Concentrations of 137Cs in lynx (Lynx lynx) in relation to prey choice

Concentrations of 137Cs were determined in 747 lynxes killed in Norway during the period 1986-2001. Highly variable 137Cs concentrations and aggregated transfer coefficient values were observed, probably caused by variable 137Cs concentrations in prey and the lynx's extensive home ranges and roaming distances. Adult lynxes had higher 137Cs concentrations than sub-adults, and lynxes killed in regions with extensive reindeer grazing areas were more contaminated than others. A model with 137Cs deposition density, the year lynxes were killed, age, and extent of reindeer grazing area accounted for 50% of the variability in observed 137Cs concentrations. The analyses were equivocal regarding the influence of stomach content on 137Cs concentrations in lynx muscle, i.e., on the lynx's specialization in prey species. Gender was not significant. Information on caesium retention in lynx and better estimates of deposition densities in lynxes' home ranges are important for further elucidation of factors influencing 137Cs contamination in lynxes.