What it is
Mullet roe (烏魚子) is a pair of mullet ovaries cured with salt and dried until firm and reddish amber. Its nickname is 烏金, "black gold". It is a costly winter delicacy and a fixture of the Lunar New Year's Eve dinner. Japan makes the same product as karasumi, and Mediterranean bottarga is a close relative.
Where it came from
Mullet fishing in Taiwan goes back at least to Dutch rule in the 17th century, and Han fishermen went on catching the fish through the Qing period. Each winter the mullet swim south from the coast of mainland China to spawn off Taiwan's south-west, and the local season falls around the winter solstice. Fishermen in Qieding (茄萣), Kaohsiung, called them 信魚, "reliable fish", because they turned up every year. Crews there drew fortune slips at the temples of Mazu and the Wangye gods to forecast the catch.
The Japanese name karasumi is written 唐墨, "Chinese ink", because the slabs were thought to look like ink sticks from China. Food writer Lee Nai-hao (李廼澔) dates Taiwan's first roe factory to 1909, when the Japanese brought a specialist from Nagasaki to teach the craft.
Catches have fallen since the 1990s, blamed on years of fishing along the migration route, pollution and warmer seas. Pond farming has spread, and outside the short local season most raw roe is imported from Brazil, the US, Australia and mainland China.
How it is made
Workers open the female fish and lift out the paired ovaries, then rinse away every trace of blood, which would darken the roe as it oxidises. The sacs are rolled or packed in salt for several hours and pressed flat under boards. Once the salt is washed off they are shaped and dried, traditionally in the sun on threshing floors and turned often, now also in climate-controlled rooms. Drying takes from a few days to about a week. Good roe is reddish, slightly translucent and firm enough to leave no fingerprint.
How to eat it
Cooks peel off the thin membrane, wet the roe with rice wine or kaoliang (高粱酒), a sorghum spirit, and grill or pan-fry it briefly. Some set the spirit alight to sear each side. Overcooked roe loses its stickiness and turns grainy. It is cut into thin slices and eaten with raw garlic leaves (蒜苗) and slices of white radish, or lately apple or Asian pear.
Around Taiwan
- Tainan
- With Kaohsiung's waters now often too warm for them, migrating mullet tend to turn back off Jiangjun (將軍) in Tainan and seldom reach the old Qieding grounds to the south.
- Kaohsiung
- Qieding (茄萣) has about a century of mullet fishing, and Xingda Harbour (興達港) once sent out hundreds of mullet fleets. Few boats are left, as warmer water now turns the fish back before they arrive. Dried roe is sold at the harbour's evening fish market.
- Central
- Lukang (鹿港) in Changhua was the site of Taiwan's first roe factory, by Lee Nai-hao's account. Most raw roe is processed in traditional factories in central and southern Taiwan.
- South
- The south-west coast is the mullet's winter spawning ground, so roe caught there tends to be riper than roe from the north. Donggang (東港) in Pingtung is known for processing it.
