The Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS) 2017 was conducted in waters within the United States (U.S.) Exclusive Economic Zone (EEZ) around the Hawaiian Archipelago (henceforth “Hawaiian EEZ” for brevity) from 6 July through 1 December 2017 (Yano et al. 2018). The primary objective of this line-transect survey was to collect cetacean sighting data to support the derivation of cetacean density estimates using both design-based analyses and habitat modeling techniques.

The Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS) is a recurring ship-based, line-transect survey designed to estimate cetacean abundance in the entirety of the Hawaiian EEZ.

To monitor for the presence of marine mammals, High-frequency Acoustic Recording Packages (HARPs) were deployed at two sites within the Navy’s Virginia Capes Range Complex. There were three deployments at one site, located offshore from Cape Hatteras (HAT), between October 2012 and December 2014. There was one deployment at the other site, located offshore from Norfolk Canyon (NFC), between June 2014 and April 2015. Both sites were located approximately 75 nmi offshore in about 1000 m of water.

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.

This document contains amplifying technical data and information for the United States Department of the Navy’s Southern California Range Complex Comprehensive Monitoring Report.

Cetacean distribution and abundance are reported from the first systematic line-transect visual survey in the waters of Guam and the Commonwealth of the Northern Mariana Islands (CNMI). The survey was conducted during January–April 2007 following standard line-transect protocols. Trackline coverage (11,033 km) was dominated by high sea states (88.2%); however, 13 cetacean species were recorded.

Cetacean distribution and abundance are reported from the first systematic line-transect visual survey in the waters of Guam and the Commonwealth of the Northern Mariana Islands (CNMI). The survey was conducted during January–April 2007 following standard line-transect protocols.

In order to support the U.S. Navy in meeting regulatory requirements for monitoring established under the Final Rules and to provide a mechanism to assist with coordination of program objectives under the ICMP, this survey was conducted to confirm the Marine Mammal Monitoring on Navy Ranges (M3R) acoustic detections and marine mammal satellite tagging was prior to a training event, the Submarine Commander’s Course exercise, which would be conducted in the same area during February 2012.This report presents the methods and preliminary results of a vessel-based visual and acoustic survey effort that was conducted in conjunction with a tagging and species-validation project

The overall objective of the ICMP is to assimilate relevant data collected across U.S. Navy range complexes in order to answer questions pertaining to the impact of MFAS and explosives on marine mammals and sea turtles.

This report presents a geographic information system (GIS)-based overview of the sighting records obtained during marine species monitoring effort (a total of 12 U.S. Pacific Fleet-funded surveys) to date in the MIRC. Also included are incidental marine mammal and sea turtle sightings made since 1965 on non-dedicated surveys in the region.

The first phase to integrate the historical sum of these U.S. Navy-sponsored visual survey efforts for marine species monitoring in the HRC was prepared by Uyeyama (2011). This report represents the second phase of that effort and presents an overview of monitoring survey effort to date in the HRC. Available data from visual surveys performed by both contractor-led efforts and U.S. Navy in-house surveys was compiled and processed in order to: 1. Create a geographic information system (GIS)-based summation of all survey tracks that can be easily visualized. 2. Construct a geo-referenced database of sightings that can be queried by species, observer platform, Beaufort Sea State (BSS), season, or other sighting/survey variables. 3. Conduct an enhanced analysis of sighting success with respect to survey platform, field protocol, and environmental conditions. 4. Inform and adjust data collection procedures on future surveys as needed to reflect lessons learned from sighting data compilation efforts presented here. 5. Provide information to enhance informed management of marine protected species in the HRC and support the adaptive management process that is part of the ICM

A Time Difference of Arrival (TDOA) method was used to acoustically localize vocalizing Bryde's whales (Balaenoptera brydei) on the Navy's Pacific Missile Range Facility (PMRF) in Hawaii. Over 130 days of data were recorded from 2011- 2015, resulting in over 12 Bryde's tracks. The tracks were analyzed for cue rates, swim patterns, bearing, directivity, speed, and dive depths. In six of the encounters the Bryde's appear to be traveling in fairly constant headings (typically south-southwest or westerly) crossing the range area over distances ranging from 12 to 27 km over time periods of 1.5 to 6 h with estimated swim speeds up to 12 km/h. Vocalizing whales produced acoustic cues every 3-7 minutes while transiting. Although the occurrence of transiting Bryde's whales is relatively low, the tracks can provide valuable information about the habitat use of this offshore region, particularly because both visual surveys and animal tagging is difficult in this area.

