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The mammalian brain is characterized by high energy expenditure and small energy reserves, making it dependent on continuous vascular oxygen and nutritional supply. The brain is therefore extremely vulnerable to hypoxia. While neurons of most terrestrial mammals suffer from irreversible damage after only short periods of hypoxia, neurons of the deep-diving hooded seal (Cystophora cristata) show a remarkable hypoxia-tolerance. To identify the molecular mechanisms underlying the intrinsic hypoxia-tolerance, we excised neurons from the visual cortices of hooded seals and mice (Mus musculus) by laser capture microdissection. A comparison of the neuronal transcriptomes suggests that, compared to mice, hooded seal neurons are endowed with an enhanced aerobic metabolic capacity, a reduced synaptic transmission and an elevated antioxidant defense. Publicly available whole-tissue brain transcriptomes of the bowhead whale (Balaena mysticetus), long-finned pilot whale (Globicephala melas), minke whale (Balaenoptera acutorostrata) and killer whale (Orcinus orca), supplemented with 2 newly sequenced long-finned pilot whales, suggest that, compared to cattle (Bos taurus), the cetacean brain also displays elevated aerobic capacity and reduced synaptic transmission. We conclude that the brain energy balance of diving mammals is preserved during diving, due to reduced synaptic transmission that limits energy expenditure, while the elevated aerobic capacity allows efficient use of oxygen to restore energy balance during surfacing between dives. [ABSTRACT FROM AUTHOR]

Three killer whale ecotypes are found in the Northeastern Pacific: residents, transients, and offshores. These ecotypes can be discriminated in passive acoustic data based on distinct pulsed call repertoires. Killer whale acoustic encounters for which ecotypes were assigned based on pulsed call matching were used to characterize the ecotype-specific echolocation clicks. Recordings were made using seafloor-mounted sensors at shallow (∼120 m) and deep (∼1400 m) monitoring locations off the coast of Washington state. All ecotypes' echolocation clicks were characterized by energy peaks between 12 and 19 kHz, however, resident clicks featured sub peaks at 13.7 and 18.8 kHz, while offshore clicks had a single peak at 14.3 kHz. Transient clicks were rare and were characterized by lower peak frequencies (12.8 kHz). Modal inter-click intervals (ICIs) were consistent but indistinguishable for resident and offshore killer whale encounters at the shallow site (0.21–0.22 s). Offshore ICIs were longer and more variable at the deep site, and no modal ICI was apparent for the transient ecotype. Resident and offshore killer whale ecotype may be identified and distinguished in large passive acoustic datasets based on properties of their echolocation clicks, however, transient echolocation may be unsuitable in isolation as a cue for monitoring applications. [ABSTRACT FROM AUTHOR]

In this paper, we study the hierarchy sensitivity of Protvino to ORCA (P2O) experiment in three flavour scenario as well as its sensitivity to non-standard interactions (NSI) in neutrino propagation. Because of the largest possible baseline length of 2595 km, P2O is expected to have strong sensitivity towards neutrino mass hierarchy and NSI parameters. In our study, we show that even though the number of appearance channel events for the minimal configuration of P2O are higher compared to DUNE, still the hierarchy sensitivity of P2O is less than DUNE because of large background events. Our results show that for a background reduction factor of 0.46 and appearance channel background systematic normalization error of 4%, the hierarchy sensitivity of P2O becomes equivalent of DUNE for δCP = 195°. We call this configuration of P2O as optimized P2O. Regarding the study of NSI, we find that, for ϵeμ (ϵeτ) sensitivity of DUNE is similar (better) as compared to optimized P2O when both ϵeμ and ϵeτ are included in the analysis. Our results show that in presence of NSI, the change of hierarchy sensitivity with respect to standard three flavor scenario, is higher in P2O as compared to DUNE. Further, hierarchy sensitivity in presence of NSI is lower (higher) than sensitivity in the standard three flavour scenario for δCP = 270°(90°). It is important to note that hierarchy sensitivity of optimized P2O does not get significantly better than DUNE for the current favourable values of δCP which is 180° < δCP< 360° as obtained by the global analysis in both standard three flavour and in presence of NSI. [ABSTRACT FROM AUTHOR]

