Naturally attached, as it is used to describe shark fins, refers to shark fins that remain attached to the shark carcass via at least some portion of uncut skin. As used to describe the head of a swordfish, naturally attached refers to the whole head remaining fully attached to the carcass except for the bill, which may be removed provided it has been removed forward of the anterior tip of the lower jaw.
50 CFR § 635.2
In addition to the definitions in the Magnuson-Stevens Act, ATCA, and 600.10 of this chapter, the terms used in this part have following meanings. If applicable, the terms used in this part supercede those used in 600.10: