Decline of mercury in young fishes from western Lake Erie between 1970-71 and 1974

Concentrations of total mercury were determined for samples of age 0-II whole fish of six species collected from western Lake Erie in 1970-71 and five species collected in 1974. Within years, average total mercury concentrations increased with age and size in all species. The concentrations were significantly lower (37 to 86%) in 1974 than in 1970-71. Methylmercury concentrations and the proportion of methylmercury to total mercury increased with age and size of fish in samples of four species collected in 1970-71.