• A new instrument to the observation of cosmic rays on Antarctic Peninsula. • Able to detect neutrons, muons and muon incident directions. • It fills a gap in the worldwide network of neutron monitors. • To analize solar activity and the interaction between cosmic rays and atmosphere. ORCA, from the Spanish name Observatorio de Rayos Cósmicos Antártico , is a cosmic ray detector devoted to the observation of secondary cosmic rays at Juan Carlos I Spanish Antarctic Base (62 ° 39 ′ 46 ″ S , 60 ° 23 ′ 20 ″ W , 12 m above sea level). ORCA was installed at the beginning of January 2019 after performing a latitudinal survey from Vigo (Spain) to Livingston Island aboard the Sarmiento de Gamboa Research Vessel. ORCA was in commissioning phase from January 2019 to March 2020, being in normal operation mode from March 2020. A vertical cutoff rigidity of 2.37 GV has been computed at ORCA location and during the first year of operation, i. e. from March 2020 to March 2021. ORCA consists of three detectors stacked in a shared structure that maintains the relative distances between the detectors. A muon telescope (ORCM), a neutron monitor without any shielding around (ORCB) and a 3NM64 neutron monitor (ORCA). This configuration allows the measurement of neutron count rates at two different energy thresholds, muon count rate and muon incident directions. Measurements recorded during the first year of operation and ORCA potential capabilities are shown in this work. [ABSTRACT FROM AUTHOR]

Using PREM as a reference model for the Earth density distribution we investigate the sensitivity of ORCA detector to deviations of the Earth (i) outer core (OC) density, (ii) inner core (IC) density, (iii) total core density, and (iv) mantle density, from their respective PREM densities. The analysis is performed by studying the effects of the Earth matter on the oscillations of atmospheric ν μ , ν e , ν ¯ μ and ν ¯ e . We present results which illustrate the dependence of the ORCA sensitivity to the OC, IC, core and mantle densities on the type of systematic uncertainties used in the analysis, on the value of the atmospheric neutrino mixing angle θ 23 , on whether the Earth mass constraint is implemented or not, and on the way it is implemented, and on the type – with normal ordering (NO) or inverted ordering (IO) – of the light neutrino mass spectrum. We show, in particular, that in the "most favorable" NO case of implemented Earth mass constraint, "minimal" systematic errors and sin 2 θ 23 = 0.58 , ORCA can determine, e.g., the OC (mantle) density at 3 σ C.L. after 10 years of operation with an uncertainty of (− 18%)/+ 15% (of (− 6%)/+ 8%). In the "most disfavorable" NO case of "conservative" systematic errors and sin 2 θ 23 = 0.42 , the uncertainty on OC (mantle) density reads (− 43%)/+ 39% ((− 17%/+ 20%), while for for sin 2 θ 23 = 0.50 and 0.58 it is noticeably smaller: (− 37)%/+ 30% and (− 30%)/+ 24% ((− 13%)/+ 16% and (− 11%/+ 14%)). We find also that the sensitivity of ORCA to the OC, core and mantle densities is significantly worse for IO neutrino mass spectrum. [ABSTRACT FROM AUTHOR]

Mucorales infections are increasing in frequency and are a One Health pathogen of concern. In humans and domestic animals, risk factors include being immunocompromised, elevated circulating serum iron, contaminated open wounds, or metabolic diseases such as ketoacidosis or uncontrolled diabetes. Mucormycosis was first identified in 2012 in Pacific Northwest marine mammals, predominantly in harbor porpoises. We performed an assessment to determine the overall qualitative risk, or risk score, of mucormycosis in harbor porpoises. Risk factors for this disease are unknown in aquatic mammals. In a separate risk factor analysis, potential risk factors such as pollutants, trace metals (e.g., iron), and co-infection with other pathogens (e.g., viruses and Brucella spp.) were examined in mucormycosis cases and noncases using a matched case-control study design, to determine the presence and strength of association of these factors with mucormycosis. Disease severity (gross and histopathology) and exposure scores were multiplied together to obtain the overall risk scores of 9 -16 which corresponded to moderate and severe, respectively. In the risk factor analysis, the factors most strongly associated with a mucormycosis case, relative to a control, were elevated liver iron, decreased blubber thickness, and the decreased ratio of the sum of PCB congeners/sum of PBDE congeners. The results of this study suggest that mucormycosis may pose an inordinately high risk to harbor porpoises (and potentially sympatric species in the Salish Sea such as southern resident killer whales) based on the detected prevalence and the severity of lesions observed at necropsy. However, the risk may be greater on an individual basis compared to the overall population, and is likely related to other factors such as increased POP and heavy metal burdens.

Environmental enrichment is critical for maintaining cognitive welfare for animals in human care but is subject to individual preferences.  The interest in a video-based enrichment was assessed for a single killer whale (Orcinus orca) in human care.  The adult female was presented 20 video recordings featuring cetaceans, elephants, or humans with each video presented in two conditions: (1) with sound and (2) without sound.  Four additional presentations in which the television displayed a blank screen served as controls.  All sessions were videotaped and coded for time spent viewing the recordings, behavioral responses, and visual laterality.  The killer whale spent significantly more time at the television when programs were on screen compared to when the television was present but blank.  She was more likely to watch videos accompanied by sound than those presented without sound. Videos were more likely to be viewed monocularly rather than binocularly, with a right eye preference when viewing the videos the first time they were presented.  The highest rates of behavioral responses occurred during videos of cetaceans.  These results demonstrate that one killer whale responded to video recordings of different stimuli, suggesting that video recordings may be used as a form of enrichment for cetaceans and that not all video content and formats are equally interesting.

