Mercury Levels in the Worldwide Farmed Fish: A Systematic Review

Aquaculture, specifically farmed fish, contributes to global aquatic fish stuff production. The present study systematically reviewed mercury levels in farmed fish. One hundred two scientific articles were found in four databases. Only seven were considered appropriate, and eleven articles were added. In total, 18 articles are eligible for this review. Papers determining Hg in farmed fish were reported in seven countries: China, Korea, Pakistan, India, Brazil, the USA, and Poland. Fifty species from farmed fish were evaluated worldwide, and Ctenopharyngodon idella Glass carp, Oreochromis niloticus Tilapia, and Hypophthalmichthys nobilis (synonym of Aristichthys nobilis) Bighead carp have registered the highest frequency. The mercury values found in fish from the production system were low. For the risk analysis, only India presented values within tolerable limits; however, Korea and Pakistan showed high values, indicating a potential risk of consuming protein from farmed fish in these countries. Therefore, farmed fish are not Hg-free but safer than fish in nature due to greater control of biotic and abiotic factors in ponds, thus contributing to sustainable, productive economic activity.