Micro-PIXE studies of char populations in northern Canada

Micro-PIXE analysis of trace elements in otoliths has been used as the basi s for several projects on char, a fish that is important for aboriginal sub sistence fisheries in Arctic Canada. Life-history patterns were originally inferred from micro-PIXE line scans of Sr distribution. These were confirme d by superposition of Sr distribution patterns on optical images of otolith s of tag-recaptured fish. Char from various populations showed differentiat ion in otolith primordial Sr concentration; this enables us to differentiat e biological stocks and, it is hoped, eventually to assign individuals from mixed-stock fisheries to their stock of origin. Zn oscillations also corre late with annular structure and provide additional temporally constrained i nformation on fish habitat and behaviour. (C) 1999 Elsevier Science B.V. Al l rights reserved.