Every permit issued in accordance with the provisions of sections
443 to 448 of this title, which may not be taken up by an inspector
or deputy inspector, shall be returned within four days after
issuance to the office of the supervisor of the harbor; such permit
shall bear an indorsement by the master of the towboat, or the
person acting in such capacity, stating whether the permit has been
used, and, if so, the time and place of dumping. Any person
violating the provisions of this section shall be liable to a fine
of not more than $500 nor less than $100.