In August 2017, a marine mammal monitoring project was carried out combining boat-based field efforts and passive acoustic monitoring on and around the Pacific Missile Range Facility (PMRF). Commander, Pacific Fleet (PACFLT) funded five days of small-boat effort and the National Marine Fisheries Service funded an additional six days of effort. Information obtained was compared to previous sightings during small-boat effort by Cascadia Research Collective (CRC) off Kauai and Niihau, during 1,119 hr of effort (19,194 km) over nine different years from 2003 through 2016 (see Baird 2016)

As part of the long-term United States (U.S.) Navy-funded Marine Species Monitoring Program, from 1-14 August 2021, a combination of boat-based field effort and passive acoustic monitoring was carried out on and around the underwater hydrophone ranges of the Pacific Missile Range Facility (PMRF).

Here we combine results of field efforts funded through the U.S. Navy’s Living Marine Resources Program (through a three-year grant from the Naval Postgraduate School) as well as additional field time in the study area in 2011 and 2012 funded through the Pacific Islands Fisheries Science Center and Commander, Pacific Fleet. We also utilize results from research efforts in the eastern main Hawaiian Islands, off Lāna‘i, Maui, and Hawai‘i Island, to help interpret results from photo-identification and satellite tagging.

A number of species of resident and non-resident odontocetes use the waters of the Kaulakahi Channel between Kaua‘i and Ni‘ihau, overlapping with the Pacific Missile Range Facility (PMRF). Submarine Command Courses (SCCs) held at PMRF provide an opportunity to assess exposure and measure odontocete reactions to mid-frequency active sonar (MFAS) being used in realistic training scenarios. The primary goal of this assessment was to estimate MFAS received levels (RLs) for satellite tagged odontocetes and determine whether any large-scale movements occurred in response to hull-mounted surface ship MFAS exposure. Two prior reports have used odontocete satellite tag data and information on MFAS use to estimate RLs for animals tagged in 2011 through 2015.

As part of an assessment of habitat use and movements of odontocetes being undertaken in the western half of the main Hawaiian Islands (see Baird et al. 2011, 2012), field operations funded by Commander, U.S. Navy Pacific Fleet were undertaken off of Kaua‘i in January 2012. There were two primary goals of these operations: 1) providing species verification for acoustic detections by the Marine Mammal Monitoring on Navy Ranges (M3R) project on the Pacific Missile Range Facility (PMRF) hydrophone range (see Moretti et al. 2012); and 2) deploying satellite tags prior to a Submarine Commanders Course (SCC) training event to be undertaken off Kaua‘i in February 2012.

Movements and Spatial Use of Satellite‐tagged Odontocetes in the Western Main Hawaiian Islands: Results of Fieldwork Undertaken off O‘ahu in October 2010 and Kaua‘i in February 2011

As part of a long-term U.S. Navy-funded marine mammal monitoring program, in August 2018 a combination of vessel-based field effort and passive acoustic monitoring was carried out on and around the Pacific Missile Range Facility (PMRF) Kaua‘i prior to a Submarine Commander Course scheduled for mid-August 2018. The purpose of the monitoring effort was to assess the spatial movement patterns and habitat use of cetaceans that are exposed to mid-frequency active sonar and how those patterns influence exposure and potentially responses.

As part of a long-term U.S. Navy-funded marine mammal monitoring program, in February 2020 a combination of vesselbased field effort and passive acoustic monitoring was carried out on and around the Pacific Missile Range Facility (PMRF) off Kaua‘i prior to a Submarine Command Course scheduled for mid-February 2020. The purpose of the monitoring effort was to assess the spatial movement patterns and habitat use of cetaceans that are exposed to midfrequency active sonar and how those patterns influence exposure and potentially responses. Results from this effort were compared with previous Cascadia Research Collective (CRC) survey effort and photo-identification and tag data from Kaua‘i, based on surveys in 11 different years since 2003.

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.

The first cetacean circovirus, beaked whale circovirus (BWCV), was recently reported in a Longman’s beaked whale (Indopacetus pacificus) stranded in Hawai‘i and represents an emergent disease with unknown population impacts. In other species, circovirus infection may cause mortality or opportunistic co-infection by other pathogens. We report on a targeted surveillance of stranded cetaceans in the Pacific basin, including archived beaked whale species, strandings where pathological findings suggested disease presence, mass stranded animals, and additional individuals to represent a broad range of Hawaiian cetacean species. Archived tissues primarily from the brain, kidney, liver, lung, spleen, and lymph nodes of individuals stranded between 2000 and 2020 (n=30) were tested by PCR for the presence of BWCV.

