The overall goal of this study was to include the 2018 survey data in the previous 1991–2014 modeling dataset in order to improve SMDs for the CCE study area. Specific objectives included: Generating multi-year average density surfaces for the Navy and others to use in their long-term (2–7 year) environmental planning efforts; and Providing updated abundance and “minimum population size (Nmin)” estimates as defined in the Guidelines for Assessing Marine Mammal Stocks (National Oceanic and Atmospheric Administration 2016).

Beaked whales are among the most poorly understood marine mammals. They are deep-diving odontocetes, spending most of their time submerged with infrequent, short surface intervals. Due to this behavior, they are difficult to study using visual observation methods alone . However, recent advancements in passive acoustic detection and survey techniques have shown to provide viable methods for stu dying beaked whales (Yack et al. 2013). In the Gulf of Alaska (GOA), there is little known abo ut beaked whale abundance and distribution.

Passive acoustic monitoring was conducted to detect the presence of marine mammal and anthropogenic sounds in the Navy’s Northwest Training Range Complex (NWTRC) from September 14, 2012 until June 30, 2013. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz at the shelf slope near Quinault Canyon. Data analysis methods consisted of detection of sounds by analyst scans of long-term spectral averages (LTSAs) and spectrograms, and by automated computer algorithms when possible. The data were divided into three frequency bands for analysis of marine mammal vocalizations and anthropogenic sounds.

Passive acoustic monitoring was conducted in the Navy’s Southern California Range Complex from December 2012 to January 2014 to detect marine mammal and anthropogenic sounds. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz at three locations: near Santa Barbara Island (880 m), west of San Clemente Island (1000 m), and southwest of San Clemente Island (1300 m). Six baleen whale species were recorded: blue whales, Bryde’s whales, fin whales, gray whales, humpback whales, and minke whales.

Passive acoustic monitoring was conducted in the Gulf of Alaska Temporary Maritime Activities Area (GATMAA) from June 2013 to May 2014 to detect marine mammal and anthropogenic sounds. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz at five locations: a shelf site offshore Kenai Peninsula (200 m depth, site CA), a continental slope site in deep water (850 m depth, site CB), a slope site offshore Kodiak Island (230 m depth, site KO), a deep offshore site at Pratt Seamount (1000 m depth, site PT), and a deep offshore site at Quinn Seamount (930 m depth, site QN).

The goal of our project “Southern California Beaked Whale Occurrence from Towed Array Surveys” is to support the US Navy environmental compliance requirements for monitoring marine mammals. This research effort is performed by the University of California San Diego (UCSD) Scripps Institution of Oceanography (SIO) in La Jolla, CA as part of a larger effort. Data collected by a shipboard towed array acoustic survey for marine mammals is being analyzed. These data will provide for spatial assessment of Southern California beaked whale occurrence from towed array surveys.

In September 2023, a third multi-week expedition was conducted off the coast of Baja California, Mexico to relocate the unknown species of beaked whales encountered in 2020 as well as look for the BW43 beaked whale. Daily non-systematic searches were carried out close to shore off Bahia San Quintín

Beaked whales (family Ziphiidae) consist of at least 21 different species in six genera with relatively little known about many of the species. Research on this family of odontocetes has increased in the last two decades as a result of a mass stranding event of beaked whales in the Bahamas in 2000 in association with a U.S. Navy training event. Results of this research have identified echolocation click characteristics for several species from different areas of the world based upon both tag data and passive acoustic monitoring data

Marine mammal surveys, initiated as part of the CalCOFI cruises in 2004, were continued during 2016-2017. Visual monitoring incorporated standard line-transect survey protocol which includes two experienced observers scanning for marine mammals during transits between CalCOFI stations.

Passive acoustic monitoring was conducted in the Navy’s Southern California Range Complex during May 2011 – March 2012 to detect the presence of marine mammal and anthropogenic sounds. Highfrequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz with nearly continuous temporal coverage at a site near Santa Barbara Island (site M) and at a site west of San Clemente Island (site H). Data analysis consisted of detection of sounds of interest by analyst scans of long-term spectral averages and spectrograms, and by automated computer algorithm detection when possible. Representative sounds are presented in this report, as well as details of the computer algorithms used to detect them.

Passive acoustic monitoring was conducted at two sites in the Navy’s Southern California Range Complex during April 2010 – April 2011. These data provide information on the presence of marine mammals and anthropogenic sound sources. High‐frequency acoustic recording packages documented sounds between 10 Hz and 100 kHz with nearly continuous temporal coverage at a site near Santa Barbara Island (site M) and a site south of San Clemente Island (site N). For this reporting period, 8,099 hours of acoustic recordings were obtained from site M and 7,779 hours of recordings from site N. Data analysis methods consisted of analyst scans of long‐term spectral averages and spectrograms. The data were divided into three frequency bands and each band was analyzed for the sounds of marine mammal species or anthropogenic sources. Representative sounds are presented.

This report summarizes the underwater sounds detected during a series of deployments of a High Frequency Acoustic Recording Package (HARP) in the southern California (SOCAL) offshore region. The HARP records broadband (10 Hz – 100 kHz) acoustic data, including both marine animal and anthropogenic sound. This report summarizes initial analysis to detect the presence of marine mammals by species as well as the occurrence of naval sonar and other anthropogenic sound events.

