The laws provide that the President shall appoint from among the civil officers or employes of the government a Commissioner of Fish and Fisheries, who must be a person of proved scientific and practical acquaintance with the fishes of the sea-coast, and who receives no salary additional to that which he drew before his appointment. It is his business to prosecute investigations and inquiries on the subject, with the view of ascertaining whether any, and what, diminution in the number of the food fishes of the coast and lakes of the United States has taken place, and, if so, to what causes this diminution is due, and, also, whether any, and what, protective, prohibitory, or precautionary measures should be adopted in the premises, and report the same to Congress. He may take, or cause to be taken, at all times, in the waters of the sea coast of the United States, where the tide ebbs and flows, and also in the waters of the lakes, such fish or specimens thereof as may, in his judgment, from time to time, be needful or proper for the conduct of his duties, any law, custom, or usage of any State to the contrary notwithstanding.