Evaluation of a stable-isotope labelling technique for mass marking fin rays of age-0 lake sturgeon

P>The effectiveness of marking age-0 lake sturgeon, Acipenser fulvescens Rafinesque, pectoral fin rays with a stable strontium isotope was evaluated. Age-0 lake sturgeon were reared in water spiked with 0 (control), 25, 50 or 100 mu g L-1 86SrC0(3) for 10 and 24 days; fish from each treatment group were retained for up to 120 days post-labelling to assess mark retention. Enriched-isotope marks imparted to fin rays were distinct from fin ray 88Sr/86Sr ratios of control fish immediately following marking, with the 100 mu g L-1 86SrCO(3) treatments consistently yielding the highest rate of marking success (83-92%). Lower marking success (25-69%) was observed with the 25 and 50 mu g L-1 86SrCO(3) treatments. Isotopic marks in fin rays were retained for 120 days post-labelling. Immersion marking of juvenile fish pectoral fin rays with distinct strontium isotope ratios is possible and does not require sacrificing fish to check for marks.