A unique acoustic call type was identified and attributed to Bryde’s whales in the central North Pacific in 2015, but little is known about the distribution, calling behavior, or swimming behavior of Bryde’s whales in the region. Acoustic detections attributed to Bryde’s whales were used to localize and track individual whales on the U.S. Pacific Missile Range Facility (PMRF) in Kaua‘i, Hawai‘i. This study included 150 acoustically derived tracks from recordings spanning the years 2011–2022 with recording effort in nearly every month. Bryde’s whale movement was examined relative to calendar year, day of year, hour of day, wind speed, and acoustic calling rate. Hidden Markov models were used to identify two kinematic states (slower, less directional movement and faster, more directional movement). The findings indicate that Bryde’s whales were more likely to travel in a faster and more directional state during the daytime than at night and between May and August when compared to other times of year. The along-track acoustic cue rate was examined for 118 tracks, and the findings indicate a possible lengthening of the median inter-call interval over the duration of the study period. These results are an important first step in understanding more about behavior in Bryde’s whales, a relatively under-studied species.

An expedition was conducted with the goal of visually locating, acoustically recording, and obtaining biopsy samples of the Mesoplodon beaked whales that were encountered in 2020 and produce BWB pulses, as well as locating the beaked whales that produce the BW43 echolocation pulse in order to conclusively determine what species produce each of the pulse types.

Beaked whales (Family Ziphiidae; Order Cetacea) are the least well-described group of marine mammals because they conduct very long deep dives, spend little time on the surface where they display cryptic behavior, and are difficult to identify due to the similarity between species. Beaked whales are also known to be susceptible to high-energy sound sources in the ocean (e.g. seismic research, sonars used by military activities).

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 using High-frequency Acoustic Recording Packages (HARPs) deployed in waters offshore of Virginia, North Carolina, and Florida with support from the US Navy during 2016 - 2017. The HARPs recorded underwater sounds between 10 Hz and 100 kHz. Data analysis consisted of analyst scans of long-term spectral averages (LTSAs) and spectrograms, and automated computer algorithm detection when possible. Three frequency bands were analyzed for marine mammal vocalizations and anthropogenic sounds: (1) Lowfrequency, between 10-1000 Hz, (2) Mid-frequency, between 1,000-5,000 Hz, and (3) Highfrequency, between 1-100 kHz.

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.

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.

The PIFSC CRP has conducted research on cetaceans in the Mariana Archipelago since 2010. A cooperative effort with funding from U.S. Navy Pacific Fleet and PIFSC has included summer and winter small-boat surveys off the southernmost islands (Saipan, Tinian, Aguijan, Rota, and Guam), development of photo-ID catalogs, analysis of collected tissue samples and satellite telemetry tag data, and shipboard visual and PAM surveys in portions of the EEZ in 2010 and 2015. PIFSC has maintained long-term PAM on moored recorders off Saipan and Tinian (since 2010) and off Pagan (since 2015) as part of the Pacific Islands Passive Acoustic Network (PIPAN). The goal of these efforts is to collect the data necessary to conduct population assessments for cetaceans within the Mariana Archipelago, including the determination of their occurrence, population structure and abundance, movements, distribution, and habitat use.

The Pacific Islands Fisheries Science Center’s (PIFSC) Cetacean Research Program (CRP) has been conducting visual surveys and long-term acoustic monitoring for cetaceans in the waters surrounding Guam and the Commonwealth of the Northern Mariana Islands (CNMI) as part of an ongoing effort to develop a record of cetacean occurrence in the region. Visual surveys have been conducted aboard small boats (7.6–12.2 m) since 2010 off the southernmost islands of the Mariana Archipelago (Guam, Rota, Saipan, Tinian, and Aguijan). These surveys include the collection of photographs for individual identification, tissue samples for genetic analysis of population structure, and the deployment of satellite tags for assessment of individual movements throughout the broader region.

