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Federal Register / Vol. 86, No. 106 / Friday, June 4, 2021 / Notices
in stages until the full complement of an arrays airguns are active. Each stage should be approximately the same duration, and the total duration should not be less than approximately 20
minutes. The intent of pre-start clearance observation 30 minutes is to ensure no protected species are observed within the pre-clearance zone or extended EZ, for beaked whales prior to the beginning of ramp-up.
During pre-start clearance period is the only time observations of marine mammals in the buffer zone would prevent operations i.e., the beginning of ramp-up. The intent of ramp-up is to warn marine mammals of pending seismic operations and to allow sufficient time for those animals to leave the immediate vicinity. A ramp-up procedure, involving a step-wise increase in the number of airguns firing and total array volume until all operational airguns are activated and the full volume is achieved, is required at all times as part of the activation of the acoustic source. All operators must adhere to the following pre-start clearance and ramp-up requirements:
The operator must notify a designated PSO of the planned start of ramp-up as agreed upon with the lead PSO; the notification time should not be less than 60 minutes prior to the planned ramp-up in order to allow the PSOs time to monitor the pre-start clearance zone and extended EZ for 30
minutes prior to the initiation of rampup pre-start clearance;
Ramp-ups shall be scheduled so as to minimize the time spent with the source activated prior to reaching the designated run-in;
One of the PSOs conducting prestart clearance observations must be notified again immediately prior to initiating ramp-up procedures and the operator must receive confirmation from the PSO to proceed;
Ramp-up may not be initiated if any marine mammal is within the applicable exclusion or buffer zone. If a marine mammal is observed within the pre-start clearance zone or extended EZ, for beaked whales during the 30 minute pre-start clearance period, ramp-up may not begin until the animals has been observed exiting the zones or until an additional time period has elapsed with no further sightings 15 minutes for small odontocetes and pinnipeds, and 30 minutes for all mysticetes and all other odontocetes, including sperm whales, beaked whales, and large delphinids, such as killer whales;
Ramp-up shall begin by activating a single airgun of the smallest volume in the array and shall continue in stages by doubling the number of active elements
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at the commencement of each stage, with each stage of approximately the same duration. Duration shall not be less than 20 minutes. The operator must provide information to the PSO
documenting that appropriate procedures were followed;
PSOs must monitor the pre-start clearance zone and extended EZ
during ramp-up, and ramp-up must cease and the source must be shut down upon detection of a marine mammal within the applicable zone. Once rampup has begun, detections of marine mammals within the buffer zone do not require shutdown, but such observation shall be communicated to the operator to prepare for the potential shutdown;
Ramp-up may occur at times of poor visibility, including nighttime, if appropriate acoustic monitoring has occurred with no detections in the 30
minutes prior to beginning ramp-up.
Acoustic source activation may only occur at times of poor visibility where operational planning cannot reasonably avoid such circumstances;
If the acoustic source is shut down for brief periods i.e., less than 30
minutes for reasons other than that described for shutdown e.g., mechanical difficulty, it may be activated again without ramp-up if PSOs have maintained constant visual and/or acoustic observation and no visual or acoustic detections of marine mammals have occurred within the applicable EZ.
For any longer shutdown, pre-start clearance observation and ramp-up are required. For any shutdown at night or in periods of poor visibility e.g., BSS 4
or greater, ramp-up is required, but if the shutdown period was brief and constant observation was maintained, pre-start clearance watch of 30 minutes is not required; and Testing of the acoustic source involving all elements requires rampup. Testing limited to individual source elements or strings does not require ramp-up but does require pre-start clearance of 30 min.
Shutdown The shutdown of an airgun array requires the immediate de-activation of all individual airgun elements of the array. Any PSO on duty will have the authority to delay the start of survey operations or to call for shutdown of the acoustic source if a marine mammal is detected within the applicable EZ. The operator must also establish and maintain clear lines of communication directly between PSOs on duty and crew controlling the acoustic source to ensure that shutdown commands are conveyed swiftly while allowing PSOs to maintain watch. When both visual
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and acoustic PSOs are on duty, all detections will be immediately communicated to the remainder of the on-duty PSO team for potential verification of visual observations by the acoustic PSO or of acoustic detections by visual PSOs. When the airgun array is active i.e., anytime one or more airguns is active, including during ramp-up and 1 a marine mammal appears within or enters the applicable EZ and/or 2 a marine mammal other than delphinids, see below is detected acoustically and localized within the applicable EZ, the acoustic source will be shut down. When shutdown is called for by a PSO, the acoustic source will be immediately deactivated and any dispute resolved only following deactivation. Additionally, shutdown will occur whenever PAM alone without visual sighting, confirms presence of marine mammals in the EZ. If the acoustic PSO cannot confirm presence within the EZ, visual PSOs will be notified but shutdown is not required.
Following a shutdown, airgun activity would not resume until the marine mammal has cleared the EZ. The animal would be considered to have cleared the EZ if it is visually observed to have departed the EZ i.e., animal is not required to fully exit the buffer zone where applicable, or it has not been seen within the EZ for 15 minutes for small odontocetes and pinnipeds, or 30
minutes for all mysticetes and all other odontocetes, including sperm whales, beaked whales, and large delphinids, such as killer whales.
The shutdown requirement can be waived for small dolphins if an individual is detected within the EZ. As defined here, the small dolphin group is intended to encompass those members of the Family Delphinidae most likely to voluntarily approach the source vessel for purposes of interacting with the vessel and/or airgun array e.g., bow riding. This exception to the shutdown requirement applies solely to specific genera of small dolphins Lagenorhynchus and Lissodelphis.
We include this small dolphin exception because shutdown requirements for small dolphins under all circumstances represent practicability concerns without likely commensurate benefits for the animals in question. Small dolphins are generally the most commonly observed marine mammals in the specific geographic region and would typically be the only marine mammals likely to intentionally approach the vessel. As described above, auditory injury is extremely unlikely to occur for midfrequency cetaceans e.g., delphinids,
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