(a) The activity identified in §217.80(a) must be conducted in a manner that minimizes, to the greatest extent practicable, adverse impacts on marine mammals and their habitats. When conducting operations identified in §217.80(a), the mitigation measures contained in the Letter of Authorization issued under §§216.106 of this chapter and 217.87 must be implemented. These mitigation measures include (but are not limited to):

(1) Underwater detonations using timed delay devices will only be conducted during daylight hours. The time of detonation shall be limited to an hour after sunrise and an hour before sunset.

(2) NEODS missions shall be postponed if:

(i) The Beaufort sea state is greater than scale number three. Such a delay would maximize detection of marine mammals.

(ii) Large concentrations of fish, jellyfish, and/or large Sargassum rafts are observed within the mitigation-monitoring zone. The delay would continue until the fish, jellyfish, and/or Sargassum rafts that cause the postponement are confirmed to be outside the mitigation-monitoring zone.

(3) Time delays longer than 10 minutes will not be used. Initiation of the timer device will not start until the mitigation-monitoring zone is clear of marine mammals for 30 minutes.

(4) A calculated mitigation-monitoring zone will be established around each underwater detonation location based on charge weight and length of time-delay used. When conducting surveys within the mitigation-monitoring zone radius (but always outside the detonation plume radius/human safety zone) and travel in a circular pattern around the detonation point, surveying the inner (toward the detonation site) and outer (away from the detonation site) areas. For a survey radius of 914.4 meters, the boat will be positioned at 457.2 meters from the detonation point. Similarly, for a survey radius of 1,280.2 meters, boats will be positioned at 640.1 meter distance.

(5) For a survey radius of 914.4 meters, two boats are required. For a radius of 1,280.2 meters, either three boats or two boats/one helicopter are required.

(6) When using two boats, each boat will be positioned on opposite sides of the detonation location, separated by 180 degrees. When using three boats, each boat will be separated by 120 degrees (equidistant from each other).

(7) Two observers in each boat will conduct continuous visual surveys of the mitigation-monitoring zone for the entire duration of the training event, including at least 30 minutes prior to detonation. Observers will search the mitigation-monitoring zone for the presence of marine mammals, and other marine species such as sea turtles, diving birds, large concentrations of fish or jellyfish, and large Sargassum mats. The presence of diving birds, fish, jellyfish, and Sargassum may indicate an increased likelihood of dolphin presence.

(8) To the extent practicable, boats will maintain 18.5 kilometer per hour search speed. This search speed is expected to ensure adequate coverage of the buffer zone. While weather conditions and sea state may require slower speeds in some instances, 18.5 kilometers per hour is considered a prudent, safe, and executable speed that will allow adequate surveillance. For a 914.4 meter survey zone, a boat traveling at 18.5 kilometers per hour and 457.2 meters from the detonation point would circle the point approximately 3.2 times during a 30 minute survey period. By using two boats, approximately 6.4 circles would be completed in total. Similarly, for a 1,280.2 meter radius, each boat would circle the detonation point approximately 2.3 times within 30 minutes, and use of three boats would result in 6.9 total circles.

(9) If available, a U.S. Navy helicopter can be used in lieu of one of the survey boats, so long as safety of flight is not jeopardized. U.S. Navy helicopter pilots are trained to conduct searches for relatively small objects in the water, such as a missing person. A helicopter search pattern is dictated by standard U.S. Navy protocols and accounts for multiple variables, such as size and shape of the search area, size of the object, and environmental conditions, among others.

(10) The mitigation-monitoring zone will be surveyed for 30 minutes prior to detonation and continue for 30 minutes after detonation (concentrated on the area down current of the test site), in order to monitor for marine mammals and other protected species. It is the U.S. Air Force's (on behalf of the U.S. Navy) intent to conduct five successive detonations with a maximum time of 20 minutes between detonations, although a variety of factors can cause a delay of longer than 20 minutes between detonations, although a variety of factors can cause a delay of longer than 20 minutes, including a delay until the following day. Monitoring would continue during the 20 minutes time between detonations, and would serve as both post-detonation monitoring as well as pre-mission monitoring for the next detonation. If the time between detonations is delayed beyond 20 minutes, post-mission monitoring will be conducted for 30 minutes. At the conclusion of the final detonation, post-monitoring will be conducted for 30 minutes.

(11) Other personnel besides designated observers shall also maintain situational awareness of the presence of marine mammals within the mitigation-monitoring zone to the extent practicable given dive safety considerations.

(12) Divers placing the charges on mines will observe the immediate underwater area around the detonation site for marine mammals and other marine species such as diving birds, sea turtles, and Gulf sturgeon, and report sightings to surface observers.

(13) If a marine mammal is sighted within an established mitigation-monitoring zone or moving towards it, underwater detonation events will be postponed or suspended until the marine mammal that caused the postponement/suspension of training operations has voluntarily left the area and the area is clear of marine mammals for at least 30 minutes.

(14) If a marine mammal is detected within or about to enter an established mitigation-monitoring zone and subsequently cannot be reacquired, the mission will be postponed or suspended until the last verified location is outside the mitigation-monitoring zone, the animals is moving away from the area, and the area is clear of marine mammals for at least 30 minutes.

(15) Any marine mammal observed after an underwater detonation either injured or exhibiting signs of distress will be reported to Eglin Air Force Base. Eglin Air Force Base will coordinate with other members of marine mammal stranding networks, as appropriate, and report these events to NMFS or U.S. Fish and Wildlife Service. The report will contain date and time of sighting, location, species description, and indications of the animal's status.

(16) Training operations shall be suspended if the conditions of §217.83(a)-(d) regarding the injury, serious injury, or death of a marine mammal during NEODS training operations are met.

(17) Additional mitigation measures as contained in a Letter of Authorization.

(b) [Reserved]