A shore-based platform, incorporating two high-powered 25 × 150-millimeter binoculars ("Big Eyes"), was evaluated as an alternative approach for surveying marine areas for protected species (marine mammals and sea turtles). During a pilot study at a test site on Oahu (278-meter [m] elevation), humpback whale (Megaptera novaeangliae) blows were visible through Big Eyes at 37 kilometers (km) away in Beaufort Sea State (BSS) 2. This suggests the approach could be effective at detecting baleen and sperm whales from long distances, priority species under the United States Department of the Navy's Marine Species Monitoring Program.

A shore-based platform, incorporating high-powered 25×150mm binoculars ("bigeyes"), was evaluated as an alternative approach for surveying marine areas for protected species (marine mammals and sea turtles). During a pilot study at a test site on Oahu (273m elevation), humpback whale blows were visible through bigeyes 37km away in Beaufort Sea State (BSS) 2. This suggests the approach could be effective at detecting baleen and sperm whales from long distances, priority species under the U.S. Navy's Marine Species Monitoring Program. Systematic scans using bigeyes were performed in Guam over 20 days from a north-facing (193m) and a northeast-facing (157m) shore station in May 2014 and March 2015. These two sites were chosen because of mostly unobstructed views of the ocean, as well as generally high BSS that prohibit visual surveys from small vessels in this area. A SnapZoom digiscoping adapter, equipped with an iPhone or GoPro, was attached to the bigeye eyepiece allowing collection of photos and video, complementing supertelephoto (500-800mm) photography on a DSLR to assist with species confirmation. Observers recorded 33 odontocete sightings comprised of 4 confirmed species (spinner and bottlenose dolphins, pilot and melon-headed whales), but no baleen or sperm whales were observed. Several sightings were distant from shore, including two unidentified dolphins observed 9 km offshore in BSS 6, cued by diving birds, and a group of 160 melon-headed whales 14km offshore in BSS 5. The species observed and the sighting rate of 0.28 per hour, or 1.7 per day, were comparable to results from smallvessel surveys in Guam, suggesting an overall low density of marine mammals, and large whales in particular, during this time of year. These results demonstrate that shore-based surveys can provide an alternative means of surveying an area where use of other research platforms are impractical or cost prohibitive.

In the Pacific the Marine Mammal Monitoring on Navy Ranges (M3R) program maintains systems that continuously run algorithms to detect, classify and localize marine mammals year-round on the U.S. Navy’s deep-water Southern California Antisubmarine Warfare Range (SOAR) in Southern California and Pacific Missile Range Facility (PMRF) off Kauai, Hawai’i. Long-term archive data collected on these ranges allows for numerous types of studies on species inhabiting the ranges, including the monitoring of abundance and distribution, behavioral responses to naval activities, and habitat usage. They also provide the opportunity to study ambient noise and soundscapes.

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 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

This report presents the results of the Guam and Saipan Marine Species Monitoring: Winter-Spring Survey conducted on the motor vessel (M/V) Sea Fantasy (Guam survey) and the M/V Super Emerald (Saipan survey) from 15 to 29 March 2012. The objective of the 2012 survey effort was to conduct baseline surveys to further document marine mammal and sea turtle occurrence in nearshore waters around the island of Guam and Saipan. The approach primarily followed opportunistic survey protocols used in recent surveys around Guam (Ligon et al. 2011; HDR 2011), which remained within 10 kilometers (km) or 5.4 nautical miles (NM) of the coastline.

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.

This report summarizes the results of satellite-tagging efforts conducted before Submarine Command Course (SCC) training events in August 2021 and 2022, at the Pacific Missile Range Facility (PMRF) off the island of Kauaʻi. Researchers tagged 21 delphinids to observe their behavior before, during, and after the SCCs, to estimate received levels (RLs) of mid-frequency active sonar (MFAS).