The Pacific Islands Fisheries Science Center’s (PIFSC) Cetacean Research Program (CRP) has been conducting visual surveys and long-term acoustic monitoring for cetaceans in the waters surrounding Guam and the Commonwealth of the Northern Mariana Islands (CNMI) as part of an ongoing effort to develop a record of cetacean occurrence in the region. Visual surveys have been conducted aboard small boats (7.6-12.2 m) since 2010 off the southernmost islands of the Mariana Archipelago (Guam, Rota, Saipan, Tinian, and Aguijan). These surveys include the collection of photographs for individual identification, tissue samples for genetic analysis of population structure, and the deployment of satellite tags for assessment of individual movements throughout the broader region.

Bryde’s whales (Balaenoptera brydei/edeni) have been considered an anomalous occurrence in the Southern California Bight (SCB). Thus, they typically have been excluded from species lists associated with SCB management documents. In the last 40 years only two visual sightings of Bryde’s whales were documented in California waters, the last one in 1991 (Carretta et al. 2007). This is despite extensive systematic vessel and aerial surveys and presumed recent recordings of Bryde’s whale vocalizations in the SCB. Bryde’s whales are notoriously difficult to differentiate in the field and from fin (B. physalus) and sei whales (B. borealis), given the subtle differences in physical characteristics. Between August 2006 and September 2010, we photo-documented five sightings of five single Bryde’s whales in the SCB. Two of the five sightings occurred in October 2008 and September 2010 during 33,880 km of aerial surveys. The remaining three sightings occurred during small-vessel surveys that included offshore waters: two in June 2006 and one in September 2010. These sightings combined with other reports of presumed vocalizations suggest that Bryde’s whale numbers may be increasing in the SCB. This may be related to global warming, large-scale oceanographic events (e.g., El Niño and La Niña) and resulting changes in prey availability. However, no clear association pattern was evident between ENSO events and our sightings. The recent sightings reported herein indicate that the Bryde’s whale should be considered as a species present in the SCB and photodocumentation is critical to ascertain species.

Bryde's whales (Balaenoptera brydeij edem) have been considered an anomalous occurrence in the Southern California Bight (SCB). Thus, they typically have been excluded from species lists associated with SCB management documents. In the last 40 years only two visual sightings of Bryde's whales were documented in California waters, the last one in 1991 (Carretta et al. 2008). This is despite extensive systematic vessel and aerial surveys and presumed recent recordings of Bryde's whale vocalizations in the SCB. Bryde's whales are notoriously difficult to differentiate in the field, both from each other and also from fin (B. physa/us) and sei whales (B. borealis), given the subtle differences in physical characteristics. Between August 2006 and September 2010, we photo-documented five sightings of five single Bryde's whales in the SCB. Two of the five sightings occurred in October 2008 and September 2010 during 33,880 km of aerial surveys. The remaining three sightings occurred during small-vessel surveys that included offshore waters: two in June 2006 and one in September 2010. These sightings combined with other reports of presumed vocalizations suggest that Bryde's whale numbers may be increasing in the SCB. This may be related to global warming, large-scale oceanographic events (e.g., El Nino and La Nina) and resulting changes in prey availability. Recent sightings reported herein indicate that the Bryde's whale should be considered as a species present in the SCB and photo-documentation is critical to ascertain species.

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).

