Trace elements were determined in three areas of the right (RL) and left (LL) lobe of the liver obtained from a whale shark (Rhincodon typus) stranded in Mexico. Mean ± standard error concentrations in μg g-1 wet weight were for zinc (Zn) RL: 22.5 ± 2.1; LL: 26.5 ± 7.1, arsenic (As) RL: 33.0 ± 1.6; LL: 20.0 ± 9.9 and cadmium (Cd) RL: 15.5 ± 0.9; LL: 11.3 ± 3.7; copper (Cu) RL: 3.2 ± 0.3; LL: 2.2 ± 0.8, selenium (Se) RL: 0.5 ± 0.1; LL: 1.2 ± 0.6, mercury (Hg) RL: 0.06 ± 0.02; LL: 0.05 ± 0.004 and lead (Pb) RL: 0.05 ± 0.02; LL: 0.05 ± 0.01. Concentrations showed significant (P < 0.05) differences within the same lobe but not between lobes. The trace element levels found in this whale shark represent the baseline levels of the trophic base's health status in the study area.