Swimming crabs up for grabs

"Once autumn arrives, crabs are at their plumpest."

So goes a fishermen's saying along the coast of Zhoushan in Zhejiang province, reflecting generations of knowledge about the seasonal rhythms of the sea.

As autumn winds set in and seawater cools, swimming crabs move from shallow waters toward deeper areas. Their meat becomes fuller, female crabs develop rich roe and males grow increasingly meaty.

This year's autumn equinox falls on Sept 23. As daylight hours shorten and seawater continues to cool, swimming crabs enter one of their peak seasons. For people along China's eastern coast, eating crab around the autumn equinox is a way to follow the seasons and enjoy the bounty of the sea.

Qiu Hongfang, a fishing proverb researcher and intangible cultural heritage preservation expert from Daishan county, Zhoushan, says swimming crabs can be found in local waters all year round, but are more abundant in spring, autumn and winter.

"When seawater temperatures rise in summer, swimming crabs stay in the upper layers and become relatively lean. Fishermen call them 'flying-water crabs'," Qiu says. "When autumn arrives and the water cools, they move into deeper waters and begin to put on weight."

A local saying captures the difference: "June crabs are thin and hollow; October crabs are strong and plump."

Zhoushan fishermen have long used such observations to track the crabs' seasonal cycle. Another saying goes, "Fish follow the tide, crabs follow the storm," referring to the way fish move with the tides while crabs become more active around changes in weather.

"By the beginning of winter, the crab disappears without a trace," says another proverb, describing how swimming crabs retreat into deeper waters as temperatures fall, according to Qiu.

For fishermen, watching the tides, wind and water temperature is a way of reading the rhythm of the sea.

Qiu also has three simple tips for choosing a good crab. First, look at the point where the shell meets the abdominal flap.

"If this area looks swollen and pushed outward, the crab is likely to be plump. The more pronounced it is, the fuller the crab," he says.

Second, compare the weight of two crabs. "The heavier one is usually the plumper one." Third, gently squeeze the crab's legs. "Soft legs indicate a lean crab; hard legs usually mean it is fuller."

For female crabs with prized red roe, Qiu says diners can also look at the pointed areas on either side of the shell. "The deeper the red color and the farther it extends toward the tips, the more roe the crab is likely to have."

In Zhoushan, people say, "A banquet is incomplete without crab."

Steaming remains the classic preparation, allowing the crab's natural sweetness to take center stage. Other local dishes include scallion-oil crab, roasted and deep-fried crab, as well as crab stir-fried with potatoes or rice cakes. Red-roe female crabs are also prepared as qiangxie, a traditional salt-marinated crab dish.

For chef Chen Xuelin, originally from Changle, Fuzhou, swimming crab is also part of his memories of the taste of home.

"For people along the coasts of Fujian and Guangdong, swimming crabs are a familiar sight at this time of year," says Chen, executive chef of J&A Steak House in Xiamen, Fujian. "Once the fishing season opens in mid-August, you can find very good swimming crabs."

While steaming remains his preferred way to preserve the crab's natural sweetness, Chen also gives it a modern interpretation. He combines traditional Fuzhou crab sauce with French mayonnaise and adds lemon gel and finger lime to balance the richness and bring a burst of freshness.

From fishermen's proverbs and family memories to contemporary restaurant kitchens, swimming crab remains closely tied to the rhythm of the East China Sea. And around the autumn equinox, that connection is most vividly expressed on the plate.