What must be done during processing to avoid the monkfish meat shrinking and turning tough when cooked?

The thick, gelatinous blue-gray membrane covering the meat must be removed.

Proper preparation of monkfish extends beyond simply cooking it thoroughly; specific structural components of the raw meat must be addressed to ensure desirable texture post-cooking. The raw meat is naturally encased in a distinctive blue-gray membrane layer. This layer is described as thick and gelatinous. If this layer is inadvertently left intact when the fish is cooked, it exhibits a tendency to shrink significantly. This shrinkage directly forces the muscle fibers of the meat to curl inwards, resulting in a final product that is notably tough and unpleasant to eat. Therefore, removing this specific membrane is a necessary, albeit labor-intensive, step in preparation.