• The Supplemental EIS/OEIS is an update to the 2011 GOA Navy Training Activities Final EIS/OEIS and the 2016 GOA Navy Training Activities Final Supplemental EIS/OEIS. 
• The purpose of this Supplemental EIS/OEIS is to update the 2011 and 2016 impact analyses with new information and analytical methods. New information includes an updated acoustic effects model, updated marine species density data and hearing criteria, and other emergent best available science.
• The Navy prepared a Supplemental EIS/OEIS in support of the renewal of federal regulatory permits and authorizations under the Marine Mammal Protection Act and the Endangered Species Act. Current federal regulatory permits and authorizations expired in April 2022.
• The Supplemental EIS/OEIS supports naval training requirements to achieve and maintain fleet readiness as required by Title 10 of the U.S. Code.

• Since the release of the 2020 Draft Supplemental EIS/OEIS on Dec. 11, 2020, and completion of the Northern Edge 2021 exercise, the Navy recognized that the size and shape of the Gulf of Alaska Temporary Maritime Activities Area no longer provides sufficient space for the realistic maneuvering of vessels and aircraft during training exercises. Changes to the Gulf of Alaska Study Area include additional airspace and sea space to the west and south of the Temporary Maritime Activities Area. The additional area is referred to as the Western Maneuver Area and adds approximately 185,806 square nautical miles to the Study Area. This additional space enables Navy personnel and units to practice more realistic, complex training scenarios in a safer, more efficient manner that will better prepare them to respond to real-world incidents.
• The Temporary Maritime Activities Area (approximately 42,146 square nautical miles) remains unchanged and any activities involving active sonar or explosives will, as in the past, occur in this area only. The Navy did not propose new or increased number of training activities in the Western Maneuver Area, only an expansion of the area the Navy may use for vessel and aircraft maneuvering purposes during exercises.
• Given this change to the Proposed Action, the Navy determined that preparation of a Supplement to the 2020 Draft Supplemental EIS/OEIS was warranted.

• While the revised Gulf of Alaska Study Area is larger than the area described in the 2020 Draft Supplemental EIS/OEIS, the Navy did not propose new or increased number of training activities in the Western Maneuver Area, only an expansion of the area the Navy may use for vessel and aircraft maneuvering purposes during exercises. The activities conducted in the Western Maneuver Area are limited to vessel movements and aircraft training, and several events associated with these movements. The number of vessels, aircraft, underway steaming hours, events, and flight times remains the same. The vast majority of training activities will still occur only in the Gulf of Alaska Temporary Maritime Activities Area. The Navy will not use sonar or explosives in the Western Maneuver Area; any activities involving active sonar or explosives will, as in the past, occur in the Temporary Maritime Activities Area only. The Temporary Maritime Activities Area is unchanged from the 2011 GOA Final EIS/OEIS and the 2016 GOA Supplemental EIS/OEIS. 

• Training activities to occur in the Western Maneuver Area include Air Combat Maneuver, Air Defense Exercise, Maritime Interdiction, Sea Surface Control, Electronic Warfare Exercise, Surface-to-Surface Gunnery Exercise (non-explosive practice munitions only), and Deck Landing Qualification. The use of sonar or explosives will not occur in the Western Maneuver Area.

• Changes to the Study Area include additional airspace and sea space, called the Western Maneuver Area, to the west and south of the Gulf of Alaska Temporary Maritime Activities Area for vessel and aircraft maneuvering. The Western Maneuver Area is approximately 185,806 square nautical miles.

• In direct response to agency, tribal, and public comments, the Navy will implement a new mitigation area within the continental shelf and slope area of the Gulf of Alaska Temporary Maritime Activities Area. The Navy will expand its mitigation measures for explosives detonated at or near the surface and prohibit the use of explosives during training (up to 10,000 feet altitude) in areas of less than 4,000 meter depth to protect marine species and biologically important habitat. The Navy anticipates the implementation of the mitigation area will reduce impacts on marine mammals, fishes (including salmon), and marine birds. These mitigations are further described in the Supplement and the Final Supplemental EIS/OEIS.

• Yes. The Navy will continue periodic military training activities, which include the continued use of active sonar only in the Temporary Maritime Activities Area. The Navy will not use sonar in the Western Maneuver Area. The Navy will continue to implement mitigation measures to avoid or reduce potential impacts on marine species and the environment from training activities.
• For decades, the Navy has used various types of passive and active sonar while training in the Gulf of Alaska, and has analyzed those activities in previous environmental impact analyses. The Navy reanalyzed the potential environmental effects of sonar use in the Temporary Maritime Activities Area in the 2020 Draft Supplemental EIS/OEIS and the 2022 Final Supplemental EIS/OEIS.