In Gansbaai (South Africa), at Dyer Island Nature Reserve, a large White shark population is present and can be observed due to the support of local ecotourism operators authorised to reach the field observation sites. Between 2009 and 2019, it was possible to create a database including information about each individual observed. In total, 423 white sharks were sighted during 462 direct observation hours from the boat, that included 220 hours from the diving “cage”. The mean sighting rate was 0.91 (range 0.18–1.53) sharks per hour and sighting rates dramatically declined in the last three years of the study period. Ninety-nine unique Photo-Ids of the dorsal fin were collected and only five re-sightings occurred, which indicate a transient behaviour for the Gansbaai White shark population. The sex ratio showed that females were always prevalent over males throughout the duration of the observations: the ratios were 1:2.2:0.8 for males, females, and unsexed sharks, respectively, and showed the prevalence of immature female individuals (immature: 51 males, 201 females, and 40 unsexed; adults: 49 males, 14 females, and 1 unsexed; undefined maturity: 5 males, 19 females, and 43 unsexed sharks). The predominance of immatures only applies to the females; there were as many immature males (51) as mature (49). The total length for all the individuals was between 150 cm and 500 cm (mean 308 cm, n = 423) with few young-of-the-year and adults recorded, indicating that Gansbaai Area is not a nursery area nor an adult aggregation site, but a seasonal feeding ground. The interannual sighting trend showed a consistent long-term increasing peak (ca. 4–5 years) and this could confirm that, in Gansbaai, the White shark frequency is not affected by ecotourism but, since 2017, a consistent loss of sightings was also due to recorded transient killer whales’ unusual fatal attacks.

Pacific salmon (Oncorhynchus spp.) are important to the ecology, economy, and cultures of the Pacific Northwest. Many populations of Pacific salmon in the Pacific Northwest are declining because of poor marine survival. We evaluated the role of Steller (Eumetopias jubatus) and California (Zalophus californianus) sea lions as predators of Pacific salmon. Roughly, half of the 1330 metric tons (t) of Pacific salmon eaten by Steller sea lions per year and of the 1220 t of Pacific salmon eaten by California sea lions per year in northwest Washington during 2010-2013 were coho salmon (O. kisutch). The response of Steller and California sea lions to the large run of pink salmon (O. gorbuscha) in 2011 was less than expected. Sea lions of these species rarely ate large (roughly ≥50 cm in total length) Chinook salmon (O. tshawytscha), indicating that they have limited direct competition for prey with the southern resident distinct population segment of killer whales (Orcinus orca). Combined, California and Steller sea lions in northwest Washington consumed a mass of coho salmon similar to that landed by commercial fisheries in Washington State. More work on modeling the effect of the predation by California and Steller sea lions on salmon populations, particularly for coho salmon, is needed to better evaluate the conservation and productivity of Pacific salmon. [ABSTRACT FROM AUTHOR]

The Arctic Ice Monitoring (AIM) observatory has been maintained on the Chukchi Plateau at 75.1° N 168.0° W nearly continuously since 2003. The AIM site consists of a submerged mooring that, since October 2008, has been instrumented with a passive acoustic recorder to sample ambient sound, with a focus on marine mammal detections in the High Arctic. Year-long data sets for 2009, 2012, and 2014–2020 were analyzed for the presence of signals from Arctic species including bowhead and beluga whales, bearded seals, and walrus. Calls from subarctic ribbon seals were commonly detected in autumn months, suggesting they have expanded their distribution much further northward. Killer whale calls were detected in recent years providing evidence that they have moved further north into the Pacific Arctic. No other subarctic cetaceans were heard. Year-round passive acoustic sampling of sounds produced by marine mammals over a decadal timescale has enhanced our understanding of how climate-driven changes in biodiversity are affecting even the very High Arctic. [ABSTRACT FROM AUTHOR]

The KM3NeT research infrastructure is unconstruction in the Mediterranean Sea. KM3NeT will study atmospheric and astrophysical neutrinos with two multi-purpose neutrino detectors, ARCA and ORCA, primarily aimed at GeV–PeV neutrinos. Thanks to the multi-photomultiplier tube design of the digital optical modules, KM3NeT is capable of detecting the neutrino burst from a Galactic or near-Galactic core-collapse supernova. This potential is already exploitable with the first detection units deployed in the sea. This paper describes the real-time implementation of the supernova neutrino search, operating on the two KM3NeT detectors since the first months of 2019. A quasi-online astronomy analysis is introduced to study the time profile of the detected neutrinos for especially significant events. The mechanism of generation and distribution of alerts, as well as the integration into the SNEWS and SNEWS 2.0 global alert systems, are described. The approach for the follow-up of external alerts with a search for a neutrino excess in the archival data is defined. Finally, an overview of the current detector capabilities and a report after the first two years of operation are given. [ABSTRACT FROM AUTHOR]

