In the mid 1980s, research undertaken by the International Agency for Research on Cancer (IARC) demonstrated that some polycyclic aromatic hydrocarbons (PAHs) can have either carcinogenic and mutagenic or genotoxic potential (Costa, 2001). Due to their toxic potential and their nature as ubiquitous contaminants in the environment, it is important to monitor their presence and availability in different ecosystems. PAHs can reach the marine environment by many routes, such as atmospheric deposition of particles of incomplete combusted organic matter, urban runoff, industrial and domestic waste and oil spills during oil production and oil transport (Newman and Unger, 2003; Hoffman, 2003; Jonsson et al., 2004). These spills mainly affect the coastal area where petroleum extraction, transport and refineries are concentrated. The PAHs present in the water column are available to marine fish via different uptake routes, such as diet and/or through direct transport across external membranes (Richardson et al., 2004). After absorption and distribution, these compounds are readily metabolized, chiefly by the cytochrome P-450 enzymes of Phase I, to a more hydrophilic compound and then conjugated by Phase II enzymes and excreted to the gallbladder (van der Oost et al., 2003). Although some studies show that PAHs can be accumulated in fish tissue (Hellou et al., 2002; Hellou and Leonard, 2004), its biotransformation is rapid and the exposure of fish to PAHs is difficult to detect by chemical analysis of the edible fish tissue or other organs as the liver (van der Oost et al., 1994; Aas et al., 2000; Richardson et al., 2004). Besides that, relationships between the occurrence of neoplasia and liver tumors in fish and the concentration