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Photography and video footage, captured by researchers and tourists on board two vessels, provided insights into the predation techniques employed by an adult male killer whale Orcinus orca in Mossel Bay, South Africa. The incapacitation of its prey, a juvenile white shark Carcharodon carcharias (∼2.5 m TL), followed by consumption of the liver, occurred within less than 2 minutes, highlighting the predator proficiency of the killer whale. Notably, another adult male killer whale, and constant traveling companion with the first, was observed approximately 100 m away and was not involved during the predation. The following day a second carcass of a different eviscerated white shark (3.55 m TL) washed ashore in the vicinity, indicating that at least two white sharks may have been killed during the interaction. [ABSTRACT FROM AUTHOR]

The Cold Pool is a subsurface layer with water temperatures below 2 °C that is formed in the eastern Bering Sea. This oceanographic feature of relatively cooler bottom temperature impacts zooplankton and forage fish dynamics, driving different energetic pathways dependent upon Bering Sea climatic regime. Odontocetes echolocate to find prey, so tracking foraging vocalizations acoustically provides information to understand the implications of climate change on Cold Pool variability influencing regional food web processes. Vocal foraging dynamics of ice-associated and seasonally migrant marine mammal species suggest that sperm whales spend more time searching for prey in warm years when the Cold Pool is reduced but are more successful at capturing prey during cold years when the Cold Pool is stronger. Beluga whale foraging vocal activity was relatively consistent across climate regimes but peaked during the warm regime. Killer whale foraging vocal activity peaked in both warm and cold regimes with indicators of different ecotypes exploiting changing prey conditions across climate regimes. Foraging activity of odontocete apex predators may serve as a sentinel indicator of future ecosystem change related to prey availability that is linked to a diminishing Cold Pool as water temperatures rise and seasonal sea ice decreases due to climate change. [ABSTRACT FROM AUTHOR]

The changes in the stable isotope ratios of carbon (δ13C), nitrogen (δ15N), oxygen (δ18O), and mercury (Hg) concentrations in muscle and liver tissues during and after lactation were studied in killer whales stranded along the coast of Hokkaido, in the northern area of Japan (n = 16). Calf muscles displayed δ13C- and δ15N-enriched peaks and a δ18O-depleted peak during lactation. The δ13C- and δ15N-enriched peaks appear to reflect the extensive nursing of 13C- and 15N-enriched milk and the onset of weaning, whereas the δ18O-depleted peak may be attributable to the extensive nursing of 18O-depleted milk and the onset of weaning. The δ13C and δ15N values tended to gradually increase after the weaning, whereas the δ18O values tended to decrease. The δ13C and δ15N levels in calves were similar between liver and muscle samples, whereas those in mature animals were higher in liver than in muscle samples. The isotopic turnover rates of C and N may be similar between the liver and muscle tissues in calves, which are rapidly growing animals. The Hg concentrations in muscle tissues were slightly higher in small calves than in large calves, probably due to the Hg transfer across placenta. The Hg concentrations in liver and muscle samples increased with increasing body length, and those in two liver samples from mature animals exceeded the high-risk threshold for marine mammal health effects (82 μg/wet g). [ABSTRACT FROM AUTHOR]

Endangered Southern Resident killer whales (Orcinus orca) are fish‐eaters that preferentially prey on adult Chinook salmon (Oncorhynchus tshawytscha). Despite being salmon specialists, individuals from all three killer whale pods (J, K, L) have been observed harassing and killing porpoises (family Phocoenidae) without consuming them. Retrospectively, we identified and analyzed 78 episodes of Southern Resident killer whales harassing porpoises between 1962 and 2020, of which 28 resulted in the porpoise's death ("phocoenacide"). Fifty‐six episodes involved harbor porpoise (Phocoena phocoena), 13 involved Dall's porpoise (Phocoenoides dalli), and the porpoise species was unreported for nine episodes. Southern Resident killer whales often targeted young porpoises that were similar in size to adult Chinook salmon. Both sexes participated in porpoise harassment. Juveniles engaged in the behavior the most; however, their rates of engagement were not found to differ significantly from most other age classes. The behavior was passed through generations and social groupings, as it was first observed in L pod and spread to the other two pods. Killer whales are highly complex animals known to exhibit social learning and cultural transmission of learned behaviors, but the reason(s) for this behavior is unknown. Hypotheses include the social and developmental benefits of play, hunting practice, or displaced epimeletic behavior. [ABSTRACT FROM AUTHOR]