Examining Eastern North Pacific gray whale (Eschrichtius robustus) carcasses and tracking mortality and morbidity are essential for assessing the health of this stock. In the eastern Chukchi Sea, the expansive coastline relative to few coastal communities makes monitoring for and physical examination of gray whale carcasses difficult. The Aerial Surveys of Arctic Marine Mammals (ASAMM) project offers an unparalleled dataset of gray whale carcasses, documented and photographed from July to October 2009–2019, providing a unique opportunity to investigate imaged gray whale carcasses for possible cause of death. Surveys covered expanses of gray whale and killer whale (Orcinus orca) summer and autumn habitat. ASAMM documented a total of 59 gray whale carcasses, distributed across the eastern Chukchi Sea (67.5° N–72.0° N, 155.5° W–169.0° W). Carcass sighting rates ([CPUE] carcasses per 1000-km of effort) varied by month and year. The highest numbers of carcasses were observed in 2012 (13) and 2019 (8). August had the highest number of gray whale carcass sightings (22) and the highest carcass sighting rate (0.231 CPUE). Images were obtained for 56 gray whale carcasses. The majority (41) of imaged gray whale carcasses had injuries consistent with probable killer whale predation, and were photo-documented every year except 2010 (when no carcasses were seen) and 2011. Eight carcasses were suspect killer whale predation, and cause of death could not be determined for seven carcasses. These results will be valuable for evaluating mortality, concurrent with rapid oceanographic changes, and increases in anthropogenic activities. [ABSTRACT FROM AUTHOR]

Female humpback whale (Megaptera novaeangliae) reproductive class and male-female interactions during the breeding season [Doctoral dissertation]. However, note that the dive behavior of PE2 and SE4 is still correlated through 13:20 even though the animal was not visually sighted again, and that both PE2 and SE4 surfaced at 13:02 at the same time as the female. Humpback whale competitive group behavior on breeding grounds was first described in the early 1980s (Baker & Herman, 1984; Mobley & Herman, 1985; Tyack & Whitehead, 1982), and has been found to be consistent across breeding grounds and ocean basins. Quantifying the behavior of humpback whales (Megaptera novaeangliae) and potential responses to sonar. [Extracted from the article]

Continued monitoring of body condition and hormone levels of this gray whale population will generate "health profiles" of individual whales, enabling assessment of change over time and potential identification and diagnosis for variations in population health. Hence, to increase our sample size for correlation analysis, we used BAI values measured within ± 14 days of a fecal sample collection from the same individual as gray whales do not significantly change their body condition within a period of two weeks (paired I t i -test using all BAI values of individuals assessed within 14 days in 2016, 2017, and 2018: I n i = 61, I p i =.86, I df i = 60, I t i = -0.174). In this study, we employed simultaneous multidisciplinary techniques to investigate the effects of body condition variability on hormones associated with stress (i.e., cortisol) and energy allocation (i.e., cortisol and thyroid hormones) in Eastern North Pacific (ENP) gray whales ( I Eschrichtius robustus i ). Conversely, the random factor of whale identity highly contributed to the Tm model ( I R i SP 2 sp c = 0.522, I R i SP 2 sp m = 0.835; Table 2). 2 TABLELinear mixed model selection parameters of gray whale glucocorticoid metabolite (GCm) and thyroid metabolite (Tm) concentrations relative to Body Area Index (BAI), sex, year, and day of the year (DOY). [Extracted from the article]

At the same time, this is also the first confirmed movement of killer whales from Iceland to Spain, Italy, and Lebanon, and the first documented account of killer whales in Lebanese waters. Killer whales ( I Orcinus orca i , Linnaeus 1758) are apex predators that are widely distributed throughout the world's oceans (Forney & Wade, 2006), and can travel over large distances. This has been the case for the Strait of Gibraltar killer whale population (Ruth Esteban, personal communication, December 2019), killer whales of the Azores (Laura González García, personal communication, January 2020; Rui Peres dos Santos, personal communication, January 2020), and killer whales from Scottish waters (A.S., personal observation). Long-distance movements of North Atlantic killer whales (Orcinus orca) from Iceland via Spain and Italy to Lebanon. [Extracted from the article]

