MEPS 308:231-241 (2006)  -  doi:10.3354/meps308231

Phenotypic plasticity of habitat use by three temperate eel species, Anguilla anguilla, A. japonica and A. rostrata

Françoise Daverat1,*, Karin E. Limburg2, Isabel Thibault3, Jen-Chieh Shiao4, Julian J. Dodson3, François Caron6, Wann-Nian Tzeng7, Yoshiyuki Iizuka5, Håkan Wickström8

1Cemagref, 50 Avenue de Verdun, 33612 Cestas, France
2SUNY College of Environmental Science & Forestry, Syracuse, New York 13210, USA
3Département de Biologie, Université Laval, Ste-Foy, Québec G1K 7P4, Canada
4Institute of Cellular and Organismic Biology, and 5Institute of Earth Sciences, Academia Sinica, 128, Section 2, Academia Road, Nankang, Taipei, Taiwan 115, ROC
6Ministère des Ressources Naturelles et de la Faune du Québec, 675, boul. René-Lévesque Est, Québec (Québec) G1R 5V7, Canada
7Institute of Fisheries Science, College of Life Science, National Taiwan University, Taipei, Taiwan 106, ROC
8Swedish Board of Fisheries, Institute of Freshwater Research, SE-178 93, Drottningholm, Sweden

ABSTRACT: Habitat use patterns of 3 species of temperate eels, Anguilla anguilla, A. japonica and A. rostrata, were investigated using otolith strontium:calcium ratio life history transects. Published and unpublished data from 6 sites (Canada, United States, Sweden, France, Taiwan and Japan) sampled across the geographical range of each eel species were compiled. Sr:Ca patterns indicated that the 3 species displayed similar patterns of habitat use. In all sites, patterns of habitat use consisted of either residency in one habitat (fresh, brackish, or marine) or movements between habitats. One movement pattern consisted of either a single change or 2 changes of habitat from fresh to brackish waters, or from brackish water to freshwater. Seasonal movements between fresh and brackish waters were observed for all 3 species. When only a single habitat switch event was detected, it occurred between 3 and 5 yr of age. Occurrence of eels with no freshwater experience was demonstrated, but such eels accounted for a smaller proportion of the overall sample than eels with some (even brief) freshwater experience. Contrary to the common convention that these are obligate catadromous species, we must now consider them as facultative catadromous, with far more flexibility in habitat use. The most variable parameter among study sites was the relative proportion, rather than the diversity, of lifetime spent in the various habitat use patterns. Eels found at higher latitudes exhibited a greater probability of remaining in the lower reaches of watersheds in brackish water. Diversity of habitat use appears to be a common strategy of temperate eel species, and, as a life history tactic, is under environmental control.

KEY WORDS: Habitat use · Anguilla spp · Otolith Sr:Ca

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