Tuna-porpoise : hearings before the Committee on Merchant Marine and Fisheries, House of Representatives, Ninety-fifth Congress, first session on reducing porpoise mortality, H.R. 6146, H.R. 6729, H.R. 6807, H.R. 6907, H.R. 6928, and H.R. 6970, these bills amend the Marine Mammal Protection Act of 1972 with respect to the taking of marine mammals incidental to the course of commercial fishing operations, May 13 and 16, Tuna-Porpoise Oversight, August 1, 1977. (U.S. Govt. Print. Off, 1977)