Documented cases of cetacean births in the wild are rare. While there are currently no direct observations of a complete humpback whale birth, they are one of the few large whale species where observers have been present during a birthing event. We compiled eye‐witnessed accounts of all known humpback whale birthing events and found nine well‐documented cases globally (three published and six "new" unpublished). In two‐thirds of the accounts another "escort" whale was present and in close association with the birthing female, and of these, most cases involved multiple escorts (n = 4). We describe details of birthing events, including mother, neonate and escort(s)' behavior, neonate appearance, and discuss reasons for escort presence during parturition. We note that immediately postpartum: (1) blood and/or placenta were not always apparent during above water observations, (2) females often (but not always) supported calves at the surface, (3) constant travel and tail slapping were typical neonate behaviors, (4) two cases of temporary calf abandonment (<10 min), and (5) evidence of shark scavenging (of placenta) and possible predation attempts (of neonate). Lastly, we suggest curled tail flukes as an additional trait for identifying neonates and note that fetal folds are not always evident in newborn humpback whales. [ABSTRACT FROM AUTHOR]

As human activities impact virtually every animal habitat on the planet, identifying species at-risk from disturbance is a priority. Cetaceans are an example taxon where responsiveness to anthropogenic noise can be severe but highly species and context specific, with source-receiver characteristics such as hearing sensitivity only partially explaining this variability. Here, we predicted that ecoevolutionary factors that increase species responsiveness to predation risk also increase responsiveness to anthropogenic noise. We found that reductions in intense-foraging time during exposure to 1- to 4-kHz naval sonar and predatory killer whale sounds were highly correlated (r = 0.92) across four cetacean species. Northern bottlenose whales ceased foraging completely during killer whale and sonar exposures, followed by humpback, long-finned pilot, and sperm whales, which reduced intense foraging by 48 to 97%. Individual responses to sonar were partly predicted by species-level responses to killer whale playbacks, implying a similar level of perceived risk. The correlation cannot be solely explained by hearing sensitivity, indicating that species- and context-specific antipredator adaptations also shape cetacean responses to human-made noise. Species that are more responsive to predator presence are predicted to be more disturbance sensitive, implying a looming double whammy for Arctic cetaceans facing increased anthropogenic and predator activity with reduced ice cover. [ABSTRACT FROM AUTHOR]

The article presents the discussion on Humpback whales (Megaptera novaeangliae) being cosmopolitan and highly migratory animals. Topics include found in all ocean basins and annually migrating between low-latitude waters; and growing evidence of humpback whales feeding during typical migration months being reported for non-migrant individuals.

An exploration task can be performed by a team of mobile robots more efficiently than human counterparts. They can access and give live updates for hard-to-reach areas such as a disaster site or a sewer. However, they face some issues hindering them from optimal path planning due to the symmetrical shape of the environments. Multiple robots are expected to explore more areas in less time while solving robot localization and collision-avoidance issues. When deploying a multi-robot system, it is ensured that the hardware parts do not collide with each other or the surroundings, especially in symmetric environments. Two types of methods are used for collision avoidance: centralized and decentralized. The decentralized approach has mainly been used in recent times, as it is computationally less expensive. This article aims to conduct a systematic literature review of different collision-avoidance strategies and analyze the performance of innovative collision-avoidance techniques. Different methods such as Reinforcement Learning (RL), Model Predictive Control (MPC), Altruistic Coordination, and other approaches followed by selected studies are also discussed. A total of 17 studies are included in this review, extracted from seven databases. Two experimental designs are studied: empty/open space and confined indoor space. Our analysis observed that most of the studies focused on empty/open space scenarios and verified the proposed model only through simulation. ORCA is the primary method, against which all the state-of-the-art techniques are evaluated. This article provides a comparison between different methods used for multi-robot collision avoidance. It discusses if the methods used are focused on safety or path planning. It also sheds light on the limitations of the studies included and possible future directions. [ABSTRACT FROM AUTHOR]

Long-term passive acoustic monitoring of cetaceans is frequently limited by the data storage capacity and battery life of the recording system. Duty cycles are a mechanism for subsampling during the recording process that facilitates long-term passive acoustic studies. While duty cycles are often used, there has been little investigation on the impact that this approach has on the ability to answer questions about a species' behavior and occurrence. In this study, the effects of duty cycling on the acoustic detection of southern resident killer whales (SRKW) (Orcinus orca) were investigated. Continuous acoustic data were subsampled to create 288 subsampled datasets with cycle lengths from 5 to 180 min and listening proportions from 1% to 67%. Duty cycles had little effect on the detection of the daily presence of SRKW, especially when using cycle lengths of less than an hour. However, cycle lengths of 15–30 min and listening proportions of at least 33% were required to accurately calculate durations of acoustic bouts and identify those bouts to ecotype. These results show that the optimal duty cycle depends on the scale of the research question and provide a framework for quantitative analysis of duty cycles for other marine species. [ABSTRACT FROM AUTHOR]

