Source: Wild, Farmed
Mercury Risk: Low
First of all, mirugai is not giant clam, ocean clam, or long-neck clam, regardless of what the menu may say. Mirugai is geoduck, pronounced “goo-wee-duk,” taken from a Nisqually Indian word meaning “to dig deep.” A large burrowing bivalve native to the Pacific Northwest, this animal can reach upwards of ten pounds and live for over a century.
These immense clams live about three feet under the sand for their entire adult lives. Harvesters dig them up using a high-pressure water wand or an open-ended can and a shovel. Historically, the demand for geoduck has been concentrated in Asia, where one plate of the delicious mollusk can fetch as much as a hundred dollars. Lately, however, the U.S. market for geoduck has exploded, due in no small part to increased demand in sushi bars.
There are two main sources of geoduck—Washington State and British Columbia. Both fisheries have wild and farmed components. Wild geoduck is harvested in Alaska as well, but on a smaller scale. Wild geoduck stocks have fluctuated in the past but are generally strong. Management techniques vary between US and Canadian fisheries, but overall they have been effective in protecting the stock health and regulating exploitation. When available, wild geoduck is a solid choice at the sushi bar.
Farmed geoduck looks to have a promising future as well. Although there are some problems and unanswered questions, mainly having to do with geoduck genetics, farmed geoduck seems to be much more sustainable than its wild counterpart. Farmed geoduck spares standing wild populations, disturbs fewer tide-flat and seabed areas, and creates less bycatch, or unintended species and juveniles that are caught and discarded.
Geoduck farms are superior to many other types of aquaculture in that they don’t use fish meal, antibiotics, or any other dietary supplements. Geoducks are filter-feeding herbivores and subsist entirely on algae that wash over their burrows when the tide comes in.
Geoduck is a good option at the sushi bar. As a step toward a healthier ocean, consider ordering mirugai instead of surf clam, wild abalone or conch, which are similar in taste and texture but far less sustainable.
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