【Reading】いしがきだい

【English Name】Spotted Knifejaw

Ishigaki-dai (spotted knifejaw) is a saltwater fish classified in the family Oplegnathidae, with the scientific name Oplegnathus punctatus. Blackish-brown spots are scattered over its grayish-white body surface, and the pattern is said to have given rise to the Japanese name because it evokes a stone wall (ishigaki).

Its body is a laterally compressed disc shape, and it has a beak-like jaw formed by fused teeth. The total length of a typical adult is around 50 cm, but records exceeding 90 cm also exist. It is distributed south of the Boso Peninsula on the Pacific side and south of Yamaguchi Prefecture on the Sea of Japan side, with habitation also reported from the southern Korean Peninsula to the South China Sea and even Hawaii. It tends to prefer warmer waters than the striped beakfish (ishi-dai).

As a sushi topping it is classified as white-fleshed fish, served as nigiri, sashimi, arai, and so on. The best-tasting individuals are said to be those up to around 40 cm, and care is needed in handling large fish because of the risk of ciguatera poisoning.

Aged males lose the markings on their bodies and the area around the mouth whitens, so they are called "kuchijiro" (white mouth). It is also known as a popular target for lure and surf fishing on rocky shores, and natural hybrids with the striped beakfish have been reported. In 1970, artificial crossbreeding succeeded at Kindai University, and the hybrid is also called "kindai."