Trend analysis can provide valuable information about marine mammal population dynamics, potentially revealing the influence of environmental factors and inform conservation and management decisions. We reviewed the marine mammal stock assessment reports (SARs) published by the US National Marine Fisheries Service and found that 80% of the selected 244 marine mammal stocks with SARs lack assessment for trends in population abundance. We compared trend analysis with another common management tool, potential biological removal (PBR), a measure of the maximum human‐caused mortality that can still result in positive population growth. We found that, generally, estimates of PBR were lower for declining stocks than for increasing or stable stocks and varied by life history characteristics. As a case study, we used a resampling approach on three well‐studied stocks, killer whale (Orcinus orca—Northern Resident), beluga (Delphinapterus leucas—Cook Inlet), and humpback whale (Megaptera novaeangliae—CA/OR/WA), to test the minimal amount of time and sampling necessary to detect population trends with high statistical power. We found seven sampling events over more than 10 years were needed for a high statistical power level for all three stocks. Altogether, these findings suggest that well‐studied stocks can provide crucial information on the statistical requirements for detecting trends. Furthermore, our proposed resampling approach might enable more frequent trend analysis, even with limited time series available for many stocks. [ABSTRACT FROM AUTHOR]

Although four species of odontocete and four species of baleen whale have been recorded in Prydz Bay, their vocalizations have been rarely investigated. Underwater vocalizations were recorded during March 2017 in Prydz Bay, Antarctica. Bio-duck sounds, downsweeps, inverted "u" shape signals, whistles, pulsed sounds, and broadband clicks were recorded. Bio-duck sounds and downsweeps were associated with Antarctic minke whales (Balaenoptera bonaerensis) based on visual observations. Similarities between inverted "u" shape signals, biphonic calls, and clicks with vocalizations previously described for killer whales (Orcinus orca) lead us believe the presence of Antarctic killer whales. According to sound structures, signal characteristics, and recording location, Antarctic type C killer whales were the most probable candidates to produce these detected calls. These represent the first detection of inverted "u" shape signals in Antarctic waters, and the first report of Antarctic killer whale in Prydz Bay based on passive acoustic monitoring. The co-existence of Antarctic minke and killer whales may imply that minke whales can detect differences between the sounds of mammal-eating and fish-eating killer whales. Our descriptions of these underwater vocalizations contribute to the limited body of information regarding the distribution and acoustic behavior of cetaceans in Prydz Bay. [ABSTRACT FROM AUTHOR]

Data sets composed of sequences of curves sampled at high frequencies in time are increasingly common in practice, but they can exhibit complicated dependence structures that cannot be modelled using common methods in functional data analysis. We detail a hierarchical approach that treats the curves as observations from a hidden Markov model. The distribution of each curve is then defined by another fine‐scale model that may involve autoregression and require data transformations using moving‐window summary statistics or Fourier analysis. This approach is broadly applicable to sequences of curves exhibiting intricate dependence structures. As a case study, we use this framework to model the fine‐scale kinematic movements of a northern resident killer whale (Orcinus orca) off the western coast of Canada. Through simulations, we show that our model produces more interpretable state estimation and more accurate parameter estimates compared to existing methods. [ABSTRACT FROM AUTHOR]

Climate-driven changes are affecting sea ice conditions off Tasiilaq, Southeast Greenland, with implications for marine mammal distributions. Knowledge about marine mammal presence, biodiversity, and community composition is key to effective conservation and management but is lacking, especially during winter months. Seasonal patterns of acoustic marine mammal presence were investigated relative to sea ice concentration at two recording sites between 2014 and 2018, with one (65.6°N, 37.4°W) or three years (65.5°N, 38.0°W) of passive acoustic recordings. Seven marine mammal species were recorded. Bearded seals were acoustically dominant during winter and spring, whereas sperm, humpback, and fin whales dominated during the sea ice-free summer and autumn. Narwhals, bowhead, and killer whales were recorded only rarely. Song-fragments of humpback whales and acoustic presence of fin whales in winter suggest mating-associated behavior taking place in the area. Ambient noise levels in 1/3-octave level bands (20, 63, 125, 500, 1000, and 4000 Hz), ranged between 75.6 to 105 dB re 1 μPa. This study provides multi-year insights into the coastal marine mammal community composition off Southeast Greenland and suggests that the Tasiilaq area provides suitable habitat for various marine mammal species year-round. [ABSTRACT FROM AUTHOR]

Highly social top marine predators, including many cetaceans, exhibit culturally learned ecological behaviours such as diet preference and foraging strategy that can affect their resilience to competition or anthropogenic impacts. When these species are also endangered, conservation efforts require management strategies based on a comprehensive understanding of the variability in these behaviours. In the northeast Pacific Ocean, three partially sympatric populations of resident killer whales occupy coastal ecosystems from California to Alaska. One population (southern resident killer whales) is endangered, while another (southern Alaska resident killer whales) has exhibited positive abundance trends for the last several decades. Using 185 faecal samples collected from both populations between 2011 and 2021, we compare variability in diet preference to provide insight into differences in foraging patterns that may be linked with the relative success and decline of these populations. We find broad similarities in the diet of the two populations, with differences arising from spatiotemporal and social variability in resource use patterns, especially in the timing of shifts between target prey species. The results described here highlight the importance of comprehensive longitudinal monitoring of foraging ecology to inform management strategies for endangered, highly social top marine predators., Competing Interests: We declare we have no competing interests., (© 2024 The Authors.)

