The European Food Safety Authority (EFSA) is the keystone of European Union (EU) risk assessment regarding food and feed safety. In close collaboration with national authorities and in open consultation with its stakeholders, EFSA provides independent scientific advice and clear communication on existing and emerging risks.

In December 2004, EFSA was requested by the European Parliament to conduct a scientific assessment of health risk related to human consumption of wild and farmed fish. EFSA's opinion (EFSA Journal (2005) 236, 1-118) focused on eight finfish species which are widely available in the EU and likely to be consumed most frequently: salmon, herring, anchovies, tuna, mackerel, pilchards, rainbow trout and carp. Of these, salmon, rainbow trout and carp are predominantly or exclusively farmed. Currently, about two-thirds of fish consumed in the EU is caught from the wild.

According to EFSA, the highest levels of methylmercury are found in tuna, which is mostly caught from the wild. Highest levels of PCDD/F and DL-PCBs are found in herring, which are caught from the wild, and salmon, which are mostly farmed. 

Overall EFSA concluded that, with respect to consumer safety, farmed fish is not less safe than wild fish.  Source: Consensus report 'Towards Sustainable Aquaculture in Europe'