3.8 Marine Mammals

3.8 Marine Mammals GOA NAVY TRAINING ACTIVITIES FINAL SUPPLEMENTAL EIS/OEIS JULY 2016 3.8 MARINE MAMMALS MARINE MAMMALS SYNOPSIS The United States Department of the Navy previously considered training in the Alaska Training Areas and the Gulf of Alaska for all potential stressors and their potential impacts to marine mammals in the analysis as presented in the 2011 Environmental Impact Statement (EIS)/Overseas EIS (OEIS). Since that document was completed, there have been improvements made in the modeling of potential impacts from acoustic stressors as well as the collection of new marine mammal data, new acoustic impact modeling methods, and new impact thresholds and criteria, which have been incorporated into the analysis presented in this Supplemental EIS/OEIS. This Supplemental EIS/OEIS, therefore, focuses on a re-analysis of potential impacts on marine mammals from acoustic stressors during training in the Temporary Military Activities Area portion of the 2011 GOA Final EIS/OEIS Study Area. Acoustic stressors analyzed in this Supplemental EIS/OEIS are identical to those analyzed in the 2011 GOA Final EIS/OEIS and include the following: Sonar and other active acoustic sources Explosives Proposed Action Summary of Impacts The use of sonar and active acoustic sources and explosives is not expected to result in mortality to marine mammals; In general, long-term consequences for individuals or populations of marine mammals would not be expected. Pursuant to the Marine Mammal Protection Act (MMPA), use of sonar and other active acoustic sources and explosives may result in Level B harassment of certain marine mammals and may result in Level A harassments of Dall’s porpoises. Pursuant to the Endangered Species Act (ESA), sonar and other active sources may affect and are likely to adversely affect certain ESA-listed marine mammals. Pursuant to the ESA, use of explosives may affect and is not likely to adversely affect ESA-listed marine mammals. Acoustic stressors will have no effect on marine mammal critical habitats. 3.8.1 INTRODUCTION This section (3.8, Marine Mammals) of the Supplemental Environmental Impact Statement (EIS)/Overseas EIS (OEIS) provides the analysis of potential impacts to marine mammals that are found in the Gulf of Alaska (GOA) Temporary Maritime Activities Area (TMAA) Study Area (Study Area). The text box above provides a synopsis of the United States (U.S.) Department of Navy’s (Navy’s) determination of potential impacts from the Proposed Action on marine mammals. Section 3.8.2 (Affected Environment) provides an introduction to the species that occur in the Study Area. The complete analysis and summary of potential impacts of the Proposed Action on marine mammals are found in Sections 3.8.3 (Environmental Consequences), 3.8.4 (Summary of Impacts [Combined Impacts of All Stressors] on Marine Mammals), and 3.8.5 (Summary of Observations During Previous Navy Activities), respectively. MARINE MAMMALS 3.8-1 GOA NAVY TRAINING ACTIVITIES FINAL SUPPLEMENTAL EIS/OEIS JULY 2016 Marine mammals are a diverse group of approximately 130 species. Most live predominantly in the marine habitat, although some species (e.g., seals) spend time in terrestrial habitats or, in some cases, in freshwater environments, such as certain freshwater dolphins (Jefferson 2009, Rice 1998). The exact number of formally recognized marine mammal species changes periodically with new scientific understanding or findings (Rice 1998). Even the higher-level classification of marine mammals is controversial because the understanding of their origins and relationships continues to evolve (for a list of current species, see the formal list, Marine Mammal Species and Subspecies, maintained by the Society for Marine Mammalogy [Perrin et al. 2009]). This analysis uses the list of species provided by the National Oceanic and Atmospheric Administration (NOAA)/National Marine Fisheries Service (NMFS) 2015 U.S. Pacific Marine Mammal Stock Assessments (Carretta et al. 2016b) and the 2015 Alaska Marine Mammal Stock Assessments (Muto et al. 2016). All marine mammals in the United States are protected under the Marine Mammal Protection Act (MMPA), and some species receive additional protection under the Endangered Species Act (ESA). The MMPA defines a marine mammal “stock” as “a group of marine mammals of the same species or smaller taxon in a common spatial arrangement that interbreed when mature.” For management purposes under the MMPA, a stock is considered an isolated population or group of individuals within a whole species that is found in the same area. However, generally due to a lack of sufficient information, management stocks defined by NMFS may include groups of multiple species, such as the six species grouped together as the Mesoplodon beaked