Understanding how the environment mediates an organism's ability to meet basic survival requirements is a fundamental goal of ecology. Vessel noise is a global threat to marine ecosystems and is increasing in intensity and spatiotemporal extent due to growth in shipping coupled with physical changes to ocean soundscapes from ocean warming and acidification. Odontocetes rely on biosonar to forage, yet determining the consequences of vessel noise on foraging has been limited by the challenges of observing underwater foraging outcomes and measuring noise levels received by individuals. To address these challenges, we leveraged a unique acoustic and movement dataset from 25 animal-borne biologging tags temporarily attached to individuals from two populations of fish-eating killer whales (Orcinus orca) in highly transited coastal waters to (1) test for the effects of vessel noise on foraging behaviors-searching (slow-click echolocation), pursuit (buzzes), and capture and (2) investigate the mechanism of interference. For every 1 dB increase in maximum noise level, there was a 4% increase in the odds of searching for prey by both sexes, a 58% decrease in the odds of pursuit by females and a 12.5% decrease in the odds of prey capture by both sexes. Moreover, all but one deep (≥75 m) foraging attempt with noise ≥110 dB re 1 μPa (15-45 kHz band; n = 6 dives by n = 4 whales) resulted in failed prey capture. These responses are consistent with an auditory masking mechanism. Our findings demonstrate the effects of vessel noise across multiple phases of odontocete foraging, underscoring the importance of managing anthropogenic inputs into soundscapes to achieve conservation objectives for acoustically sensitive species. While the timescales for recovering depleted prey species may span decades, these findings suggest that complementary actions to reduce ocean noise in the short term offer a critical pathway for recovering odontocete foraging opportunities., (© 2024 His Majesty the King in Right of Canada and The Author(s). Global Change Biology published by John Wiley & Sons Ltd. Reproduced with the permission of the Minister of Fisheries and Oceans Canada. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

"Why Sharks Matter: A Deep Dive with the World's Most Misunderstood Predator" by David Shiffman is a book that aims to dispel myths and misconceptions about sharks. The author, a marine conservationist, argues that healthy shark populations are beneficial for humans and that fear of sharks has led to the marginalization of shark conservation efforts. The book provides an overview of shark ecology and explores the challenges and controversies surrounding shark conservation. It also includes personal anecdotes, humor, and references to popular culture. The book concludes with information on shark organizations and ways for readers to get involved in shark conservation. [Extracted from the article]

"The Killer Whale Journals: Our Love and Fear of Orcas" by Hanne Strager is a captivating book that takes readers on a journey studying killer whales. The book combines elements of history, natural history, autobiography, and travel writing, providing a unique perspective on the relationships between humans and killer whales. While it may not be a traditional natural history book, it offers detailed descriptions of killer whale behaviors and explores various human-whale relationships around the world. The book is a fast-paced and enjoyable read, suitable for those interested in travel writing, research history, and encounters with the natural world. [Extracted from the article]

In odontocetes, synchronous visible displays accompany a small proportion of vocalizations but the function of these multimodal signals is still unclear.  Bouts of stereotyped pulsed calls were collected from two adult female killer whales (Orcinus orca) concurrently with behavioral observations and the incidence of two synchronous behaviors, bubble streams and nodding, were measured.  Thirty-four hours of focal individual data were collected in the presence of dependent calves in 1993 and 1994.  Overall, 471 pulsed calls were attributed to the two subjects using synchronous behaviors or independent cues (proximity, localization by ear in air).  Both subjects used the same stereotyped pulsed call repertoire and they ordered calls within bouts similarly, despite dissimilar previous histories.  Both nodding and bubble streams were disproportionately associated with a subset of stereotyped pulsed calls, but the subset was different for the two behaviors.  General Linear Model analysis was used to predict the relative odds that the subjects would be swimming with calves given call class and attribution cue.  Bubbling was not associated with significant odds that a subject would be swimming with one or more calves, but nodding was associated with significantly higher odds and resting calls with lower odds.  Given these observations, synchronous behaviors in the presence of calves could function in one or more of the following ways: altering the signal value of calls, emphasizing an aspect of the social context, and facilitating learning.  All are possibilities at the interface between cognition and communication that would have interested Stan Kuczaj.

The article reports that the fecal samples from cetaceans have been collected using scat-detecting dogs. Topics include examines the field operations were undertaken with a several meter rigid-hulled Zodiac with a custom-made bow pulpit, providing an elevated platform for the sampler; and considered the behaviors are typical for pilot whales during midday in Hawaiian waters.

