamos 601, Antofagasta, Chile.
authors.forename: Chris
authors.initials: C
authors.lastname: Harrod
authors.affiliation: Thünen-Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg, Germany.
authors.forename: Reinhold
authors.initials: R
authors.lastname: Hanel
authors.affiliation: Thünen-Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg, Germany.
authors.forename: Lasse
authors.initials: L
authors.lastname: Marohn
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany.
authors.forename: Enno
authors.initials: E
authors.lastname: Prigge
authors.affiliation: Fisheries and Aquatic Ecosystems Branch, Agri-Food and Biosciences Institute, Newforge Lane, Belfast BT9 5PX, UK.
authors.forename: Derek
authors.initials: D
authors.lastname: Evans
authors.affiliation: School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Bodles
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany.
authors.forename: Erik
authors.initials: E
authors.lastname: Behrens
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany.
authors.forename: Claus W
authors.initials: CW
authors.lastname: Böning
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany; School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK.
authors.forename: Christophe
authors.initials: C
authors.lastname: Eizaguirre
mesh_terms: D000811:Anguilla / Q000502:physiology*; D025041:Animal Migration; D000818:Animals; D001267:Atlantic Ocean; D005828:Genetics, Population; D008954:Models, Biological