Bryde’s whales (Balaenoptera edeni) are commonly found in tropical and subtropical regions of the Pacific Ocean, but few studies have explored the presence of Bryde’s whales at the boundary of their distribution range. Such studies are increasingly relevant as climate impact models predict the range expansion of warm water species towards the poles in response to ocean warming. Like other baleen whales, Bryde’s whales produce distinct low frequency (o60 Hz) calls, which can be used for long-term acoustic monitoring of whale presence in an area. Autonomous passive acoustic recorders deployed at f ive sites in the Southern California Bight (SCB) were used to investigate the presence of Bryde’s whales in temperate waters from 2000 to 2010. Calling Bryde’s whales were observed in the SCB from summer to early winter, indicating a seasonal poleward range expansion. There was a significant increase in the presence of calling Bryde’s whales in the SCB between 2000 and 2010, but no significant correlation was found between Bryde’s whale presence and local sea surface temperature. Bryde’s whale occurrence is likely driven by prey availability within the California Current ecosystem, which is affected by seasonal and inter-annual changes in climate and oceanographic conditions. Continued monitoring of Bryde’s whales and their prey in the eastern North Pacific is needed to provide a longer time series and determine the full effect of climate variability and ocean warming on the distribution of this species.

Bryde’s whales (Balaenoptera edeni) are commonly found in tropical and subtropical regions of the Pacific Ocean, but few studies have explored the presence of Bryde’s whales at the boundary of their distribution range. Such studies are increasingly relevant as climate impact models predict the range expansion of warm water species towards the poles in response to ocean warming. Like other baleen whales, Bryde’s whales produce distinct low frequency (o60 Hz) calls, which can be used for long-term acoustic monitoring of whale presence in an area. Autonomous passive acoustic recorders deployed at f ive sites in the Southern California Bight (SCB) were used to investigate the presence of Bryde’s whales in temperate waters from 2000 to 2010. Calling Bryde’s whales were observed in the SCB from summer to early winter, indicating a seasonal poleward range expansion. There was a significant increase in the presence of calling Bryde’s whales in the SCB between 2000 and 2010, but no significant correlation was found between Bryde’s whale presence and local sea surface temperature. Bryde’s whale occurrence is likely driven by prey availability within the California Current ecosystem, which is affected by seasonal and inter-annual changes in climate and oceanographic conditions. Continued monitoring of Bryde’s whales and their prey in the eastern North Pacific is needed to provide a longer time series and determine the full effect of climate variability and ocean warming on the distribution of this species.

Climate impact models predict the range expansion of warm water species towards the poles in response to ocean warming. Bryde's whales (Ba/aenoptera edem) are commonly found in tropical and subtropical regions of the Pacific Ocean, but few studies have explored the presence of Bryde's whale at the boundaries of their distribution ranges. Like other baleen whales, Bryde's whales produce distinct low frequency (

Low frequency pulsed signals between 12 and 64 Hz have been detected, localized and tracked automatically using acoustic data recorded at the Pacific Missile Range Facility, Kauai, Hawaii (PMRF)

This report documents Naval Information Warfare Center Pacific (NIWC Pacific) marine mammal monitoring efforts in fiscal year (FY) 2022 for Commander, Pacific Fleet (COMPACFLT) at the Pacific Missile Range Facility (PMRF), Kaua'i, Hawai

This report documents SSC Pacific marine mammal monitoring efforts in FY16 for COMPACFLT at the Pacific Missile Range Facility (PMRF), including during U.S. Navy mid-frequency active sonar (MFAS) training. Data products (i.e., recorded hydrophone data, standard PMRF range products, and range craft deployed calibrated hydrophone data) were obtained and analyzed using custom detection, classification and localization tools described herein.

This report documents Space and Naval Warfare Systems Center Pacific (SSC Pacific) marine mammal monitoring efforts in FY15 for COMPACFLT at the Pacific Missile Range Facility (PMRF), Kauai, Hawaii, including during U.S. Navy mid-frequency active sonar (MFAS) training. Data products (both recorded hydrophone data and standard PMRF range products) were obtained and analyzed. Collaborative efforts with R. Baird and B. Southall were also performed involving estimating received levels for tagged animals that were exposed to MFAS during training activities.

This report documents the Naval Information Warfare Center (NIWC) Pacific Whale Acoustic Reconnaissance Project (WARP) Laboratory’s marine mammal monitoring efforts in fiscal year (FY) 2023 for Commander, Pacific Fleet (COMPACFLT) at the Pacific Missile Range Facility (PMRF), Kaua‘i, Hawai‘i.