The article offers information on Humpback whales that are well known to form closed rings of bubbles to encircle and concentrate prey for more efficient feeding—both alone and in cooperative groups. Topics include examines fin whales are typically considered a pelagic species, although they sporadically occur in shallow coastal waters of the Celtic Sea during autumn and winter to feed on shoals of spawning herring and sprat.

The sub-population of humpback whales inhabiting the Arabian Sea is a small and genetically distinct population that remains in low latitudes year-round. Designated as Endangered on the IUCN Red list of Threatened Species, the sub-population faces a number of threats throughout its range, including entanglement in fishing gear, ship strikes, disease and habitat degradation. Research conducted primarily off the coast of Sultanate of Oman over the past 20 years has contributed to understanding the population's distribution, abundance, and conservation status. However, information on the population's health and specific threats is limited. This study examines all available images of Arabian Sea humpback whales obtained between 2000 and 2018 for evidence of disease, predation, epizoites, ectoparasites, and human-induced scars and wounds. Tattoo skin disease-like lesions were detected in 41% of 93 whales, with a roughly equal distribution between males and females. Prevalence of the disease was significantly higher in 2012-2018 (51.7%) than in 2000-2011 (27.6%). Killer whale tooth rakes were detected on the ventral surface of the tail flukes of 12% (95% CI 4.5-18%) of 77 individuals. Roughly two thirds (66.6%: 95% CI 52-80%) of the 42 individuals represented by good quality photographs of the caudal peduncle region at the fluke insertion bore scarring patterns consistent with entanglement in fishing gear. At least two individuals showed severe injuries or deformations likely caused by interactions with fishing gear. Six individuals had injuries consistent with vessel strikes. Documented entanglement events from Oman and Pakistan involved large-mesh nylon gillnets, known to be used extensively throughout the Arabian Sea. These findings indicate an urgent need to design effective measures for the management and mitigation of threats, and to continue monitoring Arabian Sea humpback whales, with an emphasis on methods that allow continued and expanded assessment of health, body condition, and anthropogenic interactions. [ABSTRACT FROM AUTHOR]

The history of bowhead whaling and hunt management in the eastern and central Canadian Arctic is reviewed. Subsistence hunting of bowhead whales by Inuit resumed in the 1990s under co-management arrangements that were part of land-claims settlement agreements. Removals by whaling in both Canada and Greenland have been accounted for in IWC Scientific Committee assessments of the Eastern Canada-West Greenland (EC-WG) stock, but Canada, having withdrawn from IWC membership in 1982, has no legal obligation to consider IWC management advice. From 1994-2021 the total reported catch of bowheads in the central and eastern Canadian Arctic was 39 (not including struck-and-lost whales or whales that died from entanglement in fishing gear). Sixteen different communities, most of which had a long history of bowhead whaling prior to the arrival of commercial whalers, took at least one bowhead over that 27-year period. More than half of the recent catches have been by the communities of Igloolik, Sanijarak, Naujaat and Coral Harbour, all in the Foxe Basin-Repulse Bay-northern Hudson Bay region where at least occasional hunting of bowheads by local people had persisted until well into the 1970s. Greenland's reported landed catches totaled 8 from 2009-2015, with no successful hunts reported since 2015. Well over a third of the whales landed by both countries combined have been mature females, the most valuable class in terms of potential for population increase. Several factors in addition to hunting and entanglement in fishing gear are likely affecting EC-WG bowheads, including increased exposure to killer whale predation (linked to the massive reduction in sea ice) and other changes in ecological conditions driven primarily by climate change (e.g. more industrial activity, more vessel traffic, more noise). Recent analyses suggest the ECWG stock of bowheads has grown considerably since the end of commercial whaling, with best estimates of current abundance in the range of 6,000-7,000 individuals. Even though the population appears capable of sustaining present levels of removal and disturbance, it is important for monitoring efforts to continue in both Canada and Greenland, with regular Indigenous participation. [ABSTRACT FROM AUTHOR]

Fishery observer records from 2001 through 2016 were examined to document interactions, injuries, and mortalities of killer whales (Orcinus orca) associated with fishing operations in Alaska. Although widespread throughout Alaska, the highest numbers of such events occurred in the southeastern Bering Sea. Killer whales of the resident ecotype feeding on catch or discarded catch and fishermen using whale deterrence measures represented 96% (number of interactions [n]=3110) of all interactions examined in this study (n=3245). We found that 87% (n=2817) of all interactions occurred during longline operations. Both minor and serious injuries were documented. Twenty-seven killer whales were reported dead, but additional mortalities are assumed. Most whales killed were residents; however, 3 transient whales were also taken. Because killer whale populations are relatively small, a low level of mortality may significantly affect populations, especially if multiple sympatric stocks are shown to exist. Given the long history (i.e., over 6 decades) that Alaska killer whales have had with fishing operations, it is likely that these interactions will continue. [ABSTRACT FROM AUTHOR]