This report summarizes the underwater sounds detected during a series of deployments of a High Frequency Acoustic Recording Package (HARP) in the southern California (SOCAL) offshore region. The HARP records broadband (10 Hz – 100 kHz) acoustic data, including both marine animal and anthropogenic sound. This report summarizes initial analysis to detect the presence of marine mammals by species as well as the occurrence of naval sonar and other anthropogenic sound events.

Passive acoustic monitoring was conducted in the Navy’s Southern California Range Complex during March 2012 through December 2012 to detect the presence of marine mammal and anthropogenic sounds. High-frequency Acoustic Recording Packages (HARPs) recorded sounds between 10 Hz and 100 kHz with continuous temporal coverage at a site near Santa Barbara Island (site M), at a site west of San Clemente Island (site H), and a site southwest of San Clemente Island (site N).

Passive acoustic monitoring using High-frequency Acoustic Recording Packages (HARPs) was conducted at two sites in the Navy’s Northwest Training Range Complex; one on the continental shelf near Cape Elizabeth (CE) and the other at the shelf slope near Quinault Canyon (QC). The inshore shelf site was monitored from December 2011 until January 2012, and the offshore shelf slope site was monitored from December 2011 until July 2012. In this report, information on the presence of marine mammals and anthropogenic sounds collected at these sites is presented.

The Gulf of Alaska is an important habitat for a diverse array of marine mammals, many of which were severely depleted by historical whaling. To study current cetacean distributions in this region, passive acoustic monitoring was used to detect species-specific call types between 2011 and 2015 at five locations spanning the continental shelf, slope, and offshore seamounts. Spatial and temporal detection patterns were examined for nine species to compare differences in behavior and habitat use.

During this survey, the visual team surveyed 4,504 kilometers (km) of ‘full-effort,’ which included 349 km of ‘transit-effort.’ There was an additional 375 km of ‘fog-effort’ (transect and transit). Based on total effort, there were 802 sightings (1,998 individuals) of 13 confirmed marine mammal species, with an additional 162 sightings (228 individuals) of unidentified cetaceans and pinnipeds (including those recorded on transit and during off-effort mode).

The Southern California (SOCAL) portion of the Hawaii-Southern California Training and Testing (HSTT) area (SOCAL TR) is one of the United States Navy’s most active training areas, particularly for mid-frequency active sonar (MFAS). Much of SOCAL lies within the Southern California Bight, a productive oceanographic region that hosts a wide variety of marine species. As part of an ongoing study of the distribution and demographics of several marine mammal species within SOCAL, we conducted 32 days of survey effort from 6 January 2022 to 26 November 2022, specifically focusing on the Southern California Anti-submarine Warfare Range (SOAR).

Here we present analyses of the DASBR deployments from the CCES 2018 project. We provide information on the times and locations of drift deployments and retrievals. Each drift is also illustrated on maps of the study area. We present analyses of cetacean echolocation detections 2 from DASBR recordings including those from beaked whales, sperm whales, and NBHF species. As in the previous 2016 study, beaked whale detections were dominated by Cuvier’s beaked whale. All the beaked whale species detected in 2016 were also detected in this 2018 study, plus the addition of a signal, designated BWC that had been previously detected in the central and western Pacific, but not previously in the eastern Pacific. Sperm whales and NBHF species were detected throughout the study area.

This report summarizes the results from SOCAL-11, the second year of the research project Southern California Behavioral Response Study (SOCAL-BRS) conducted in the Southern California Bight. The study’s overall objective is to provide a better understanding of marine mammal behavior and a direct scientific basis to estimate the risk and minimize adverse effects of human sounds, particularly military sonar, on marine mammals. During a scouting phase and two operational legs of SOCAL-11, researchers observed, photographed, and/or tracked thousands of individuals of 18 marine mammal species. Thirty-eight tags were secured on 35 individual animals of four different marine mammal species, including many on focal species including blue whales, Risso’s dolphins, and Cuvier’s beaked whales.

Passive acoustic monitoring was conducted in the Navy’s Northwest Training Range Complex from July 2013 to April 2014 to detect marine mammal and anthropogenic sounds. Three baleen whale species were detected: blue whales, fin whales, and humpback whales. Minke whale boings, which were first recorded in the NWTRC in November 2012, were not detected during this monitoring period. Likewise, North Pacific right whale up-calls were detected for the first time in the NWTRC in June 2013, but there were no definitive detections of this species during this recording period. Frequencymodulated echolocation pulses from three beaked whale species were detected at the offshore site. Three anthropogenic sounds were detected in the recordings: mid-frequency active and low-frequency active sonars, and explosions.

A visual and acoustic line-transect survey of marine mammals was conducted in the central Gulf of Alaska (GoA) during the summer of 2013. The survey area was divided into four sub-strata to reflect four distinct habitats; ‘inshore’, ‘slope’, ‘offshore’ and ‘seamount’. Passive acoustic monitoring was conducted using a towed-hydrophone array system. One of the main objectives of the acoustic survey was to obtain an acoustic-based density estimate for beaked whales. Three species of beaked whales were identified; Cuvier’s (Ziphius cavirostris), Baird’s (Berardius bairdii) and Steijneger’s (Mesoplodon stejnegeri).