Trace elements in the silky shark Carcharhinus falciformis in the Central Pacific Mexican Shelf

Mercury (Hg), cadmium (Cd) and copper (Cu) concentrations were determined in muscle, liver and fin of the silky shark (Carcharhinus falciformis) caught in the Central Pacific Mexican Shelf. Liver tissue presented the highest concentrations of Cd (2.83 μg g^-1 wet weight (ww)) and Cu (2.34 μg g^-1 ww). For muscle and fin, Cu presented the highest concentrations (0.97 and 1.80 μg g^-1 ww, respectively). Liver concentrations were influenced by the maturation stages for the three elements. Immature organisms exhibited lower trace element concentrations than adults. No significant differences were found between sexes, except for Cu concentrations in muscle, where adult females present higher levels than adult males. One muscle sample (2.3 %) exceeded the Mexican Legislation for Hg (1.0 μg g^-1 ww) and five muscles samples (11.6 %) exceeded the Mexican limit for Cd (0.5 μg g^-1 ww). Meat consumption of this species can be a risk to human health if it is ingested regularly.