Blue shark (Prionace glauca) and shortfin mako (Isurus oxyrinchus) specimens were caught in the North-eastern A tlantic O cean by S panish and Portuguese longliners. They are considered as top-predators, particularly susceptible to bioaccumulate mercury (Hg). The H g mean levels in blue shark and shortfin mako were 0.4 (SD = 0.3 mg kg-1) and 0.5 (SD = 0.9 mg kg-1), respectively. The body mass index (BMI) was tested to demonstrate the accumulation of H g in these two top-predators, taking into account size (TL, cm) and mass (W, kg) simultaneously. The comparison of these three methods showed that the BMI could be a relevant biological indicator of the accumulative H g process for sharks. |