Except as otherwise provided in the Act or these regulations, it is unlawful for:

(a) Any person to use any port, harbor, or other place under the jurisdiction of the United States for any purpose in any way connected with a prohibited taking or any unlawful importation of any marine mammal or marine mammal products;

(b) Any person to possess any marine mammal, or product therefrom, taken in violation of the Act or these regulations;

(c) Any person to transport, purchase, sell, or offer to purchase or sell any marine mammal or marine mammal product; or

(d) Any person subject to the jurisdiction of the United States to use in a commercial fishery, any means or method of fishing in contravention of regulations and limitations issued by the Secretary of Commerce for that fishery to achieve the purposes of this Act.