Fisheries Development Act - Title I: Authorizes the Secretary of Commerce to establish a Fisheries Extension Service in the Department. Provides that such extension service be coordinated with the fisheries extension activities carried on by the States and by sea grant colleges, with special emphasis on institutional arrangements which promote regional undertakings.

Sets forth criteria for the determination of priorities under which industries and geographic areas are to receive aid to initiate such extension activities. Establishes such criteria as the size of the industries to be affected, the relative state of their technology, and the extent of potential resources and markets. Specifies that fishery extension work which the Secretary is authorized to carry out shall consist of giving instructions in commercial fishing, in processing and marketing of fishery products, and in business management.

Authorizes specific appropriations for fiscal years 1975-1977.

Title II: Authorizes technical assistance to fishery cooperatives, marketing associations, and other private agencies or organizations.

Authorizes the Secretary to make grants to assist the U.S. fishing industry to convert fishing vessels to expand into unexploited or underexploited species.

Directs the Secretary to undertake a comprehensive study and review of existing fisheries regulations on Federal, State, and local levels including the importation of fish. Provides conditionally for the exemption from the antitrust laws of voluntary associations of handlers of fish and fish products. Sets forth criminal penalties for violations of this Act.