This report documents the Naval Information Warfare Center (NIWC) Pacific Whale Acoustic Reconnaissance Project (WARP) Laboratory’s marine mammal monitoring efforts in fiscal year (FY) 2024 for Commander, Pacific Fleet (COMPACFLT) at the Pacific Missile Range Facility (PMRF), Kaua‘i, Hawai‘i.

Bryde’s whales (Balaenoptera brydei/edeni) have been considered an anomalous occurrence in the Southern California Bight (SCB). Thus, they typically have been excluded from species lists associated with SCB management documents. In the last 40 years only two visual sightings of Bryde’s whales were documented in California waters, the last one in 1991 (Carretta et al. 2008). This is despite extensive systematic vessel and aerial surveys and presumed recent recordings of Bryde’s whale vocalizations in the SCB. Bryde’s whales are notoriously difficult to differentiate in the field, both from each other and also from fin (B. physalus) and sei whales (B. borealis), given the subtle differences in physical characteristics. Between August 2006 and September 2010, we photo-documented five sightings of five single Bryde’s whales in the SCB. Two of the five sightings occurred in October 2008 and September 2010 during 33,880 km of aerial surveys. The remaining three sightings occurred during small-vessel surveys that included offshore waters: two in June 2006 and one in September 2010. These sightings combined with other reports of presumed vocalizations suggest that Bryde’s whale numbers may be increasing in the SCB. This may be related to global warming, largescale oceanographic events (e.g., El Niño and La Niña) and resulting changes in prey availability. Recent sightings reported herein indicate that the Bryde’s whale should be considered as a species present in the SCB and photo-documentation is critical to ascertain species.

Aerial surveys of marine mammal and turtle species were conducted during the period Aug. 13- 17, 2007 following completion of the “Valiant Shield” naval exercises in waters off the Northern Mariana Islands. Surveys encompassed approximately 2,352 km of linear effort, with transect grids distributed randomly throughout a 163,300 km2 target area.

With funding from the Living Marine Resources (LMR) Program, the Marine Mammal Monitoring on Navy Ranges (M3R) passive acoustic monitoring system has been installed at the Pacific Missile Range Facility (PMRF). The overall goal of the program is to provide tools and methodologies for long-term monitoring of marine mammal populations. The program is laying the groundwork needed to adapt combined passive acoustic, tagging, and visual monitoring methods for animals and conditions at PMRF. For sonar-sensitive Blainville’s beaked whales (Mesoplodon densirostris; Md), the short- and long-term distribution, density, and habitat can be measured provided basic behavioral data such as group size and dive rates at PMRF are known.

This report covers two separate activities carried out by the Cetacean Research Program at the Pacific Islands Fisheries Science Center from February to June 2009. A cetacean assessment survey of the main Hawaiian Islands was conducted by NMFS in February 2009. The survey was designed to conform to the 2002 NMFS HICEAS survey (Hawaiian Islands Cetacean Ecosystem Assessment Survey) so that abundance and distribution estimates would be comparable.

This report summarizes three aerial surveys conducted between 31 August 2011 and 31 July 2012 on the Navy’s Southern California Range Complex (SOCAL), and includes results from the first year of deploying sonobuoys from the aircraft to simultaneously monitor both acoustic and visually observed behaviors.

In support of the U.S. Navy’s (Navy) Marine Mammal Monitoring Plan (M3P) in the Southern California Range Complex (SOCAL) (DoN 2009), aerial surveys were conducted by Marine Mammal Research Consultants (MMRC) and Smultea Environmental Sciences (SES) to monitor marine mammals and sea turtles (MM/ST) during June and July 2009 in the SOCAL area.

Aerial surveys were conducted in conjunction with two US Navy (Navy) Major Training Events (MTE) involving mid-frequency active sonar (MFAS) and explosives in October (Oct) and mid-November (Nov) 2008 in the Southern California Range Complex (SOCAL) off San Diego, California. The purpose of this survey was to monitor potential effects or lack of observable effects of MFAS and explosives on mammals and sea turtles (MM/ST) during a MTE from 17-21 Oct and beginning one day after a MTE from 15-18 Nov.