Beginning in December 2018, increased numbers of gray whale (Eschrichtius robustus) strandings were reported along the west coast of Mexico, the United States, and Canada, prompting declaration of a gray whale Unusual Mortality Event (UME) by the United States National Marine Fisheries Service. Although strandings declined in 2020 and 2021 from a peak in 2019, the UME is still ongoing as of fall 2023. Between 17 December 2018 and 31 December 2021, 503 animals stranded along the west coast of North America, with 226 strandings in Mexico, 71 in California, 12 in Oregon, 56 in Washington, 21 in British Columbia, and 117 in Alaska. These included 187 males, 167 females, and 149 whales of undetermined sex; and 193 adults, 194 subadults, 40 calves, 1 fetus, and 75 whales of undetermined age class. We report on 61 of the 503 carcasses (12%) that had external and internal gross necropsy and/or histopathology data: of these 61 whales, findings that contributed to death were identified in 33 (54%) whales. Sixteen of the 61 (26%) were severely emaciated. Gross lesions of blunt force trauma consistent with vessel strike were identified in 11 of the 61 animals (18%), only two of which were emaciated. Two whales (3%) were entangled at time of death, and one died from entrapment. Signs of killer whale (Orcinus orca) interaction were documented in 19 of the 61 animals; five were deemed from recent interactions and three (5%) likely contributed to mortality. A specific cause of death could not be identified in 28 of 61 whales (46%). Additionally, logistical challenges and the advanced state of decomposition of most examined carcasses precluded detection of potential infectious or toxic causes of morbidity or mortality. Up to 2016, the eastern North Pacific population of gray whale population had generally been increasing since the cessation of historic whaling and a prior UME in 1999–2000. However, recent abundance and calf production estimates have declined, a trend that overlaps the current UME. The relative contributions of carrying capacity, environmental change, prey shifts, and infectious, toxic, and other processes to the increased gray whale mortalities have not yet been resolved. Nevertheless, the marked temporal increase in strandings, including findings of malnutrition in some of the whales, along with low calf production, likely represent consequences of complex and dynamic ecological interactions in the ocean impacting the population. [ABSTRACT FROM AUTHOR]

Here we update U.S. West Coast Biologically Important Areas (BIAs) that were published in 2015 using new data and approaches. Additionally, BIAs were delineated for two species that were not delineated in the 2015 BIAs: fin whales and Southern Resident killer whales (SRKW). While harbor porpoise BIAs remained the same, substantial changes were made for other species including identifying both larger overall areas (parent BIAs) and smaller core areas (child BIAs). For blue, fin, and humpback whales we identified, delineated, and scored BIAs using the overlap between the distribution and relative density from three data sources, leveraging the strengths and weaknesses of these approaches: 1) habitat density models based on Southwest Fisheries Science Center (SWFSC) line-transect data from systematic ship surveys conducted through 2018, 2) satellite tag data from deployments conducted by three research groups, and 3) sightings of feeding behavior from non-systematic effort mostly associated with small-boat surveys for photo-identification conducted by Cascadia Research Collective. While the previous BIAs were based solely on a more subjective assignment from only the small boat sightings, here we incorporate the other two data sources and use a more rigorous, quantitative approach to identify higher density areas and integrate the data types. This resulted in larger, better-supported, objective BIAs compared to the previous effort. Our methods are also more consistent with the delineation of BIAs in other regions. For SRKWs, the parent BIA was based on a modification of the Critical Habitat boundaries defined by the National Oceanographic and Atmospheric Administration (NOAA) and the Department of Fisheries and Oceans (DFO) Canada; a core BIA highlighting areas of intensified use was identified using both NOAA's Critical Habitat and kernel density analyses of satellite tag data. Gray whale BIAs were re-evaluated for the migratory corridor of Eastern North Pacific gray whales, for Pacific Coast Feeding Group feeding areas, and for gray whales that feed regularly in Puget Sound. [ABSTRACT FROM AUTHOR]

Transient killer whales have been documented hunting marine mammals across a variety of habitats. However, relatively little has been reported about their predatory behaviours near deep submarine canyons and oceanic environments. We used a long-term database of sightings and encounters with these predators in and around the Monterey Submarine Canyon, California to describe foraging behaviour, diet, seasonal occurrence, and habitat use patterns. Transient killer whales belonging to the outer coast subpopulation were observed within the study area 261 times from 2006–2021. Occurrences, behaviours, and group sizes all varied seasonally, with more encounters occurring in the spring as grey whales migrated northward from their breeding and calving lagoons in Mexico (March-May). Groups of killer whales foraged exclusively in open water, with individuals within the groups following the contours of the submarine canyon as they searched for prey. Focal follows revealed that killer whales spent 51% of their time searching for prey (26% of their time along the shelf-break and upper slope of the canyon, and 25% in open water). The remainder of their time was spent pursuing prey (10%), feeding (23%), travelling (9%), socializing (6%), and resting (1%). Prey species during 87 observed predation events included California sea lions, grey whale calves, northern elephant seals, minke whales, common dolphins, Pacific white-sided dolphins, Dall's porpoise, harbour porpoise, harbour seals, and sea birds. The calculated kill rates (based on 270 hours of observing 50 predation events) were 0.26 California sea lions per killer whale over 24 hours, 0.11 grey whale calves, and 0.15 for all remaining prey species combined. These behavioural observations provide insights into predator-prey interactions among apex predators over submarine canyons and deep pelagic environments. [ABSTRACT FROM AUTHOR]

Simple Summary: "How do animals perceive the world, and what are they thinking about?" To approach these questions, a method where animals face a touch screen and work on various visual tasks was used. There have not been many studies conducted on cetaceans (e.g., dolphins and whales) because the presence of water makes it difficult to use the electronic devices needed to study them. In this study, we aimed to train one captive killer whale to perform visual tasks using a monitor through an underwater window as if a touch panel were used. We started the training using real objects, which were then converted to photographs. Finally, we confirmed that the killer whale became able to perform the task even in monitor presentation. The successful use of this method suggests the possibility of conducting more detailed research on killer whale cognitive abilities, and further comparisons between terrestrial animals could be conducted in the future. This method is also expected to contribute to animal welfare, and it could also be used to propose new exhibitions to introduce the cognitive abilities of animals in zoos and aquariums. Matching-to-sample tasks have been a useful method in visual cognitive studies on non-human animals. The use of touch panels in matching-to-sample tasks has contributed to cognitive studies on terrestrial animals; however, there has been a difficulty in using these devices underwater, which is one of the factors that has slowed the progress of visual studies on underwater animals. Cetaceans (e.g., dolphins and whales) are highly adapted to underwater environments, and further studies on their cognitive abilities are needed to advance our understanding of the interactions between environmental factors and the evolution of cognitive abilities. In this study, we aimed to develop a new experimental method in which a captive killer whale performed a matching-to-sample task using a monitor shown through an underwater window as if a touch panel were used. In order to confirm the usefulness of this method, one simple experiment on mirror image discrimination was conducted, and the pairs with mirror images were shown to be more difficult to identify than the pairs with other normal images. The advantages of using this method include (1) simplicity in the devices and stimuli used in the experiments, (2) appropriate and rigorous experimental control, (3) the possibility of increasing the number of individuals to be tested and interspecies comparisons, and (4) contributions to animal welfare. The use of this method solves some of the problems in previous visual cognitive studies on cetaceans, and it suggests the further possibility of future comparative cognitive studies. It is also expected to contribute to animal welfare in terms of cognitive enrichment, and it could help with the proposal of new exhibition methods in zoos and aquariums. [ABSTRACT FROM AUTHOR]

The article discusses a study on the evidence for an oceanic population of killer whales (Orcinus orca) in offshore waters of California and Oregon conducted by Josh D. McInnes et al., published in the journal ". The study attempts to determine the ecotype of killer whales observed far from the coastlines based on their foraging behaviors, prey species consumed, morphologies, and the prevalence of cookiecutter shark bite scars.

Top marine predators, such as odontocetes, pinnipeds, and seabirds, are known to forage around fishing boats as fishermen aggregate and/or discard their prey. Recently, incidents of humpback whales interacting with fishing boats have been reported. However, whether humpback whales utilise discard fish as a food source and how they forage around fishing boats is unknown. This study reports, for the first time, the foraging behaviour of a humpback whale around fishing boats. Three whales were tagged using a suction‐cup tag containing a video camera, and a behavioural data logger in the coastal area of Tromsø, Norway. Video data from one tagged whale showed that the whale remained in close vicinity of fishing boats for 43 min, and revealed the presence of large numbers of dead fish, fish‐eating killer whales, fishing boats, and fishing gear. In waters with large numbers of dead fish, the whale raised its upper jaw, a motion associated with engulfing discard fish from fishing boats, and this feeding behaviour differed markedly from lunge‐feeding observed in two other whales in the same area. This behaviour was defined as "pick‐up feeding". No lunge feeding was seen on the data logger when the whale foraged around fishing boats. This study highlights a novel humpback whale foraging strategy: low energy gain from scattered prey but also low energy costs as high‐energy lunge feeding is not required. [ABSTRACT FROM AUTHOR]

In this paper, we have estimated the neutrino mass ordering and the CP violation sensitivity of the proposed Protvino to ORCA (P2O) experiment after 6 years of data-taking. Both unitary and non-unitary 3 × 3 neutrino mass mixing have been considered in the simulations. A forecast analysis deriving possible future constraints on non-unitary parameters at P2O have been performed. [ABSTRACT FROM AUTHOR]

Effective conservation of threatened populations requires identification of the processes limiting recovery. When multiple population processes are potentially limiting, they are sometimes analyzed independently, often using different datasets. Analytically, this is suboptimal, as processes are often correlated, which can lead to biased estimates of parameters and quantities of interest. Integrated population models (IPMs) can synthesize several data streams in the same probabilistic framework to circumvent these issues. Lack of prey was identified as one of the primary threats to recovery of critically endangered southern resident killer whales (SRKWs), Orcinus orca. Previous studies have correlated SRKW demographic rates with indices of Chinook salmon Oncorhynchus tshawytscha abundance, but these approaches have modeled reproduction and survival independently. We developed an IPM for SRKWs that models both processes simultaneously, as a function of Chinook salmon abundance along the west coast of North America. We used this model to evaluate the relationship between Chinook salmon abundance and demographic rates of SRKWs, with the goal of updating our understanding of a potential causal relationship between prey availability and SRKW population dynamics, and how these relationships may have changed over time. Results suggest that SRKW mortality rates are more strongly associated with Chinook salmon abundance than birth rates. Our analysis also suggests northern resident killer whale abundance could also be affecting SRKW carrying capacity, possibly through competition over shared prey resources. The IPM fit observed total abundance data well and predicted temporal changes in population demographics with reasonable accuracy, but small sample size may have opacified model selection. Our approach offers a valuable tool for predicting the response of the SRKW population to alternative management strategies involving the recovery of Chinook salmon stocks in the eastern Pacific. [ABSTRACT FROM AUTHOR]

Killer whales are an important sentinel species and developing non-invasive methods of health assessments might provide insight for understanding how wildlife health is influenced by ecosystem change. Rectal temperature (RT) is a proxy for core body temperature in managed-care cetaceans, however, this measurement is impractical for free-ranging cetaceans and infrared imaging has been suggested as an alternative. The aim of the current study was to prospectively compare infrared thermography of the blowhole to rectal temperatures in killer whales, as well as establish a healthy range for rectal temperature using retrospective data. Infrared video was recorded from the blowhole of thirteen healthy killer whales in managed care, immediately followed by rectal temperature measurement. Repeated measures Bland-Altman analysis revealed blowhole temperature (BHT) had a bias of -1.28°C from RT. Considerable proportional bias was observed with agreement between measurements improving as mean temperature increased. RT positively associated with air temperature, and inversely associated with body mass. BHT was not significantly affected by sex or body mass but was significantly affected by water temperature and air temperature. Retrospective analysis from eighteen killer whales (n = 3591 observations) was performed to generate expected RT ranges, partitioning out for sex and body mass. Given the proportional bias observed with Bland Altman analysis, BHT cannot currently be recommended as a measurement for absolute core body temperature, however infrared thermography of the blowhole remains a promising tool for health assessment of free-ranging killer whale populations, as it may serve as a non-contact screening tool to detect pyrexic animals within a group.

Abstract Effective conservation of threatened populations requires identification of the processes limiting recovery. When multiple population processes are potentially limiting, they are sometimes analyzed independently, often using different datasets. Analytically, this is suboptimal, as processes are often correlated, which can lead to biased estimates of parameters and quantities of interest. Integrated population models (IPMs) can synthesize several data streams in the same probabilistic framework to circumvent these issues. Lack of prey was identified as one of the primary threats to recovery of critically endangered southern resident killer whales (SRKWs), Orcinus orca. Previous studies have correlated SRKW demographic rates with indices of Chinook salmon Oncorhynchus tshawytscha abundance, but these approaches have modeled reproduction and survival independently. We developed an IPM for SRKWs that models both processes simultaneously, as a function of Chinook salmon abundance along the west coast of North America. We used this model to evaluate the relationship between Chinook salmon abundance and demographic rates of SRKWs, with the goal of updating our understanding of a potential causal relationship between prey availability and SRKW population dynamics, and how these relationships may have changed over time. Results suggest that SRKW mortality rates are more strongly associated with Chinook salmon abundance than birth rates. Our analysis also suggests northern resident killer whale abundance could also be affecting SRKW carrying capacity, possibly through competition over shared prey resources. The IPM fit observed total abundance data well and predicted temporal changes in population demographics with reasonable accuracy, but small sample size may have opacified model selection. Our approach offers a valuable tool for predicting the response of the SRKW population to alternative management strategies involving the recovery of Chinook salmon stocks in the eastern Pacific.

The Northern California Current is a highly productive marine upwelling ecosystem that is economically and ecologically important. It is home to both commercially harvested species and those that are federally listed under the U.S. Endangered Species Act. Recently, there has been a global shift from single-species fisheries management to ecosystem-based fisheries management, which acknowledges that more complex dynamics can reverberate through a food web. Here, we have integrated new research into an end-to-end ecosystem model (i.e., physics to fisheries) using data from long-term ocean surveys, phytoplankton satellite imagery paired with a vertically generalized production model, a recently assembled diet database, fishery catch information, species distribution models, and existing literature. This spatially-explicit model includes 90 living and detrital functional groups ranging from phytoplankton, krill, and forage fish to salmon, seabirds, and marine mammals, and nine fisheries that occur off the coast of Washington, Oregon, and Northern California. This model was updated from previous regional models to account for more recent changes in the Northern California Current (e.g., increases in market squid and some gelatinous zooplankton such as pyrosomes and salps), to expand the previous domain to increase the spatial resolution, to include data from previously unincorporated surveys, and to add improved characterization of endangered species, such as Chinook salmon (Oncorhynchus tshawytscha) and southern resident killer whales (Orcinus orca). Our model is mass-balanced, ecologically plausible, without extinctions, and stable over 150-year simulations. Ammonium and nitrate availability, total primary production rates, and model-derived phytoplankton time series are within realistic ranges. As we move towards holistic ecosystem-based fisheries management, we must continue to openly and collaboratively integrate our disparate datasets and collective knowledge to solve the intricate problems we face. As a tool for future research, we provide the data and code to use our ecosystem model. [ABSTRACT FROM AUTHOR]

The article informs about the identification of the ecotype origin of an entangled killer whale using remnant mtDNA after being found dead and ensnared in recreational Dungeness crab gear off the coast of Newport, Oregon. Topic include the study uses investigative molecular methods to determine the killer whale's ecotype, highlighting the significance of genetic markers in identifying sympatric groups within killer whale populations in the Northeast Pacific.

Toothed cetaceans represent a diverse and important component in poorly studied pelagic food webs. We used the variation in δ13C and δ15N values in tooth dentin and bone collagen sampled from 185 specimens of 23 species (families Delphinidae, Physeteridae, Kogiidae, Phocoenidae, and Ziphiidae) stranded in the western South Atlantic Ocean (WSAO) to estimate the isotopic niche width and assess the interspecific isotopic niche overlap. Two gradients of increasing δ13C values among species were evidenced: ocean-coast and high-to-low latitudes. Variation in δ13C and δ15N values indicated the existence of at least four trophic and habitat-related guilds: neritic high trophic-level predators (Pseudorca crassidens, Tursiops truncatus gephyreus, T. truncatus truncatus and Phocoena spinnipinis); oceanic intermediate trophic-level predators (Orcinus orca, Steno bredanensis, Kogia breviceps, Lagenodelphis hosei, Physeter macrocephalus, Delphinus delphis and Stenella frontalis), oceanic low trophic-level predators (Grampus griseus, P. crassidens—mass stranded group, Mesoplodon grayi, M. densirostris, Ziphius cavirostris, Globicephala melas, S. coeruleoalba, and K. sima), all from the subtropics, and a temperate/polar grouping of neritic/oceanic low trophic-level predators (Berardius arnuxii, M. layardii, M. hectori and P. dioptrica). Furthermore, our results also suggest the occurrence of putative ecotypes of O. orca and P. crassidens. The isotopic niche width was highly variable among species, with high niche overlap among several oceanic taxa. The results of the present study suggest a wide variation in trophic position, habitat and, therefore, the ecological role of different odontocete species in the WSAO ecosystems. [ABSTRACT FROM AUTHOR]

Investigating the movements and site fidelity of individuals enhances our understanding of population ecology and structure. Killer whales occur around the coast of Iceland; however, information on the connectivity between different regions is limited to herring grounds, where they are observed frequently. In this study, we used photo-identification data to investigate the movements and site fidelity of whales within (South and West) and outside (Southwest, Northwest, Northeast and East) Icelandic herring grounds. Additionally, we used a 10-year photo-identification dataset in the South to investigate long-term site fidelity patterns to a single location. Of the 440 individuals sighted more than once, nearly half (48%) moved between herring grounds and site fidelity was higher within, compared to outside, herring grounds. Outside herring grounds, individuals showed: more movement from Southwest to West compare to South, indicating this region is not exclusively a passage between herring grounds; low site fidelity to the Northeast with fewer photographic matches to other regions, suggesting individuals found here may be part of an offshore population that occasionally visits the area; and low proportion of matches to other regions in the Northwest and East, although small sample sizes precluded firm conclusions. Finally, long-term residency of killer whales in the South showed dynamic patterns, likely caused by prey availability and/or environmental changes. This study elucidates the complexities of killer whale occurrence and connectivity within the North Atlantic and suggests population structure that should be further investigated for appropriate regional conservation assessments. [ABSTRACT FROM AUTHOR]

Nonselective beta‐blockers (NSBBs) may exacerbate ascites by impairing cardiac function. This study evaluated the impact of achieving a heart rate target of 55–60 beats per minute (bpm) on ascites‐related death and complications from worsening ascites in patients with cirrhosis and diuretic‐responsive ascites using NSBBs. A retrospective study was conducted at the Faculty of Medicine Ramathibodi Hospital, Mahidol University (2012–2022) and analyzed patients with cirrhosis and diuretic‐responsive ascites using NSBBs (propranolol/carvedilol) for variceal bleeding prophylaxis. The outcomes were incidence of ascites‐related death and complications from worsening ascites, comparing the achievable target group (heart rate 55–60 bpm) and the unachievable target group (heart rate >60 bpm). A total of 206 patients were included in the study, with a median follow‐up time of 20 months. The patients were divided into an achievable target group (n = 75, median heart rate = 58.0 bpm) and an unachievable target group (n = 131, median heart rate = 73.6 bpm). Propranolol was the most used NSBB (95.1%). The adjusted hazard ratio (HR) for ascites‐related death from spontaneous bacterial peritonitis (SBP) or refractory ascites (RA) or hepatorenal syndrome (HRS) or hepatic encephalopathy (HE) showed no difference between the groups (adjusted HR 0.59 [0.23–1.54]; p = 0.28). Additionally, no significant difference was found in the incidence of complications between groups, including SBP, RA, HRS, and HE. Achieving a heart rate target of 55–60 bpm with NSBBs for variceal bleeding prophylaxis is safe in patients with diuretic‐responsive ascites and cirrhosis. [ABSTRACT FROM AUTHOR]

This article discusses the use of acoustic tags and bottom-moored recorders to study the impulsive sounds produced by humpback whales during surface active behavior. The study combines data from passive acoustic monitoring (PAM) and instrumented suction cup tags to gain insights into humpback whale behavior and communication. The impulsive sounds were found to be associated with surface-active behaviors such as tail slaps and pectoral fin slaps. The presence of these impulsive sounds in PAM data can provide valuable information about the occurrence and activity of humpback whales in a monitored area. [Extracted from the article]

This document provides a compilation of scientific articles that explore various aspects of killer whale behavior, ecology, and interactions with other marine species. The articles discuss the use of drones to study killer whales, their feeding habits and prey selection, their distribution and abundance, and their role in marine ecosystems. The document emphasizes the importance of using drone footage and citizen science to gain insights into killer whale behavior and conservation efforts. The articles cover a range of regions around the world, providing valuable information on killer whales in different contexts. [Extracted from the article]

Information on marine mammals and marine birds in US Pacific Northwest waters is limited but necessary to assess potential impacts from proposed and planned human activity (for example, cable installation, energy and port development) as required by regulatory permitting processes, particularly relative to recent plans for offshore wind development. We conducted daily opportunistic, non-systematic observations of marine mammals and marine birds in autumn 2014 and of marine mammals in summer 2015 to meet mitigation and monitoring requirements associated with a geophysical site characterization survey for a proposed offshore wind floating platform demonstration project off Coos Bay, Oregon. Two biologists completed observations during daylight with the naked eye and reticle binoculars from a 17-m vessel between Coos Bay and the proposed platform site 30 km offshore. In 2014, 1058 h (3244 km) of observation occurred during 3 October through 4 November, with 1182 h (4367 km) observations conducted from 10 July through 28 August 2015. In total, 543 groups (approximately 1389 individuals) representing at least 14 marine mammal species and 7444 groups (approximately 18322 individuals) representing at least 22 marine bird species were observed. Sighting rates (number of individuals observed per 100 km of observation) were higher for nearly every species of marine mammal in summer 2015 than autumn 2014. An extralimital sighting of 25 Bottlenose Dolphins (Tursiops truncatus) and 5 sightings of rare transient Killer Whales (Orcinus orca) were documented. Results address a gap in site-specific marine mammal and marine bird baseline occurrence data and information required to assess effects of proposed offshore wind development and other human-related activities near Coos Bay, Oregon, as well as climate and oceanographic changes. [ABSTRACT FROM AUTHOR]

Cooperative hunting between humans and killer whales (Orcinus orca) targeting baleen whales was reported in Eden, New South Wales, Australia, for almost a century. By 1928, whaling operations had ceased, and local killer whale sightings became scarce. A killer whale from the group, known as "Old Tom," washed up dead in 1930 and his skeleton was preserved. How these killer whales from Eden relate to other populations globally and whether their genetic descendants persist today remains unknown. We extracted and sequenced DNA from Old Tom using ancient DNA techniques. Genomic sequences were then compared with a global dataset of mitochondrial and nuclear genomes. Old Tom shared a most recent common ancestor with killer whales from Australasia, the North Atlantic, and the North Pacific, having the highest genetic similarity with contemporary New Zealand killer whales. However, much of the variation found in Old Tom's genome was not shared with these widespread populations, suggesting ancestral rather than ongoing gene flow. Our genetic comparisons also failed to find any clear descendants of Tom, raising the possibility of local extinction of this group. We integrated Traditional Custodian knowledge to recapture the events in Eden and recognize that Indigenous Australians initiated the relationship with the killer whales before European colonization and the advent of commercial whaling locally. This study rectifies discrepancies in local records and provides new insight into the origins of the killer whales in Eden and the history of Australasian killer whales. [ABSTRACT FROM AUTHOR]

A psychophysical procedure was used to measure pure-tone detection thresholds for a killer whale (Orcinus orca) as a function of both signal frequency and signal duration. Frequencies ranged between 1 and 100 kHz and signal durations ranged from 50 μs to 2 s, depending on the frequency. Detection thresholds decreased with an increase in signal duration up to a critical duration, which represents the auditory integration time. Integration times ranged from 4 ms at 100 kHz and increased up to 241 ms at 1 kHz. The killer whale data are similar to other odontocete species that have participated in similar experiments. The results have implications for noise impact predictions for signals with durations less than the auditory integration time. [ABSTRACT FROM AUTHOR]

A systematic analysis of the species composition of the prey of killer whale Orcinus orca Linnaeus, 1758 was carried out. The results of observations of killer whales hunting for different types of prey and the data from an analysis of the contents of their stomachs were summarized; the species affiliation of the prey was compared with the affiliation of predators to the R- or T-type based on a genetic analysis. It has been shown that killer whales of the Far Eastern seas of Russia have a pronounced foraging specialization, which correlates with the haplotype of the mitochondrial DNA control region. Killer whales with the NT1 and GAT haplotypes previously described for mammal-eating T-type killer whales from the northeast Pacific (also called Bigg's killer whales) have been observed preying on marine mammals but not on fish. Killer whales with the SR haplotype, previously described for fish-eating R-type killer whales from the northeastern Pacific, preyed only on fish. Two new T-type killer whale haplotypes have been discovered; animals with these haplotypes have been observed preying on large baleen whales. The importance of traditions and social learning in the differentiation of ecological niches in cetaceans has been noted. The specialization to hunt certain prey transmitted from mother to calves allows killer whales of different ecotypes to avoid food competition and acquire morphological and behavioral adaptations that facilitate hunting for a particular type of prey. [ABSTRACT FROM AUTHOR]

Introduction: Killer whales (Orcinus orca) have a global distribution, but many low-latitude populations such as the Eastern Tropical Pacific are not well studied. Objective: Provide a review of killer whale sightings in the Exclusive Economic Zone of the Pacific of Guatemala, for which there has previously been little information. Methods: We reviewed national and regional publications, as well as anecdotal records of killer whale sightings in Guatemala. Results: We document five sightings spanning three decades (1990-2020). Four sightings were recorded between 2010 and 2020 and occurred within the San José Canyon or over the continental shelf. Group size varied from 1-15 individuals (: 6 ± 4.3). We report a photographic match of three killer whale individuals from a single pod previously sighted in Cabo Corrientes, México, 11 years and 1 778 km apart. We also describe an interaction between a killer whale pod and two adult Bryde's whales (Balaenoptera edeni), in which the Bryde's whales followed a female killer whale and its calf. Conclusions: This study represents a contribution to the knowledge of killer whales in the region. It highlights the importance of data collection from both scientific and anecdotal records and supports the need of establishing national and regional monitoring and conservation programs for cetaceans. [ABSTRACT FROM AUTHOR]

