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Vol. 38 No. 4, 1999
Strontium Bands in Relation to Age Marks in Otoliths of European Eel Anguilla anguilla
Wann-Nian Tzeng1,*, Kenneth P. Severin2, Håkan Wickström3 and Chia-Hui Wang1
1Department of Zoology, College of Science, National Taiwan University, Taipei, Taiwan 106
2Department of Geology and Geophysics, University of Alaska Fairbanks, Alaska 99775-0760, USA
3National Board of Fisheries, Institute of Freshwater Research, S-178 93, Drottningholm, Sweden
Wann-Nian Tzeng, Kenneth P. Severin, Håkan Wickström and Chia-Hui Wang (1999) Higherconcentration strontium (Sr) bands and hyaline zones in otoliths of European eel, Anguilla anguilla
(L.), from both brackish waters and freshwater lakes were examined by
wavelength dispersive x-ray spectrometry on an electron microprobe and
by visible light microscopy, respectively. The positions of
higher-concentration (> 0.3 wt %) Sr bands and hyaline zones were
identical in otoliths of eels from brackish waters; however, no
corresponding higher-concentration Sr bands were discernible in
otoliths of eels from fresh water. The higher-concentration Sr bands
were deposited when the eels migrated from brackish water to
high-saline seawater during winter. The number of hyaline zones in the
otoliths corresponds to the age of the eel. Accordingly,
higher-concentration Sr bands in otoliths can be used to determine fish
age and migratory history in brackish waters.
Key words: European eel, Otolith, Strontium, Annulus.
*Correspondence: Tel: 886-2-23639570. Fax: 886-2-23636837.E-mail: wnt@ccms.ntu.edu.tw
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