50 C.F.R. § 216.103
In addition to definitions contained in the MMPA, and in § 216.3 , and unless the context otherwise requires, in subsequent subparts to this part:
Arctic waters means the marine and estuarine waters north of 60° N. lat.
Citizens of the United States and U.S. citizens mean individual U.S. citizens or any corporation or similar entity if it is organized under the laws of the United States or any governmental unit defined in 16 U.S.C. 1362(13) . U.S. Federal, state and local government agencies shall also constitute citizens of the United States for purposes of this part.
Incidental harassment, incidental taking and incidental, but not intentional, taking all mean an accidental taking. This does not mean that the taking is unexpected, but rather it includes those takings that are infrequent, unavoidable or accidental. (A complete definition of "take" is contained in § 216.3 ).
Negligible impact is an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.
Small numbers means a portion of a marine mammal species or stock whose taking would have a negligible impact on that species or stock.
Specified activity means any activity, other than commercial fishing, that takes place in a specified geographical region and potentially involves the taking of small numbers of marine mammals.
Specified geographical region means an area within which a specified activity is conducted and that has certain biogeographic characteristics.
Unmitigable adverse impact means an impact resulting from the specified activity:
50 C.F.R. §216.103