Bohai swimming crab

Bohai swimming crab

　　[Morphological Features]: The carapace is spindle-shaped and slightly raised. The surface has three prominent wart-like protrusions—one in the gastric region and two in the cardiac region. Its body is oval-shaped, with pointed ends resembling a weaving shuttle, hence the name "three-spined swimming crab." Each of the two front lateral edges has nine teeth, with the ninth tooth being particularly long and extending sideways. The frontal margin has four small teeth. On either side of the frontal area are a pair of rotatable stalked compound eyes. There are five pairs of thoracic legs. The chelipeds are well developed, with the merus being prism-shaped and having blunt teeth on the inner edge. The fourth pair of walking legs has flattened, broad, and thin dactyls resembling paddles, suitable for swimming. The abdomen is flat (commonly referred to as the “crab’s navel”), triangular in males and rounded in females. The dorsal side of males is dark greenish tea-colored, while that of females is purple, and the ventral side is grayish-white for both.

　　[Production Area and Season]: The peak production seasons are from March to May and September to October. In the Bohai Bay around the Liaodong Peninsula, production is particularly abundant from April to May.

　　[Ecological Habits]: This is a large, warm-temperate, perennial crab species and also the largest crab species in China. It is adept at swimming and digging through mud and sand, often lurking near the seabed or estuaries. It is fierce and combative, highly reproductive, and grows quickly. At the end of March, crab groups migrate to shallow waters to spawn, with egg-bearing crabs reaching up to 750 grams in weight. Mid to late April marks the peak spawning period. From the first juvenile stage to maturity, it generally takes about three years. Inshore spawning grounds have over 80% female crabs, while offshore areas have more males. The main fishing season is in April. According to veteran fishermen, winter temperatures or the water temperature of the overwintering grounds significantly affect the crab catch. Around Grain Rain, crabs are at their plumpest, although they can still be caught in autumn, they are not as plump (though pre-overwintering males are especially full and large, known as “grain-stubble male crabs”). Males are commonly called “pointed-navel crabs,” immature males are called “thin-navel crabs,” and females are called “round-navel crabs.” Females are preferred, and those carrying eggs are also known as “pomegranate-yellow crabs.” The market price difference between male and female crabs is substantial. The crab meat is white, abundant, tender, and the roe is smooth like congealed fat, making it delicious. Especially the meat of the two pincer-like chelipeds is thread-like with a sweet taste, and the crab roe is brightly colored and aromatic, offering a unique flavor, which is why it has long been famous and ranked as the best among seafood.