Spisula sachalinensis (Japanese common name: Ubagai ウバガイ or Hokkigai ホッキ貝, 北寄貝) is a species of edible saltwater clam, a marine bivalve mollusk in the family Mactridae, the surf clams or trough clams. It is commonly referred to as "surf clam." This species is commercially exploited. This clam is widely used for sushi in Japan. The species is found in Tomakomai, Hokkaido and numerous other areas.