Fish is widely regarded as the healthiest meat. Fatty fish in particular are a good source of omega-3 fatty acids. However due to pollution, we should watch our intake of seafood and be selective about the fish we eat. Certain fish have especially high levels of mercury and PCBs. Fish used in fast food are typically low in mercury, but may be unhealthy for other reasons. Anything labeled "Sushi Grade" has been frozen to kill parasites based on FDA raw seafood consumption guidelines. It's more of a marketing term, so no other inferences can be made about its healthiness. In fact, freezing may not be enough to kill all of the bacteria present in fish used as sushi.

Pacific seafood & Beyond Organic's recommendation ...

The Fukushima nuclear disaster occurred in March of 2011, and it's been a few years now since a large plume of radioactive material entered the Pacific ocean and the atmosphere. Unfortunately there is no leveling off of the amount of damage created by this incident. TEPCO continues to cool the reactor with hundreds of thousands of water and releasing it into the ocean for lack of a suitable plan. Migratory fish and radioactive debris are already present  on U.S. shores. Fish in particular will have a tendency to bioaccumulate the radioactive material. Sadly, it's no longer safe to eat seafood from the west coast. Nor would we recommend seafood from the Gulf of Mexico just yet. The quality of the seafood in the Gulf of Mexico is devastated from the BP oil spill. Atlantic seafood was never the best choice due to industrial chemicals spilling in the ocean, but it's the lesser of all evils and ok to eat sparingly. So what if any seafood is safe to eat? I'm personally comfortable with the responsibly farmed salmon at Whole Foods which is mainly sourced in Europe and held to strict standards. They outline the requirements in their Quality Standards for Farmed Seafood.

WHAT TO LOOK FOR	WHAT TO AVOID
Fish with least mercury according to the charts and maps below Whole Foods salmon and shrimp	Most farm raised, due to run-off from land waste and unhealthy feed Large fish with greater longevity such as swordfish (see chart) Farmed salmon is high in PCBs, toxins. (except Whole Foods salmon) Fish caught off the U.S. East Coast Seafood from Gulf of Mexico (oil spill) Pacific coast seafood (Fukushima nuclear disaster)

The EPA recommends checking local fish advisories first in assessing the levels of contaminants in fish and the water. Advisories are publicly available on each state's website, which are easily accessible from the EPA Fish Advisories web page located at http://fishadvisoryonline.epa.gov/General.aspx.

Fish Advisories by State - 2010 (click to magnify)

Source: EPA, 2010 National Listing of Fish Advisories

An area with "0" advisories does not necessarily mean it has pristine waters. Where no advisory information is available, the chart below provides a baseline of mercury/ methylmercury levels in fish and shellfish (compiled from data found in the FDA and EPA websites). Fish high in PCBs and other contaminants are represented with an asterisk, and that should be factored into your seafood intake (the Max Consumption Limit column relates to Mercury levels only). While seafood consumption recommendations have been outlined, it should be noted that there is no "safe" level of mercury according to the World Health Organization. These consumption limits take into account our body's ability to eliminate mercury from our system. Women who are pregnant need to be even more careful with the fish they eat. Mercury, PCBs, and other contaminants are passed on to newborns when nursing, and the concentrated levels of contaminants have an adverse impact on child development.

Mercury Levels in Fish & Shellfish

Species       v	Avg Mercury  (PPM)	Max Consumption Limit
Anchovies	0.017	unrestricted
Bass (Saltwater, Black, Striped, Sea, Striped, Rockfish)	0.152	4 meals/month
Bass (Chilean Sea)	0.354	2 meals/month
Bluefish*	0.368	2 meals/month
Buffalofish	0.137	4 meals/month
Butterfish	0.058	16 meals/month
Carp	0.110	8 meals/month
Catfish (U.S. Farmed, not Imported*)	0.025	unrestricted
Clam	0.009	unrestricted
Cod*	0.111	8 meals/month
Crab (U.S. King, Snow, not Blue*)	0.065	12 meals/month
Crawfish (from U.S., not China*)	0.033	16 meals/month
Croaker Atlantic (Atlantic)	0.065	12 meals/month
Croaker White (Pacific)	0.287	3 meals/month
Flatfish (Flounder*, Sole*, Plaice)	0.056	16 meals/month
Grouper (all species)	0.448	2 meals/month
Haddock*	0.055	16 meals/month
Hake (Silver or Red, not White*)	0.079	8 meals/month
Halibut	0.241	3 meals/month
Herring	0.084	16 meals/month
Jacksmelt	0.081	8 meals/month
Lobster (Northern/American)	0.107	8 meals/month
Lobster (species unknown)	0.166	4 meals/month
Lobster (Spiny from U.S., not Imported*)	0.093	8 meals/month
Mackerel Atlantic (N. Atlantic)	0.050	16 meals/month
Mackerel Chub (Pacific)	0.088	8 meals/month
Mackerel (King)	0.730	do not eat
Mackerel spanish (Gulf of Mexico)	0.454	2 meals/month
Mackerel spanish (S. Atlantic)	0.182	4 meals/month
Mahi Mahi	0.290	3 meals/month
Marlin	0.485	1 meal/month
Monkfish	0.181	4 meals/month
Mullet	0.050	16 meals/month
Orange Roughy	0.571	1 meal/month
Oysters (Farmed, not Wild*)	0.012	unrestricted
Perch (Freshwater)	0.150	4 meals/month
Perch (Ocean)	0.121	4 meals/month
Pollock	0.031	16 meals/month
Rockfish*	0.219	4 meals/month
Sablefish	0.361	2 meals/month
Salmon* (fresh, frozen)	0.022	unrestricted
Salmon (canned)	0.008	unrestricted
Sardines	0.013	unrestricted
Scallop	0.003	unrestricted
Scorpionfish	0.233	3 meals/month
Shad (American)	0.045	12 meals/month
Shark	0.979	do not eat
Sheepshead	0.093	8 meals/month
Shrimp (U.S., not Imported*)	0.009	unrestricted
Skate	0.137	4 meals/month
Snapper	0.166	4 meals/month
Squid	0.023	unrestricted
Swordfish	0.995	do not eat
Tilapia (U.S., not Imported*)	0.013	unrestricted
Tilefish (Atlantic)	0.144	4 meals/month
Tilefish (Gulf of Mexico, S. Atlantic)	1.450	do not eat
Trout (Freshwater)	0.071	12 meals/month
Tuna (canned, Albacore)	0.350	2 meals/month
Tuna (canned, light)	0.128	4 meals/month
Tuna (fresh/ frozen, all)	0.391	2 meals/month
Tuna (fresh/frozen, Albacore*)	0.358	2 meals/month
Tuna (Bigeye*)	0.689	1 meal/month
Tuna (fresh/frozen, Skipjack)	0.144	4 meals/month
Tuna (Yellow Fin*)	0.354	2 meals/month
Tuna (fresh/frozen, species unknown)	0.415	2 meals/month
Weakfish (Sea Trout)	0.235	3 meals/month
Whitefish	0.089	8 meals/month
Whiting	0.051	16 meals/month

* Known to EDF to contain a high level of PCBs or other contaminants

Source: EPA, Origin of 1 meal / week Freshwater Fish Consumption Rate 2004
Source: EDF, Seafood Selector
Source: NRDC, Consumer Guide to Mercury in Fish