50 C.F.R. § 216.156 Letter of Authorization.
Title 50 - Wildlife and Fisheries
(a) A Letter of Authorization, unless suspended or revoked, will be valid for a period of time specified in the Letter of Authorization but may not exceed the period of validity of this subpart. (b) A Letter of Authorization with a period of validity less than the period of validity of this subpart may be renewed subject to renewal conditions in §216.157. (c) A Letter of Authorization will set forth: (1) Permissible methods of incidental taking; (2) Specified geographic area for taking; (3) Means of effecting the least practicable adverse impact on the species of marine mammals authorized for taking and its habitat; and (4) Requirements for monitoring and reporting incidental takes. (d) Issuance of a Letter of Authorization will be based on a determination that the number of marine mammals taken by the activity will be small, and that the level of taking will be consistent with the findings made for the total taking allowable under these regulations. (e) Notice of issuance or denial of a Letter of Authorization will be published in the
Title 50: Wildlife and Fisheries
PART 216—REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE MAMMALS
Subpart N—Taking of Marine Mammals Incidental to Missile Launch Operations from San Nicolas Island, CA
§ 216.156 Letter of Authorization.

