In shellfish, the highest levels of MeHgþ were found for prawn-1 (0.011 mg kg1). The concentrations of all samples were within the maximum levels set by (EC) No. 1881/ 2006 for MeHgþ (Commission Regulation (EC) No 1881/2006), except for red porgy-1 and -2 (Brazilian fish samples), tuna-3 and swordfish-1 (Spanish fish samples), which showed concentrations higher than 1 mg kg1. In some samples, iHg was also identified. Table 4 shows that values of iHg concentration ranged from 0.010 to 0.085 mg iHg kg1 in wm in fish samples; and from 0.006 to 0.016 mg iHg kg1 in wm in shellfish samples. However, iHg was quantified only in four of the eight shellfish samples. These data underline the importance of speciation in seafood samples. Speciation makes it possible to establish which the most harmful form to humans is and, therefore, whether the seafood is suitable or not for consumption. Likewise, the need to introduce maximum levels of MeHgþ in seafood in Brazilian and European legislatio should be considered in further Directives