Mercury moves up the food chain. When it falls as part of rain or snow, it contaminates our natural water sources. Mercury is taken up by small aquatic plants and animals which are consumed by bigger fish, which are then consumed by even bigger fish, so the mercury levels build up via a process called “bioaccumulation.” The Environmental Defense Fund advises against eating shark because of its high levels of mercury, and also because shark populations are at historically low levels as a result of overfishing. It’s estimated that half of the sharks killed each year are a result of bycatch.
5 KING MACKEREL (INSTEAD CHOOSE ATLANTIC MACKEREL)
This fish should be avoided completely. King Mackerel has some of the highest levels of mercury. The EPA recommends that woman and children avoid entirely and men should consume less than one serving per month (assuming no other contaminated fish are consumed). Why take the risk? As an alternative, Atlantic mackerel is low in mercury levels and has earned a “Best Choice” eco-rating from the Monterey Bay Aquarium’s Seafood Watch.
6 ATLANTIC COD
Atlantic cod has been overfished and has suffered massive population declines, according to chef Frankie Terzoli. In general, most Atlantic cod should be avoided or limited except for cod raised in recirculating aquaculture systems (RAS). These systems are maintained on land and the inputs and outputs are highly controlled, decreasing the impact on habitat. Their population sizes are also monitored.