Section 100C. No person shall take, or attempt to take, with or by the use of a net, seine or any other contrivance of any kind or description, except by hook and line, any shad within the jurisdiction of the commonwealth; provided, that it shall not be a violation of this section for any person to take shad by means of such seine, net or other contrivance, while fishing for other fish for the catching of which the use of such seine, net or other contrivance is permitted, if such shad is immediately returned alive to the waters from which taken.