• While exact causes of strandings, when a marine species is aground on the shore, are uncertain, scientists have identified potential contributing factors for strandings including age, illness, or disease; parasites; pollution, including ingestion of marine debris and plastics; contaminant load; unusual oceanographic or weather events; trauma; starvation; and ship strikes. Some stranding incidents have been coincident to Navy training with sonar and weapon systems, which is of great concern to the Navy. 
• Since 2006, scientific monitoring has found no evidence of strandings resulting from the use of sonar in any U.S. Navy range complex training area. However, sonar use during exercises involving the U.S. Navy (most often in association with other nations' defense forces) has been identified as a contributing cause or factor in five specific mass stranding events: Greece in 1996; the Bahamas in March 2000; Madeira Island, Portugal in 2000; the Canary Islands in 2002; and Spain in 2006. The factors leading to these strandings are not understood, although various research projects have been underway to better understand these rare occurrences. 
• Through the Marine Mammal Protection Act and Endangered Species Act permitting processes, the Navy updates marine mammal Stranding Response Plans in coordination with NMFS, as needed. The Stranding Response Plan specifies the Navy’s requirements for reporting marine mammal strandings and assisting with post stranding data collection in association with major training exercises.

To learn more about marine mammals, sonar, sound in the water, and the Navy’s ocean stewardship programs, visit:

• The Navy’s Marine Species Monitoring webpage
• The Navy’s Stewards of the Sea Environmental Outreach Program webpage
• The Discovery of Sound in the Sea website

• Sailors must train in a variety of high-stress environments, including scenarios that involve the use of and exposure to explosive ordnance, to be ready to respond to emergencies and national security threats.
• Sailors train using non-explosive munitions as often as possible. However, non-explosives cannot completely replace training in a live environment. Limited training with explosives occurs only in established operating areas. The Navy ensures public safety by establishing safety buffers around activity sites when in use. The Navy, in coordination with the U.S. Coast Guard and Federal Aviation Administration, issues notices to mariners and pilots to ensure public safety.

• Sailors train using non-explosive munitions as often as possible. However, non-explosives cannot completely replace at-sea training in a live environment.
• Training at sea with explosives significantly enhances the safety of U.S. forces in combat and improves readiness and equipment reliability.
• Sailors must train in a variety of high-stress environments, including scenarios that involve the use of and exposure to explosive ordnance, to be ready to respond to emergencies and national security threats.
• Training at sea with explosives is limited, occurs only in established operating areas, and only after the Navy, in coordination with the Coast Guard and Federal Aviation Administration, issues notices to mariners and pilots to ensure public safety. 

• Since 2011, the Navy has monitored and observed marine mammals during Navy training activities in the Gulf of Alaska. Some of these efforts include:
  • Collecting passive acoustic data using an unmanned glider.
  • Maintaining, collecting, and analyzing data from multiple passive acoustic monitoring sites. Data from these sites are used for characterizing ambient sound levels and detecting the presence of vocalizing marine species.
  • Surveying for cetacean abundance and distribution in the Study Area using line transect surveys.
• Between 2009 and 2021, the Navy has funded approximately $6 million for marine species research, surveys, and monitoring efforts within the offshore waters of the Gulf of Alaska.
• For more information, please visit the Navy’s Marine Species Monitoring webpage.

• The Navy has committed approximately $250 million over the past decade to marine mammal and sound in water research. In 2019, the Navy funded $20 million in marine species research and monitoring projects around the world. Between 2009 and 2020, the Navy has funded approximately $6 million for marine species research, surveys, and monitoring efforts in the Gulf of Alaska. This research has generated more than 800 open-source publications.
• The Navy funds research to:
  • Detect and track marine mammals.
  • Understand marine mammal behavioral responses to sound. 
  • Establish hearing thresholds; determine species location and abundance.
  • Mitigate the effects of sound to assist environmental planners, range operators, regulatory agencies, and other stakeholders in making informed decisions as part of the permitting process for Navy at-sea training activities. 
• Data and reports from scientific research and monitoring help environmental regulators, scientists, and the Navy to:
  • Better understand the abundance, distribution, foraging, reproduction, physiology, hearing and sound production, behavior, and ecology of marine species, which is needed to assess the effects on species from naval activities. Assess behavioral responses of marine species to sonar and explosives.
  • Develop and improve models to better predict potential effects of underwater sound and explosives on marine species.
  • Develop effective protective measures.
• As the vast majority of these activities take place on ranges, the Navy commits significant funding and manpower to improve understanding of the behavior and abundance of marine mammals within and in near proximity to these areas. 

