Marine mammals : hearings before the Subcommittee on Fisheries and Wildlife Conservation of the Committee on Merchant Marine and Fisheries, House of Representatives, Ninety-second Congress--first session on H.R. 690, H.R. 4370, H.R. 4733, H.R. 6554, H.R. 6558, H.R. 6801, H.R. 6804, H.R. 7217, H.R. 7229, H.R. 7431, H.R. 7463, H.R. 7477, H.R. 7530, H.R. 7555, H.R. 7556, H.R. 7638, H.R. 7706, H.R. 7794, H.R. 7861, H.R. 7891, H.R. 7952, H.R. 8105, H.R. 8183, H.R. 8255, H.R. 8391, H.R. 8526, H.R. 8804, H.R. 9041, H.R. 9356, H.R. 9409, H.R. 9557, H.R. 9917, H.R. 10420, H.R. 10569, H.R. 10803, H.R. 10814, H. Con. Res. 77, and H. Con. Res. 173, legislation for the preservation and protection of marine mammals, September 9, 13, 17, 23, 1971