UBC Theses and Dissertations
The feasibility of using lanthanide elements to mass mark hatchery-production salmon Ennevor, Bridget Carroll
The development of a marking technique which could be effectively and efficiently used to mark large groups of salmonids, would be a great asset to fisheries management. Six experiments were thus conducted to investigate the feasibility of using the lanthanide elements to mass mark hatchery-production salmon. The lanthanides, introduced through the water supply, appear to be suitable since they demonstrate the characteristics of good elemental markers. Fish marked with these elements can be satisfactorily identified by analysis of bony tissues by inductively coupled plasma-mass spectrometry (ICP-MS). The lanthanides were shown to be severely toxic to coho and steelhead alevins at concentrations of 100 µg/l in the water supply, but were only slightly toxic to coho fry. Alevin and fry appeared to be more sensitive to the light-weight lanthanides than the heavier lanthanides. Coho smolts showed no adverse effects when exposed to lanthanum or cerium at these concentrations. Lanthanides, introduced in the form of acetates, were shown to be absorbed from the water supply and subsequently incorporated in the vertebral column, otoliths and scales of coho fry. Coho fry exposed to lanthanum or samarium at concentrations of 100 µg/l in the water for 6 weeks had detectable levels of element in their bony tissues 10½ months post-treatment. When lanthanum and cerium were added to the water supply at concentrations of 100 µg/l for 4 weeks, higher concentrations of element were accumulated in fry than in smolts, although smolts accumulated greater amounts of element. Introduction of the lanthanide elements through the water supply, appears to be an effective method for the mass marking of young salmonids.
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