Why This Inexpensive Fish Should Stay Off Your Plate

There's no denying many popular types of quality seafood can be expensive. This can lead budget-conscious home cooks to consider lesser-known but lower-priced options found in the fish case. However, not all of them are worthy of a spot on your plate, regardless of cost. A perfect example is king mackerel, which should be avoided for mercury-related health concerns and its potentially polarizing flavor.

Naturally, the mercury issue is the more serious and significant of the two. In fact, the FDA explicitly warns young children and those who are pregnant or nursing should not consume king mackerel at all due to mercury concerns. King mackerel are among fish that contain the most mercury because of how this pollutant moves through the food system. Mercury that's emitted from sources like power plants eventually ends up in rivers, lakes, and oceans, where it's transformed into methylmercury, which builds up in the bodies of fish and shellfish. 

Although these amounts are generally small in any single creature, fish further up the food chain (such as king mackerel) consume many little fish over their lifetime, ingesting the small fish's mercury, too. This can build up to potentially hazardous levels over time. Children and infants are most at risk, as mercury can significantly affect their still-developing brains and nervous systems, although adults can experience adverse symptoms, such as loss of coordination, impaired speech, and muscle weakness. 

Beyond the potential health risks linked to mercury in king mackerel, others may feel it should stay off your plate because of its strong, somewhat polarizing taste and unusual appearance. It has a stronger, fishier flavor than other milder fish, as well as an oily texture. Meanwhile, the fish's flesh is described as greenish gray, an unappetizing look compared to many common, white-fleshed fish or the vibrant pinks and reds of salmon or tuna. Altogether, it's enough to earn king mackerel a spot among the top types of seafood you shouldn't be eating. 

Although many fish contain some level of mercury, king mackerel stands out among the pack. Only a few are known to typically have high levels (including swordfish and shark), while tuna, grouper, Chilean sea bass, and halibut typically have lower levels.

To be sure, cost-conscious shoppers looking to add some seafood to their diet may be tempted by the relatively affordable price, often in the $5 to $6 per pound range. However, there are better budget-friendly seafood options out there. For example, whiting filets are often found for similar prices. Another superior choice is Spanish mackerel, which offers a milder taste, lower mercury, and comparable prices. So, with serious downsides and many alternatives available, it's no wonder most agree that king mackerel should be skipped, no matter how attractive the price tag.