No person shall dredge, plant or collect any shells, shellfish or other material or perform any work pertaining to the shellfish industry upon any shellfish grounds, unless each lot whereon any such work is performed has at each corner thereof a buoy visible above mean high water. There shall be on each such buoy the initials of the owner or lessee of such lot and the number of the same as shown on the latest map issued in the report of the Commissioner of Agriculture, and the initial or initials denoting the direction of each corner from the center of the lot printed upon a tag securely fastened to each such buoy. Intermediate line buoys shall be so placed that the distance between buoys shall not be greater than eight hundred feet to be determined by the commissioner, provided said commissioner may permit the use of stakes in lieu of buoys where such use may be found necessary or advisable. Any person who violates any provision of this section shall be fined not more than one hundred dollars.