The Secretary may establish reasonable charges and fees and issue permits for public use of national wildlife refuges, game ranges, national fish hatcheries, and other conservation areas administered by the Department of the Interior for fish and wildlife purposes. The Secretary may issue regulations to carry out the purposes of this subchapter. A violation of such regulations shall be a misdemeanor with maximum penalties of imprisonment for not more than six months, or a fine of not more than $500, or both. The provisions of this subchapter and any such regulation shall be enforced by any officer or employee of the United States Fish and Wildlife Service designated by the Secretary of the Interior.