The relative occurrence of the 16 most common cetacean species in the Southern California Bight (SCB) was compared from the 1950s through 2012 by examining at-sea sighting and stranding data. While systematic survey and population abundance/density data have been available since the 1970s, prior data were collected opportunistically. Comparisons were made through a literature review and using recent results from 15 aerial surveys conducted in the SCB from 2008 through 2012. We attempted to address inconsistency in type of effort across studies by ranking the relative sighting frequency of the most common species based on the most representative study for each period. This comparison revealed changes in the relative occurrence of some species across the approximately 60-y reviewed period. Since the 1950s, common dolphins have remained the most common “species” of cetacean in the SCB. Risso’s dolphin and fin, blue, humpback, and Bryde’s whales appear to have increased in relative occurrence. The relative occurrence of the common bottlenose and northern right whale dolphins; Dall’s porpoise; and gray, killer, minke, Cuvier’s beaked, and sperm whales do not appear to have changed notably since the 1950s. There is possible indication of recent decreased relative occurrence of the Pacific white-sided dolphin. The short-finned pilot whale has decreased since the 1950s and has not been recorded in the SCB since the 1990s, concurrent with the observed relative increase in Risso’s dolphins. Overall, recent aerial surveys indicate that the 16 most commonly seen species in the SCB, in descending order of frequency, were common dolphins (two species), Risso’s dolphin, fin whale, common bottlenose dolphin, gray whale, blue whale, Pacific white-sided dolphin, humpback whale, northern right whale dolphin, common minke whale, Dall’s porpoise, killer whale, Bryde’s whale, Cuvier’s beaked whale (the latter three tied in ranking), and sperm whale. Given that the reviewed historical data from the 1950s and 1960s are virtually the only sources of information available to examine trends over the last 50 to 60 y in this area, we believe this comparative ranking approach provides useful information not available from other sources.

The SEFSC and Scripps Institution of Oceanography have been collaboratively deploying long-term passive acoustic monitoring stations at five Gulf of Mexico (GOM) sites since 2010 to monitor the impacts of the Deepwater Horizon oil spill and subsequent restoration activities on cetaceans (Figure 1). High-frequency Acoustic Recording Packages (HARPs), deployed at the five sites, including the De Soto Canyon (DC) HARP in the primary GOM Bryde’s whale habitat, have been continuously recording ambient noise and other acoustic events in the 10 Hz to 100 kHz frequency range, and these 8-year nearcontinuous recordings are available for analysis to better understand distribution and density trends of cetaceans, potentially including GOM Bryde’s whales. Data from the DC HARP site have only been evaluated for downsweep call sequences in the first year of data (Širović et al., 2014), and have not been evaluated for probable long-moan calls or constant tonal calls (Rice et al., 2014), which have also recently been recorded by SEFSC in the presence of GOM Bryde’s whales. Over late 2018 through 2020, this project focuses on developing automated GOM Bryde’s whale call detectors and analyzing the full 8 years of data from the DC HARP in the core habitat (Table 1), to establish complete occurrence timeseries for understanding seasonal and interannual trends and for future habitat modeling and density estimation. The 2018-19 goals were to develop the detectors and run and validate them on the first 38 months of data collected between October 2010 and July 14. They 2020 goals are to complete the validation on the detector results on the remaining data and begin a new data collection project that builds upon these results to better understand temporal variability in occurrence.