Introduction: Worldwide, false killer whales (Pseudorca crassidens) are infrequently encountered, yet long-term studies have shown strong site fidelity as well as long-term associations among individuals in several locations. Detailed studies of this species have primarily been conducted around tropical oceanic islands or in the subtropical southern hemisphere. Objectives: We assess movements and association patterns among false killer whales along the Pacific coasts of the USA, Mexico, Guatemala, Nicaragua, Costa Rica including Isla del Coco, and Panama, representing one of the longest-running (albeit non-continuous) studies of this species. We also examine photos for evidence of interactions with fisheries, a known source of mortality to false killer whales. Methods: From Central America, we selected 212 individuals (50 encounter groups) out of 244 individuals (56 encounters) for inclusion in analyses based on photo quality and distinctiveness. Photos were collected on dedicated surveys from 1991-1994 and dedicated and opportunistic surveys from 1998-2022. Other than the effort off the oceanic Isla del Coco (1993-1994), surveys were undertaken in continental shelf waters. Additionally, we selected by photo quality and distinctiveness 124 (33 encounter groups) out of 189 individuals from southern California and Mexico for inclusion in these analyses. Association patterns were analyzed in SOCPROG and movements were analyzed in R. Results: Of the 328 total individuals, 158 (48.2 %) were encountered more than once, and 114 (34.8 %) were re-sighted after a year or more. The longest individual sighting history spanned 26.2 years with six re-sightings over that period between southern Costa Rica and Panama. Association and movement analyses revealed that individuals identified off southern Costa Rica and Panama linked into a single social network, with extensive movements between the two countries. Three individuals encountered off northern Costa Rica were re-sighted off northern Nicaragua, and individuals encountered off Nicaragua were encountered off Guatemala and central mainland Mexico. Nine matches were found among false killer whales between central mainland Mexico and Central America. There were no matches between the mainland coastal waters and the 33 individuals encountered around Isla del Coco. Dorsal fin disfigurements consistent with interactions with line fisheries ranged from 0 to 21 % for individuals within social clusters identified by community division. Conclusions: The infrequency of sightings combined with a high re-sighting rate of individuals and groups from the same area, suggests multiple small populations with large home ranges that include coastal waters. Small populations are sensitive to environmental changes, and as the human population grows, so do the demands on fisheries and ecotourism, which could directly impact the different populations. Additional effort in offshore areas is needed to determine the population status of false killer whales in pelagic waters, how often false killer whales using coastal waters move into pelagic waters, and the relationship between whales in the two habitats. [ABSTRACT FROM AUTHOR]

Over the last decade, the second-order N-electron valence state perturbation theory (NEVPT2) has developed into a widely used multireference perturbation method. To apply NEVPT2 to systems with large active spaces, the computational bottleneck is the construction of the fourth-order reduced density matrix. Both its generation and storage become quickly problematic beyond the usual maximum active space of about 15 active orbitals. To reduce the computational cost of handling fourth-order density matrices, the cumulant approximation (CU) has been proposed in several studies. A more conventional strategy to address the higher-order density matrices is the pre-screening approximation (PS), which is the default one in the ORCA program package since 2010. In the present work, the performance of the CU, PS, and extended PS (EPS) approximations for the fourth-order density matrices is compared. Following a pedagogical introduction to NEVPT2, contraction schemes, as well as the approximations to density matrices, and the intruder state problem are discussed. The CU approximation, while potentially leading to large computational savings, virtually always leads to intruder states. With the PS approximation, the computational savings are more modest. However, in conjunction with conservative cutoffs, it produces stable results. The EPS approximation to the fourth-order density matrices can reproduce very accurate NEVPT2 results without any intruder states. However, its computational cost is not much lower than that of the canonical algorithm. Moreover, we found that a good indicator of intrude states problems in any approximation to high order density matrices is the eigenspectra of the Koopmans matrices. [ABSTRACT FROM AUTHOR]

Killer whales (Orcinus orca) are experiencing increasing environmental pressures, with some ecotypes being identified as endangered, and the development and validation of non-invasive health assessment tools is critical for assessing the well-being of individuals within these endangered populations. Infrared thermography of the blowhole is a non-contact method of temperature measurement that was recently investigated in killer whales in managed care. Two male killer whales presenting with clinical signs at separate institutions had veterinary clinical health assessments performed, which included infrared thermography of the blowhole as well as concurrent rectal temperature measurement. The current case report is aimed at describing the clinical use of infrared thermography of the blowhole as a method to detect elevated body temperature in two killer whales. Both animals exhibited blowhole temperatures above the previously reported values (36.4 °C and 37.6 °C; the mean in healthy whales is reported to be 34.21 ± 1.47 °C) with concurrently elevated rectal temperatures, as well as clinicopathologic findings consistent with a systemic inflammatory response (e.g., neutrophilia, increased fibrinogen and erythrocyte sedimentation rate, hypoferritinemia). Following veterinary intervention, both animals’ blowhole and rectal temperatures returned to baseline. Infrared thermography of the blowhole represents a promising tool for the identification of pyrexic animals and with further investigation may be considered as part of conservation health assessments for threatened free-ranging populations.

In this contribution to the special software-centered issue, the ORCA program package is described. We start with a short historical perspective of how the project began and go on to discuss its current feature set. ORCA has grown into a rather comprehensive general-purpose package for theoretical research in all areas of chemistry and many neighboring disciplines such as materials sciences and biochemistry. ORCA features density functional theory, a range of wavefunction based correlation methods, semi-empirical methods, and even force-field methods. A range of solvation and embedding models is featured as well as a complete intrinsic to ORCA quantum mechanics/molecular mechanics engine. A specialty of ORCA always has been a focus on transition metals and spectroscopy as well as a focus on applicability of the implemented methods to "real-life" chemical applications involving systems with a few hundred atoms. In addition to being efficient, user friendly, and, to the largest extent possible, platform independent, ORCA features a number of methods that are either unique to ORCA or have been first implemented in the course of the ORCA development. Next to a range of spectroscopic and magnetic properties, the linear- or low-order single- and multi-reference local correlation methods based on pair natural orbitals (domain based local pair natural orbital methods) should be mentioned here. Consequently, ORCA is a widely used program in various areas of chemistry and spectroscopy with a current user base of over 22 000 registered users in academic research and in industry. [ABSTRACT FROM AUTHOR]

Depredation (wild predators feeding on fish caught by man) is a global concern in the fishing industry. Solutions to this type of conflict necessarily involve setting up an observation program to understand and quantify the phenomenon. This study takes the example of the toothfish (Dissostichus eleginoides) fishery around the Kerguelen and Crozet archipelagos in the southern Indian Ocean. Collaboration between the various stakeholders involved like the management authority (TAF or Terres australes françaises), the scientists (MNHN, CNRS, IRD) and the fishermen was the key to the rapid implementation of data collection from the late 90s onwards. The fishery observers employed by TAF cover 100% of the fishing effort on board the eight authorized vessels. The experience gained has been presented and benefited to other observer programs.