In August 2023 and February 2024, Cascadia Research Collective (CRC) conducted small boat-based satellite tagging of odontocetes at the Pacific Missile Range Facility (PMRF), with acoustic support from Naval Information Warfare Center (NIWC) Pacific and Naval Undersea Warfare Center (NUWC) Newport, directing the tagging boat towards locations of acoustic detections on the range. Seventeen days of tagging effort were conducted over the two years during the biannual Submarine Command Course (SCC) training events. In total 19 odontocetes were tagged: 14 short-finned pilot whales (Globicephala macrorhynchus), 3 common bottlenose dolphins (Tursiops truncatus), 1 pantropical spotted dolphin (Stenella attenuata), and 1 melon-headed whale (Peponocephala electra). Additionally, 3 humpback whales (Megaptera noveangliae) were tagged in concert with this effort to test new tags, and that data was also analyzed herein

This report summarizes work conducted in FY2009-FY2010 with Navy support to characterize marine mammal sounds related to passive acoustic monitoring in the Hawaii Range Complex (HRC). Existing acoustic data from the Hawaii Range Complex area were analyzed to provide better descriptions of acoustic signals by species.

an effort to further develop a record of cetacean occurrence in the region, as well as to gather photos and biopsy samples and deploy satellite tags for population studies, the Pacific Islands Fisheries Science Center's (PIFSC) Cetacean Research Program (CRP) conducted surveys for cetaceans in the waters surrounding Guam and the CNМІ (Figure 1) during 2010-2014. This research was carried out in partnership with the U.S. Navy and is expected to continue through 2015. Detailed reports for each survey year were submitted to the Navy (Oleson and Hill 2010, Ligon et al. 2011, Hill et al. 2012, Hill et al. 2013).

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 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.

Goals: Understand species occurrence and distribution. Determine the population structure and abundance of the those species. Study the movements and habitat use of individuals and populations. Methods: Small boat-based and ship-based surveys. Passive acoustic recordings (HARPs & towed array). Photo-ID, biopsy sampling, and satellite tagging.

Melon-headed whales (Peponocephala electra) are found throughout the tropics, primarily in pelagic waters but with some being found near-shore around oceanic islands. This species is considered to be sensitive to sound, with one nearmass stranding event in Hawaiian waters associated with a naval exercise. However, relatively little is known of the acoustic behavior of this species. Here we combine multiple passive acoustic tools, including suction-cup attached acoustic tags (DTAGs) and a broadband recorder, the DMON, to gather baseline, broadband bioacoustic behavior data for melon headed whales. Further, two distinct melon-headed populations are compared: the Kohala resident population (KRP) and the Hawaiian Islands population (HIP). DMONs recorded from a towfish and drifter buoy setup. Three animals were tagged, two from the KRP population (estimated group sizes 280 and 350 ! individuals) and one from the HIP population (estimated group size of 350 individuals). In total, 1096 and 329 whistles have been identified from the KRP and HIP tag recordings, respectively. Analyses included spectral and temporal characteristics of the whistles, variability of these signals and whistle type categorizations. Data suggest variation between melon-headed whale populations in whistle duration (mean: KRP – 0.99 s; HIP – 0.75 s), start frequency (mean: KRP – 5.1 kHz; HIP – 5.8 kHz), end frequency (mean: KRP – 4.8 kHz; HIP – 11.5 kHz), peak frequency (mean: KRP – 5.5 kHz; HIP – 7.6 kHz), and centroid frequency (mean: KRP – 7.7 kHz; HIP – 10.1 kHz). No overlap in whistle type was apparent between or within populations, which suggests that individual animals may produce semi-stereotyped calls. These are the first broadband comparisons of melon-headed whale signals. The whistle characterization differences suggest automatic detection and classification algorithms can be used to identify melon-headed whales in Hawaiian waters.

In this assessment we incorporated published and unpublished information to delineate and score Biologically Important Areas (BIAs) for cetaceans in the Hawaiʻi region following standardized criteria. Twenty-six cetacean species have been documented in Hawaiʻi. Eleven odontocete species have distinct small populations resident to one or more island areas: rough-toothed dolphins, pantropical spotted dolphins, common bottlenose dolphins, spinner dolphins, short-finned pilot whales, false killer whales, pygmy killer whales, melon-headed whales, Blainville’s beaked whales, Cuvier’s beaked whales, and dwarf sperm whales.

