Mercury content in shark species from the South-Eastern Brazilian coast.

We present here the first results of Hg concentrations in three small shark species (Rhizoprionodon lalandei, R. porosus and Mustelus higmani) from the SE Brazilian coast. Mercury concentrations in R. lalandei ranged from 21.5 to 280.0 ng.g-1 dry weight (d.w.) (average 74.6 ng.g-1 d.w.; 17.9 ng.g-1 wet weight). In R. porosus, concentrations ranged from 7.6 to 90.5 ng.g-1 d.w. (average 42.2 ng.g-1 d.w., 9.4 ng.g-1 wet weight), whereas in M. higmani, concentrations ranged from 13.0 to 162.8 ng.g-1 d.w. (average 54.9 ng.g-1 d.w., 13.4 ng.g-1 wet weight). These concentration ranges are very low compared with values reported for other large shark species of the Southwestern Atlantic Ocean. There was a significant positive correlation between Hg concentrations and individual size, suggesting that biomagnification is occurring in these animals.