MICROPROBE ANALYSES OF ANADROMOUS ARCTIC CHARR, SALVELINUS-ALPINUS, OTOLITHS TO INFER LIFE-HISTORY MIGRATION EVENTS

Otoliths of Arctic charr, Salvelinus alpinus, from north Labrador were examined to gather life history information pertinent to anadromous m igrations. Wavelength dispersive electron microprobe measurements conf irm the presence of strontium in otolith tissue. Trace element analyse s of charr otoliths imply that otolith strontium/calcium concentration ratios are related to external environmental factors with salinity ha ving a great influence. Otoliths clearly record habitat shifts consist ent with migration across major salinity boundaries. Most charr first migrate to sea following at least 2 years in freshwater. Generally, wh en anadromy begins, it continues annually. Robust relationships in oto lith chemistry, combined with macrostructure patterns in field-capture d specimens, provide time-series data describing individual migrationa l histories. Validation studies are still required in order to couple information contained within daily increments with chemical analyses t o infer additional temporal events in diadromous migrations.