(a) An LOA issued under §§ 216.106 of this chapter and 217.166 for the specified activities may be modified upon request by Hilcorp, provided that:

(1) The changes to the activity or the mitigation, monitoring, or reporting does not change the findings made pursuant to this subpart and do not result in more than a minor change in the total estimated number of takes (or distribution by species or stock or years); and

(2) NMFS determines that Hilcorp implemented the mitigation, monitoring, and reporting measures required by the LOA for which modification is requested.

(b) An LOA issued under §§ 216.106 of this chapter and 217.166 may be modified at NMFS' initiation if:

(1) Doing so creates a reasonable likelihood of more effectively accomplishing the goals of the mitigation and monitoring measures; or

(2) NMFS determines that an emergency exists that poses a significant risk to the well-being of the species or stocks of marine mammals specified in an LOA issued pursuant to §§ 216.106 of this chapter and 217.166, in which case, the LOA may be modified without prior notice or opportunity for public comment; however, notification will be published in the Federal Register within 30 days of the action.

(c) If the modifications to the specified activities, mitigation, monitoring, or reporting measures are substantial, NMFS shall publish a notice of proposed LOA in the Federal Register and solicit public comment prior to making a determination on issuance.

(d) Possible sources of data that could contribute to a decision to modify the LOA include, but are not limited to:

(1) Results from Hilcorp's monitoring;

(2) Results from other marine mammal and/or sound research or studies; and

(3) Any information that reveals marine mammals may have been taken in a manner, extent or number not authorized by this subpart or subsequent LOAs.