We have been conducting ongoing monthly aerial surveys off Cape Hatteras, NC, USA as part of the US Navy's marine species monitoring program in the Atlantic since 2011. We utilize line transect survey methods and extensively photograph all sightings to confirm species identification. Survey tracklines extend from shallow continental shelf waters, across the shelf break, to deep pelagic waters. From May 2011 through December 2014, 26,131km of trackline were flown, and 9,941 individual cetaceans were documented during 437 encounters. Nineteen species of cetaceans, including three mysticetes (Balaenoptera physalus, B. acutorostrata, Megaptera novaeangliae), five deep-divers (Physeter microcephalus, Kogia spp., Ziphius cavirostris, Mesoplodon europaeus, M. mirus), and eleven delphinids (Tursiops truncatus, Stenella frontalis, S. attenuate, S. coeruleoalba, S. clymene, S. longirostris, Steno bredanensis, Peponocephala electra, Lagenodelphis hosei, Grampus griseus and Globicephala macrorhynchus) were encountered. Similar surveys at the adjacent Onslow Bay, NC site yielded only 257 sightings (4,773 individuals representing nine species) despite nearly two times the survey effort flown (48,698km). At Cape Hatteras, minimum abundance estimates (i.e. uncorrected for availability or perception bias) were generated using spatio-temporal density surface modelling for species with sufficient detections. Predicted monthly abundance of T. truncatus varied between 170 (95% confidence interval; 0 - 17,100) and 3,450 (300 - 8,510). Monthly Stenella spp. abundance varied between 110 (0 - 360) and 1,720 (400 - 5,390). Monthly abundance of G. macrorhynchus varied between 10 (0 - 960) and 1,230 (220 - 4,300). These results demonstrate that the waters off Cape Hatteras support both higher diversity and density of cetaceans than adjacent waters along the US Atlantic coast. This site is included in the area of interest identified in six pending permits for large-scale, commercial seismic surveys. We suggest that the high density and diversity of cetaceans at this site warrants a special degree of concern by the US Bureau of Ocean Energy Management.

This is the fifth progress report of a monitoring program for protected marine species in waters offshore Cape Hatteras and Onslow Bay, North Carolina and Jacksonville, Florida. The results of aerial line transect surveys and vessel-based photo-ID surveys and passive acoustic monitoring are reported for the period from January 2012 through December 2012.

Aerial surveys of marine mammals were performed as part of the Marine Mammal Monitoring on Navy Undersea Acoustic Ranges (3MR) program. Surveys were performed in three regions: a) Pacific Missile Range Facility (PMRF), Barking Sands, Kauai (BSURE and BARSTUR ranges; Jul 12-Nov 17, 2002); b) Bahamas (Northwest Providence Channel and AUTEC range; Jan 4-12, 2003); and c) main Hawaiian Islands (Feb 21–Apr 5, 2003). The mission was to identify species and record positions and composition of all marine mammal pods sighted. These data were made available to co-investigators (Martin and Moretti) of the 3MR program in order to correlate the visual positions with acoustic localizations using Navy assets. All surveys were flown in a twin-engine Partenavia aircraft at 100 knots airspeed and 244 m altitude. Four personnel participated on each flight including one observer on each side of the aircraft, data recorder and pilot. Methods used were consistent with those of modern distance sampling theory.

In 2015 field efforts were carried out at the U.S. Navy’s Atlantic Undersea Test and Evaluation Center (AUTEC) during two time periods prior to the spring and fall Submarine Commander Courses (SCC). The tests were conducted under the auspice of the Living Marine Resources Program (LMR) and the Office of Naval Research (ONR). The first took place April 23rd – May 11th, and the second October 24th – November 6th. There was an additional test conducted from August 10th – 23rd when range activity was low and weather conditions are generally better, thus maximizing the opportunities for locating and tagging beaked whales to gather baseline data.

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 covers a number of activities carried out by the Cetacean Research Program (CRP) at the Pacific Islands Fisheries Science Center (PIFSC) in 2009 and 2010 supported with partial funding from U.S. Navy Pacific Fleet (PACFLT). The report is intended to provide preliminary data and results from 4 survey efforts between Hawaii and Guam in early 2010.

The goal of this initial phase is to process and compile available data from visual surveys performed by both contractor‐led efforts as well as Navy in‐house ones, such that: 1. A GIS‐based summation of all survey tracks could be visualized 2. A geo‐referenced database of sightings can be queried to visualize sightings by species or survey variables such as observer platform, sea state, or season

The University of Hawai‘i Health and Stranding Lab (HSL), located in Kaneohe Bay, is the only entity in the Pacific Islands region that responds to strandings, conducts necropsy and cause of death investigations, archives tissues and performs research to identify and evaluate threats to Pacific Island cetaceans. The purpose of this project has three objectives: 1) To conduct comprehensive stranding investigations for high priority species through increased capacity for in-house diagnostics; 2) To analyze archived tissues for the presence of two pathogens (circovirus and morbillivirus) and to examine the detectability of Toxoplasma positive animals over time and 3) To conduct analyses of historical stranding patterns and causes of mortality that incorporate quantitative estimates of stranding date and advanced diagnostic information.

