3. Any person who- (a) fishes in any private waters, not having a right to fish therein, (b) erects, places, maintains or uses any fixed engine in private waters, or puts, or knowingly permits to be put, therein any matter for the purpose of catching or destroying fish without the permission of the person to whom the right of fishery therein belongs; shall be guilty of an offence, and shall be punished for a first offence with a fine not exceeding fifty Taka. and for a subsequent offence with imprisonment which may be simple or rigorous, for a term not exceeding one month or with a fine not exceeding two hundred Taka, or both: Provided that nothing herein contained shall apply to acts done by any person in the exercise of a bona fide claim of right, or shall prevent any person from angling with a rod and line or with a line only in any portion of a navigable river.