What it is
Tsîm (蟳) is the Taiwanese name for the mud crab (Scylla serrata, 鋸緣青蟹), a heavy crab of Indo-Pacific estuaries and mangroves. Sellers grade it by sex and stage. A virgin crab (處女蟳) is an unmated female with tender meat and soft, half-set roe. A red crab (紅蟳) is a mated female with firm, chewy roe. Males (菜蟳) are prized for fine, sweet meat.
Where it came from
The red crab takes its name from the colour it turns in the pot, and folk custom treats it as a tonic (補品). It is a food for celebrations, and prices climb before Lunar New Year. The best-known festive dish is red crab with sticky rice (紅蟳米糕), a fixture of traditional outdoor banquets.
Taiwanese farmers raised the crab in earthen ponds, stocking them with young crabs caught wild at river mouths. Output peaked at 1,241 tonnes in 1991 and had fallen to 6 tonnes by 2019, and about nine-tenths of supply is now imported. The Fisheries Research Institute began developing new farming methods in 2015, mastered artificial breeding in 2019 and has since raised its first batch of hatchery-bred adult crabs. It has passed the technique on to private firms.
How it is made
Steaming is the usual treatment, as it keeps the crab's own flavour. Crabs are also cooked with ginger and spring onion, chopped and stir-fried, or set on glutinous rice. Virgin crabs are fairly small, mostly six to eight taels (兩), about 225 to 300 grams, and few pass twelve. The top grade, the double-shell crab (雙殼蟹), has a new shell already formed beneath the old one.
How to eat it
Mud crab is shared at seafood restaurants and banquets, eaten by hand and dipped in ginger and vinegar. Ask for a virgin crab for soft, creamy roe, a red crab for firmer roe, or a male for the meat. Diners who cannot get hairy crab (大閘蟹) often turn to virgin crab roe instead. Autumn is reckoned the best season for crab.
Around Taiwan
- Tainan
- Tucheng Seafood, a short walk from the Luermen Matsu temple in Annan District, is known for steamed virgin mud crab with creamy roe. Mature crabs carrying eggs have firmer flesh.
- South
- The coast south of Chiayi suits the crab best. The Fisheries Research Institute has worked with several farms and a producer group in Qigu (七股), Tainan, on its hatchery-bred stock.