whales management unit for the Pacific U.S. West Coast region (Carretta et al. 2016b). In other cases, a single species may include multiple stocks recognized for management purposes (e.g., harbor porpoise in Alaska; see Muto et al. 2016). For summaries of the general biology and ecology of marine mammals beyond the scope of this Supplemental EIS/OEIS, see Berta et al. (2006), Hoelzel (2003), Jefferson et al. (2008), Perrin et al. (2008), Reynolds and Rommel (1999), Rice (1998), and Twiss and Reeves (1999). Additional species profiles and information on the biology, life history, species distribution, and conservation of marine mammals also can be found through the following organizations: NMFS Office of Protected Resources (includes species distribution maps) Ocean Biogeographic Information System Spatial Ecological Analysis of Megavertebrate Populations (known as OBIS-SEAMAP) species profiles NOAA Cetacean Density and Distribution Mapping Working Group International Whaling Commission International Union for Conservation of Nature, Cetacean Specialist Group The Marine Mammal Commission Society for Marine Mammalogy Marine mammal survey data in the offshore waters of the Gulf of Alaska are limited, as most survey efforts have been localized and nearshore. Much of what is known about cetacean occurrence has come from whaling records (e.g., Ivashchenko et al. 2012), stranding records, anecdotal sighting reports, and other additional efforts (Davis et al. 2012; Matsuoka et al. 2013). The Navy conducted the first systematic marine mammal survey of waters in the Study Area from 10 to 20 April 2009 (Rone et al. 2009). The survey was conducted using systematic line-transect survey protocol, and both visual and acoustic detection methods were used during the survey (Rone et al. 2009). Eleven marine mammal species were seen and positively identified during the survey, including fin whale (Balaenoptera physalus), humpback whale (Megaptera novaeangliae), gray whale (Eschrichtius robustus), minke whale (Balaenoptera acutorostrata), killer whale (Orcinus orca), Pacific white-sided dolphin (Lagenorhynchus MARINE MAMMALS 3.8-2 GOA NAVY TRAINING ACTIVITIES FINAL SUPPLEMENTAL EIS/OEIS JULY 2016 obliquidens), Dall’s porpoise (Phocoenoides dalli), harbor porpoise (Phocoena phocoena), Steller sea lion (Eumetopias jubatus), harbor seal (Phoca vitulina), and sea otter (Enhydra lutris kenyoni). In addition, both sperm whales (Physeter macrocephalus) and killer whales were detected acoustically (Rone et al. 2009). Sighting data were sufficient to derive line-transect abundance estimates for fin and humpback whales. The Navy funded a second systematic survey of the Study Area that occurred from 23 June to 18 July 2013 (Rone et al. 2014). The main goal of the second Gulf of Alaska Line-Transect Survey (GOALS II) was to collect data to assess the abundance and spatial distribution of marine mammals from both visual sighting data and passive acoustics using a towed-hydrophone array and sonobuoys. Sighting and acoustic data were collected from four survey strata designed to sample the diverse habitat present in the Study Area, including a continental shelf or “inshore” stratum (22,749 square kilometers [km2]), slope stratum (36,776 km2), pelagic or “offshore” stratum (60,051 km2), and seamount stratum (45,377 km2). During the survey, there were 802 marine mammal sightings (1,998 individuals) of 13 confirmed species. Confirmed species were Baird’s (Berardius bairdii) and Cuvier’s (Ziphius cavirostris) beaked whales, blue (Balaenoptera musculus), sperm, fin, humpback, gray, killer and minke whales, Dall’s and harbor porpoise, and elephant (Mirounga angustirostris) and northern fur (Callorhinus ursinus) seals. There were an additional 162 sightings (261 individuals) of unidentified cetaceans and pinnipeds (Rone et al. 2014). Sighting data were sufficient to derive updated line-transect abundance estimates for fin and humpback whales, and new Study Area abundance estimates for blue, sperm, and killer whales, as well as Dall’s porpoise and northern fur seals (Rone et al. 2014). Acoustic data gathered during the GOALS II survey were also analyzed to develop the first acoustic-based line-transect survey estimates of abundance for Cuvier’s beaked whales within the Gulf of Alaska (U.S. Department of the Navy 2015). In order to obtain additional information on the occurrence and seasonality of cetaceans in the Study Area, in July 2011 the Navy deployed two High-frequency Acoustic Recording Packages (HARPs) on the shelf (200 meters [m]) and slope (900 m) regions in the north-central Gulf of Alaska (Baumann-Pickering et al. 2012b). During the first 7 months of passive acoustic monitoring, at least 10 species were detected (blue

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