, Volume 167, Issue 1, pp 75–84 | Cite as

Fitness consequences of individual specialisation in resource use and trophic morphology in European eels

  • Julien CucheroussetEmail author
  • Anthony Acou
  • Simon Blanchet
  • J. Robert  Britton
  • William R. C. Beaumont
  • Rodolphe E. Gozlan
Population ecology - Original Paper


Individual specialisation can lead to the exploitation of different trophic and habitat resources and the production of morphological variability within a population. Although the ecological causes of this phenomenon are relatively well known, its consequences on individual fitness are less recognised. We have investigated the extent of individual specialisation in resource use and trophic morphology and its fitness consequences through a combination of tagging–recapture, stable isotope analyses and telemetry. The European eel (Anguilla anguilla) was the model species as it displays significant variability in head shape. Independent to their body length, individuals with broader heads displayed a significantly higher trophic position (δ15N) than individuals with narrower heads. This corresponded with a significantly higher proportion of prey fish in their diet compared with invertebrates and was associated with the use of a habitat niche located further from the river bank. The European eel therefore provides a rare empirical example of individual specialisation in resource use and trophic morphology in a natural population occurring at a very small spatial scale. Individuals with intermediate head morphology displayed lower body condition (a proxy of fitness) than individuals with extreme head morphology (i.e. narrower and broader headed individuals), demonstrating the existence of disruptive selection associated with individual specialisation.


Niche segregation Disruptive selection Resource polymorphism Stable isotope analyses Interindividual variability 



We are grateful to the numerous individuals who participated in the field work and to D. Huteau and J.-M. Roussel for the loan of the portable antenna. Two anonymous reviewers provided very insightful comments on earlier versions of the manuscript. The research leading to these results has received funding from the European Community’s Seventh Framework Programme FP7-PEOPLE-2007-2-1-IEF under Grant agreement no. PIEF-GA-2008-219558.


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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Julien Cucherousset
    • 1
    • 2
    • 3
    Email author
  • Anthony Acou
    • 4
  • Simon Blanchet
    • 2
    • 3
    • 5
  • J. Robert  Britton
    • 1
  • William R. C. Beaumont
    • 6
  • Rodolphe E. Gozlan
    • 1
  1. 1.Centre for Conservation Ecology and Environmental Sciences, School of Applied SciencesBournemouth UniversityPooleUK
  2. 2.CNRS, UPS, ENFA, UMR5174Laboratoire EDB (Évolution et Diversité Biologique)ToulouseFrance
  3. 3.UPS, UMR5174, Laboratoire Évolution et Diversité Biologique (EDB)Université de ToulouseToulouseFrance
  4. 4.Muséum National d’Histoire Naturelle, UMR 7208 BOREA, Centre de Recherche et d’Enseignement des Systèmes CôtiersStation Marine de DinardDinardFrance
  5. 5.U.S.R. 2936Station d’Ecologie Expérimentale du CNRS à Moulis 09200MoulisFrance
  6. 6.Game and Wildlife Conservation TrustSalmon and Trout Research CentreWarehamUK

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