Mercury Risk: Low
Most of the true squid sushi (ika) served in U.S. sushi restaurants is flown in from Japan, but occasionally domestic product is used, usually in appetizers.
There are three main types of domestic squid available in the United States—long-fin, short-fin, and Humboldt or jumbo squid. Long-fin and short-fin squid are small in size and are caught in the Atlantic Ocean. The much larger Humboldt squid, which can easily exceed three feet in length, are found along the U.S. West Coast or the Gulf of California in Mexico. Unfortunately for the consumer, it is nearly impossible to tell these species apart when they are prepared as your dinner.
Oftentimes the “squid” available in sushi restaurants isn’t squid at all—it’s cuttlefish, a related but distinctly different species. Most of these cuttlefish come from the waters around Vietnam. Unfortunately, very little is known about this fishery, so it is difficult to make an informed recommendation. As always, it is best to use moderation when dealing with the unknown.
Squid grow quickly, reach maturity within a single year, and reproduce in large numbers. These characteristics help to keep populations strong even when they are heavily fished. These animals also generally school over sandy habitats, which are more resilient to the effects of trawling than rocky areas. However, no sea creature is immune to depletion and devastation if exploited too heavily—squid may have a number of factors on their side, but there is still little known about actual population dynamics.
If possible, try to aim for long-fin squid from the East Coast; more is known about this fishery than about the others, and it seems to be fairly well-managed with strong populations. In general, squid is a good alternative to less sustainable options at the sushi bar.