This chapter shall not be construed to permit the catching or sale of any fish or other aquatic product which is otherwise prohibited by law from being caught or sold, but shall be supplementary thereto. This chapter is supplementary of and not amendatory or in alteration of any other laws for the accomplishment of any of the purposes herein set forth, and shall apply only to organizations created and operating hereunder. However, associations organized hereunder shall be deemed nonprofit, inasmuch as they are not organized to make profits for themselves, as such, or for their members, as such, but only for their members as producers.