This review examines historical data from 535 odontocete stranding events in the Mariana archipelago and Hawaiian Islands by date, location and species and spans the time period of 1848 to 2023. Reports of strandings increased across the two geographic regions that were generally consistent over time. A total of 54 historical stranding events that represent 14 odontocete species are described for the Mariana Islands. A total of 481 stranding events that represent 19 odontocete species are described from the Hawaiian Islands, significantly updating the last published report that examined 202 odontocete strandings that occurred in the main Hawaiian Islands between 1937 and 2002. ArcGIS cluster maps were utilized to identify groupings of stranding events across the geographic regions. The majority of strandings in the Mariana Islands were reported from the west and southeastern coast of Guam, followed by Saipan, Rota and Tinian. Stranding hotspots in the Hawaiian Islands were identified at Mā’alaea Bay, Maui, at windward Oʻahu and near Kailua-Kona on Hawaiʻi Island.

We report significant pathological findings from 250 stranding investigations of 20 cetacean species in the Pacific Islands region between 2006 and 2022. Full or partial necropsies of 196 of the 250 stranding cases (78.4%) resulted in a diagnosis or multiple diagnoses associated with death in 126 cases. Natural disease accounted for 60.3% of stranded animals; approximately half were in poor body condition at time of death due to chronic illness. Morbillivirus and Brucella sp. infections caused mortality in eleven species, including striped dolphins and the Longman’s beaked whale. Toxoplasma infection, of anthropogenic cause in Hawaiʻi, led to the deaths of two spinner dolphins. Pygmy and dwarf sperm whales, beaked whales and pilot whales showed heavy parasitism by nematodes, cestodes and trematodes. Approximately 12.7% of stranded individuals were perinates/neonates, with three cases of dystocia with maternal mortality. Anthropogenic trauma was observed in 30.2% of strandings. In seven Cuvier’s beaked whales, cranial and/or microvascular hemorrhages were categorized as trauma. Vertebral and skull fractures were attributed to direct vessel strikes for two pygmy sperm whales, a Cuvier’s beaked whale, a humpback whale calf and a striped dolphin. Blast trauma was observed in three Fraser’s dolphins that were part of an uncommon stranding event. Significant plastic debris, and/or fishery debris were found in stomachs of six species and fatal fishhook penetration occurred in a Submitted in Support of the U.S. Navy’s 2023 Annual Marine Species Monitoring Report for the Pacific STANDARD FORM 298 Back (Rev. 8/98) bottlenose dolphin. This study highlights the value of carcass examinations in a region inhabited by small island associated populations where carcass recovery rates are low, and cetaceans face an array of natural and anthropogenic threats.

This project provides financial 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. Cetacean stranding 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 established relationships with partners throughout the region and the mounting of an immediate response to each newly reported stranding event that occurs. The UH Health and Stranding Lab conducts 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. Progress associated with the project option in support of the marine debris analyses has been prepared for peer-reviewed publication in the journal Marine Pollution Bulletin. These findings are described separately from the base tasks and fecal hormones option in the attached manuscript draft.

Adults of many free-ranging delphinid species cannot be reliably sexed at sea. Sexually mature, known-sex adult short-finned pilot, pygmy killer, melon-headed, and false killer whales were profiled from at-sea photos to assess proportional fin and body dimorphism. Males of all four species had larger dorsal fins proportional to anterior body length. False killer whales showed no further dimorphism, while melon-headed whales showed subtle dimorphism in dorsal fin overhang. Pygmy killer whales showed subtle dimorphism in lateral positioning of the top-most point and overhang. Lastly, short-finned pilot whales showed strong dimorphism in the leading edge, lateral positioning of the top-most point, and height of the overhang. Generalized linear models showed strong predictive accuracy for pilot and false killer whales, and moderate accuracy for pygmy killer and melon-headed whales. Results indicate that adult short-finned pilot and false killer whales can be accurately sexed in the field or via morphometrics. Adult pygmy killer and melon-headed whales have subtle sexual dimorphism that can be detected using morphometrics. The presence of dimorphism gives insight into potential reproductive strategies and social structure. Further analysis is needed to explore morphometric differences between inshore and pelagic populations of these species, as well as ontogenetic growth between life stages.

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.