Defect on dressed fish caused by leaving the entrails in fish too long. A heat is created and deteriorates the cavity wall. A valid reason for rejecting fish. Found often in salmon. When a fish is first caught it is very important that the intestines are removed as soon as possible. If the entrails are left in too long a bacteria begins to grow and when the fish is finally eviscerated there will be brown spot in the cavity. This spot is referred to as "belly burn" and results in an inferior product. It happens frequently in salmon and it is a legitimate reason for rejecting an order.