Zoological Studies 38(4): 452-457 (1999) Strontium Bands in Relation to Age Marks in Otoliths of European

relation to age marks in otoliths of European eel Anguilla anguilla. Zoological Studies 38(4): 452-457. Higher-concentration 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 elec-tron 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