50 C.F.R. § 218.233
Prohibitions
Except incidental take described in § 218.232 and authorized by an LOA issued under § 216.106 of this chapter and this subpart, it shall be unlawful for any person to do the following in connection with the activities described in this subpart:
(a) Violate, or fail to comply with, the terms, conditions, and requirements of this subpart or an LOA issued under § 216.106 of this chapter and this subpart;
(b) Take any marine mammal not specified in § 218.232(b);
(c) Take any marine mammal specified in § 218.232(b) in any manner other than as specified in the LOA;
(d) Take a marine mammal specified in § 218.232(b) after NMFS determines such taking results in more than a negligible impact on the species or stock of such marine mammal; or
(e) Take a marine mammal specified in § 218.232(b) after NMFS determines such taking is having, or may have, an unmitigable adverse impact on the availability of the species or stock for taking for subsistence uses.