Section 600.1203 - Prohibitions(a) It is unlawful for any person to do, or attempt to do, any of the following:(2) To have custody, control, or possession of a fin, aboard a fishing vessel, unless the fin is naturally attached.(3) Transfer a fin from one vessel to another vessel at sea unless the fin is naturally attached.(4) Receive a fin in a transfer from one vessel to another vessel at sea unless the fin is naturally attached.(5) Land a fin unless the fin is naturally attached.(6) Land a shark carcass without all of its fins naturally attached.(7) Possess, purchase, offer to sell, or sell fins or shark carcasses taken, transferred, landed, or possessed in violation of this section.(8) When requested, fail to allow an authorized officer or any employee of NMFS designated by a Regional Administrator, or by the Director of the Office of Sustainable Fisheries in the case of the Atlantic Highly Migratory Species, access to or inspection or copying of any records pertaining to the landing, sale, transfer, purchase, or other disposition of fins or shark carcasses.(b) For purposes of this section, it is a rebuttable presumption that:(1) If a fin is found aboard a vessel, other than a fishing vessel, without being naturally attached, such fin was transferred in violation of this section.(2) If, after landing, the total weight of fins landed from any vessel exceeds five percent of the total weight of shark carcasses landed, such fins were taken, held, or landed in violation of this section.