The dish is beloved in China, but in the United States and Europe, it’s considered an invasive species.
Hairy crabs—so called because of the hairs on their claws—are a seasonal delicacy in China, where they’re consumed by the tons every autumn. The months between September and December are especially busy for crab farmers such as Xu Jianqing, who can make up to $11 for each crab sold.
The crustaceans are prized for their creamy roe and juicy meat. Male crabs can grow to the size of an iPhone, making them a hefty source of protein. The roe is often used in xiaolongbao 小笼包, or soup dumplings, a culinary favorite of eastern China, though many folks just eat the crabs steamed and dipped in vinegar.
Hairy crabs are most associated with Shanghai, but connoisseurs say the best come from Yangcheng Lake in coastal Jiangsu Province, where Xu works. Every autumn, tourists will make the trip to Yangcheng Lake just to try the crabs. They’ve become so famous that some vendors reportedly raise their crabs elsewhere and place them in the lake for a few weeks in order to sell them as Yangcheng crabs.
But in the United States and Europe, the crabs are considered a pest. They’ve been known to clog waterways, steal fish bait, compete for food with other fish, and contain pathogens because they can survive in polluted waters. Importing them is illegal, and if you find one, local authorities recommend not throwing it back alive.
(Read more: Why Sichuan peppercorns aren’t as good in the U.S.)
How did a dish so beloved in China become a pariah in the States? Much of it has to do with culinary tradition.
The crabs are native to waters around East Asia, particularly coastal regions, where they can move between fresh and saltwater for reproduction. Their abundance and large size made them a prized protein. During peak season, Xu says he can sell 1,000 crabs a day.
In the West, where they’re also known as Chinese mitten crabs, the crustaceans are considered an invasive species, having likely made their way across the ocean aboard the ballast tanks of commercial ships. They’ve been sighted on the Hudson River in New York, the River Thames in London, and even Chesapeake Bay in Maryland, home to its own famous breed of crabs.
Over the years, various businesses have proposed sourcing hairy crabs from parts of the world where they’re considered invasive. But none have really materialized, and for now, the solution for most localities is to handle the populations on their own.