Shishamo, known to scientists as Spirinchus lanceolatus and to Japanese consumers as willow leaf fish because of its shape, is a variety of smelt native to Japanese waters. They spawn in shallow waters along the shore in significant numbers, and can be harvested easily during their spawning run. Like other smelt, shishamo is a moderately oily fish filled with healthy omega-3 oils. A similar species, the caplin or capelin harvested in the Canadian provinces of Newfoundland and Quebec, is also sold as shishamo in both Japanese and U.S. markets. In either case, the fish are grilled and eaten whole. Females containing roe are especially prized.
Rinse the shishamo under cold running water, and pat them dry with clean paper towels.
Preheat a gas or charcoal grill to about 400 degrees Fahrenheit. Season the shishamo with salt and pepper.
Lay the shishamo directly on the grill, if you wish, or enclose them in a fish-grilling basket for convenience. The fish are oily enough not to stick badly, but they are small and fragile and can easily be broken.
Grill for three to four minutes on each side, and serve hot as part of a Japanese-themed meal.
Shishamo can be eaten whole from head to tail, and often are. If you are squeamish about this, the head can be easily separated after cooking. Ponzu or other dipping sauces make a pleasant accompaniment.