Arrowtooth flounder

Arrowtooth flounder (Atheresthes stomias) is a flatfish of the north to mid-Pacific that remains relatively under-exploited compared with better-known flatfish. Its flesh is noticeably softer than that of most flatfish because it contains a natural cysteine proteinase, an enzyme that breaks down muscle proteins and weakens texture, which has historically kept its market value low. It is marketed in fillet form and also frozen into blocks for processing into portions. Food technologists have worked on firming its texture with additives and process tweaks, and because the soft flesh is easily damaged, careful chilled handling from catch to processing is needed to keep quality acceptable.