• In the 2020 Draft Supplemental EIS/OEIS and 2022 Final Supplemental EIS/OEIS, the Navy updated previous analyses of potential impacts with relevant new information and best available science. The Navy evaluated each resource area in the 2011 and 2016 impact analyses to determine the need for reanalysis. For the majority of the resource areas, results remain unchanged and did not require additional analysis. 
• The Navy determined that new research, literature, laws, and regulatory guidance addressed in this Supplemental EIS/OEIS resulted in little or no change to the findings of the impact analyses in the 2011 GOA Final EIS/OEIS and the 2016 GOA Final Supplemental EIS/OEIS, and following resource areas were not carried forward for detailed reanalysis:
  • Air Quality
  • Sediments and Water Quality
  • Marine Habitats
  • Marine Vegetation
  • Marine Invertebrates
  • Cultural Resources
  • Public Health and Safety
• The following resource areas were carried forward for detailed reanalysis:
  • Fishes
  • Sea Turtles
  • Marine Mammals
  • Birds
  • Socioeconomic Resources and Environmental Justice

• It is important to the Navy to avoid or minimize impacts on the marine environment from at-sea training activities. The Navy employs standard operating procedures and protective measures during sonar use as well as additional event-specific mitigation measures. 

• Yes. The Navy considered implementing geographic and seasonal mitigation measures where biologically appropriate and practicable without compromising the effectiveness of at-sea training or personnel safety. However, the Navy needs to continue to train in diverse environments, many of which replicate operational environments around the world. It is essential to military readiness that the Navy maintains this flexibility. The Navy worked with NMFS on developing final mitigations during the consultation processes.
• Examples of geographic and seasonal mitigation measures include:
  • North Pacific Right Whale Mitigation Area
  • Portlock Bank Mitigation Area 

• No. The Navy does not restrict civilian navigation, including fishing vessels, commercial shipping, or aircraft, during Northern Edge maritime activities. 
• The Navy, in coordination with the Coast Guard and Federal Aviation Administration, issues notices to mariners and aviators to minimize inconveniences whenever possible, while ensuring safety at all times.
• Ensuring public access to natural resources is important to the Navy. Sailors share the ocean, coastal areas, and airspace with the community and recognize the importance of public access. 
• The Navy trains in a manner that is compatible with civilian activities at sea and in the air. The Navy is committed to providing continued access to surface water space and airspace above the Gulf of Alaska.
• The Navy understands that general aviation is an important part of Alaska’s economy. Light-aircraft pilots transport residents, tourists, supplies, and mail throughout much of Alaska that would otherwise be inaccessible. The Navy acknowledges the importance and necessity for pilots to be able to fly throughout Alaska and surrounding areas with as few impediments as possible.

• No. The Navy does not restrict civilian navigation, including fishing vessels, commercial shipping, or aircraft, during Northern Edge maritime activities. The Navy is not making any changes to access to fishing areas; the access available now will remain the same.
• It is not the Navy’s intent to restrict public access; however, the safety of Navy Sailors and the public is of utmost importance. 
• Navy personnel share the ocean and coastal areas with the community and recognize the importance of public access. The Navy strives to be a good neighbor by maintaining access to public areas whenever possible and ensuring safety at all times.
• When areas are scheduled for Navy use, the Navy coordinates with the Coast Guard and Federal Aviation Administration to publish notices to help the public plan accordingly. Appropriate local agencies are notified. 

• The Office of the Assistant Secretary of the Navy for Energy, Installations, and Environment, which is responsible for all environmental and natural resource issues, is the decision-maker regarding the selection and implementation of an alternative. The decision is based on many factors, including the details of the Navy’s environmental impact analyses, breadth of public comment, recommendations from Navy commands, and mission requirements.

• The NMFS Headquarters Office served as a cooperating agency on this Supplemental EIS/OEIS. The Navy coordinated with the NMFS Headquarters Office, the NMFS Alaska regional office, and the Alaska regional office of the U.S. Fish and Wildlife Service under the Marine Mammal Protection Act and the Endangered Species Act.
• Other federal and state regulatory agencies, such as the Environmental Protection Agency, Federal Aviation Administration, Alaska Department of Natural Resources, and Alaska Department of Fish and Game Division of Wildlife Conservation, were invited to comment on the environmental analysis.
• Federal and state regulators reviewed the Supplemental EIS/OEIS and the Navy’s consultation packages to include Biological Assessments.