The SEFSC and Scripps Institution of Oceanography have been collaboratively deploying long-term passive acoustic monitoring stations at five Gulf of Mexico (GOM) sites since 2010 to monitor the impacts of the Deepwater Horizon oil spill and subsequent restoration activities on cetaceans (Figure 1). High-frequency Acoustic Recording Packages (HARPs), deployed at the five sites, including the De Soto Canyon (DC) HARP in the GOM Bryde’s whale core habitat, have been continuously monitoring ambient noise and other acoustic events in the 10 Hz to 100 kHz frequency range, and 8 years of nearcontinuous recordings (2010-2018) are available for analysis to better understand distribution and density trends of cetaceans, potentially including GOM Bryde’s whales. Data from the DC HARP site had previously only been evaluated for downsweep call sequences in the first year of data (Širović et al. 2014), and had not been evaluated for probable long-moan calls or constant tonal calls (Rice et al. 2014), which have also recently been recorded by SEFSC in the presence of GOM Bryde’s whales. Over late 2018 through 2020, this project focused on developing automated GOM Bryde’s whale call detectors and analyzing the full 8 years of data from the DC HARP in the core habitat (Table 1), to establish complete occurrence time-series for understanding seasonal and interannual trends and for future habitat modeling and density estimation. The 2018-19 goals were to develop the detectors and run and validate them on the first 38 months of data collected between October 2010 and July 2014. The 2020 goals were to complete the validation of the detector results on the remaining data and to begin a new data collection project that builds upon these results to better understand temporal variability in occurrence.

The objective of Mariana Islands Sea Turtle and Cetacean Survey (MISTCS) was to conduct the first systematic line-transect visual survey of the waters around Guam and the Northern Mariana Islands and generate density estimates for those species which had adequate data.

In spring/summer of 2018 and 2021, the Pacific Islands Fisheries Science Center Cetacean Research Program deployed drifting acoustic recorders in the U.S. Exclusive Economic Zones surrounding the Mariana Archipelago. Manual assessments revealed a low-frequency (median 473-554 Hz), short-duration (median 0.596 s), stereotypic tonal nocturnal call throughout the Mariana Archipelago. Based on time of year, spatiotemporal patterns, clear division among calls (i.e., no chorusing), comparisons with known vocalizations of whales, turtles, and fish, and presence of Bryde's whale calls, and because the call has not been detected elsewhere, we hypothesize this 500-Hz pulsed call is produced by Bryde's whales (Balaenoptera brydei).

The purpose of this report is to compile previously unpublished sightings of marine mammals and sea turtles made in the Mariana Islands Range Complex. The original primary goal of this report was to compile such sightings incidentally made during Navy-funded field efforts or other Navy training. However during the course of compiling these data, additional incidental sightings made by other sources were encountered.

This project provides support for comprehensive stranding investigations in order to obtain increased baseline information about the health of marine mammals. Such support is essential when considering the Pacific Islands region (PIR) where unique geographical challenges exist. The PIR is comprised of isolated islands, spanning over 4 million square miles across the North, South and Western Pacific basins and includes the Hawai‘i Range Complex and the Mariana Islands Range Complex. All cetacean stranding response and investigative efforts for the PIR are centralized at a dedicated stranding facility located at Marine Corps Base Hawai‘i (MCBH). This specialized facility houses the University of Hawai‘i (UH) Health and Stranding Lab, which plays a critical role as the only organization in the region to conduct cause of death investigations when dolphins and whales strand. This requires mounting an immediate response to each newly reported stranding event that occurs and conducting extensive necropsy examinations, including histopathology, disease surveillance, and tissue sampling in support of numerous research efforts aimed at better understanding Hawaiian cetaceans. In addition to this project facilitating advanced diagnostics in-house at the Health and Stranding Lab, we also report on progress towards a project option to measure fecal stress and reproductive hormones in Pacific Island cetaceans. An additional project option includes characterizing marine debris ingestion by abundance and mass in previously stranded short-finned pilot whales.

The primary goals of Winter HICEAS 2020 were to collect data required to estimate the abundance and distribution, examine the population structure, and understand the habitat of cetaceans around the main Hawaiian Islands during the winter months (January–March). There were 5 major research components to the project: visual observations for cetaceans following a line-transect survey design; passive acoustic monitoring for cetaceans using towed hydrophone arrays, sonobuoys, and autonomous drifting acoustic recorders; collection of photographs and tissue samples and deployment of satellite tags for select cetacean groups; visual observations for seabirds following a strip-transect survey design; and ecosystem measurements for assessment of cetacean and seabird habitat.