Conservation management planning for highly mobile species requires an understanding of the distribution of areas that are biologically important to the species of concern. Collecting data on the locations of animal behaviors linked to biological characteristics, such as foraging, can be used to spatially describe biological important areas. However, spatial modeling of free-ranging animal behavior can be challenging, as behavioral observations of animals are often clustered, and sampling is commonly conducted at a higher frequency than changes in behavioral states, resulting in data that are usually highly autocorrelated in space and time. Here, we fit latent Gaussian process models to observational behavioral data to generate spatially-explicit predictions of foraging behavior within the critical habitat of an endangered population of fish-eating killer whales (Orcinus orca) in southern British Columbia, Canada, and northern Washington State, USA. We compare spatial models treating temporal autocorrelation in behavior in three ways: (1) ignoring temporal autocorrelation entirely; (2) traditional data-thinning to remove temporal autocorrelation, and; (3) using a temporal Gaussian process to account for temporal autocorrelation. Comparisons of autocorrelative structures for each model and visual comparison of broad spatial patterns demonstrate that our third approach yields more accurate results than when ignoring temporal autocorrelation entirely and higher precision results than when applying data-thinning methods. Within the identified areas of critical habitat, our models indicate two primary regions of intense killer whale foraging activity, and we delineate areas wherein the probability of foraging was particularly high as candidate locations for conservation management actions. This study underscores the value of refining our understanding of high-use areas for at-risk species by incorporating animal behavior data to inform area-based conservation measures.

The conservation of wildlife is one of the most pressing issues in the current times, but wildlife conservation economic values have often been largely ignored due to an absence of market prices, as setting an economic value on biodiversity or whole ecosystems can be challenging. Nevertheless, valuing wildlife can be of great significance to improve decision-making in the conservation field, as it can provide a complementary perspective based on economic principles. Whale-watching provides an opportunity for the economic valuation of wildlife. Specifically, it offers a framework in which the economic revenue allows the economic valuation of the targeted cetaceans to be estimated through the direct and indirect expenditure of the tourists who purchase whale-watching tours. Here, we performed an economic analysis based on population abundances of the three main species targeted by the whale-watching companies in the Strait of Gibraltar (Spain): long-finned pilot whales (Globicephala melas), common dolphins (Delphinus delphis) and killer whales (Orcinus orca). These species generated a total annual income of €4,089,056, €1,876,833, and €505,389, respectively, and each individual would generate an average of €14,048, €951, and €36,099 each year, respectively. Incorporating life expectancy, this corresponded to a total population value of €112,426,185, €16,685,147, and €19,171,107, respectively, over their lifetime. These values provide an idea of the potential contribution of cetaceans to the local economy but only represent their non-consumptive value based on tourism. Our results reinforce the idea that a sustainable, high-quality whale-watching culture, under ACCOBAMS High-Quality Whale-Watching requirements, should be promoted to ensure a sustainable industry, stable economic income and the viability of cetacean populations in the Strait of Gibraltar.

Collective decision‐making is an essential part of day‐to‐day life for group‐living animals. These decisions can be unshared (e.g. leadership) or shared (e.g. consensus).Aquatic mammals face particular challenges when making collective decisions, including a three‐dimensional habitat that can make group coordination and collective navigation a challenge.We systematically reviewed literature on decision‐making in non‐human mammals by examining the types of collective decisions observed and hypotheses used to structure analyses.Most of the current literature was centred around terrestrial species, particularly within primates and artiodactyls. There are no collective decision‐making studies on aquatic mammal species outside of cetaceans. Both unshared and shared decision‐making have been reported in whales and dolphins, with leadership found in killer whales Orcinus orca and bottlenose dolphins Tursiops sp. and consensus decisions in sperm whales Physeter macrocephalus.Five recommendations for decision‐making research include: 1) clearly delineating the temporal components of decision‐making, 2) standardising research to allow for comparisons, 3) considering both shared and unshared decision‐making, 4) analysing decision‐making across behavioural contexts, and 5) avoiding anthropomorphic terminology.Future studies of collective decision‐making will help us better understand how non‐human mammals overcome environmental and contextual challenges – particularly in the case of aquatic species such as cetaceans, which face challenges related to their aquatic environment and exhibit phenomena such as mass strandings. [ABSTRACT FROM AUTHOR]

This document is a compilation of various research papers and reports related to cetacean research and management. It covers a wide range of topics including abundance estimates, aerial surveys, subsistence whaling, conservation efforts, pollution and climate change impacts, marine ecosystem monitoring, population status, acoustic monitoring, genetics, photo-identification, foraging grounds, whale watching, migratory patterns, ship-strikes, collision risk, entanglement response, deep seabed mining, and population regulation. The papers and reports provide valuable information for researchers and conservationists interested in studying and protecting cetaceans in different regions of the world. [Extracted from the article]

During glacial periods, highly mobile species were able to shift their ranges to warmer regions that remained ice-free--so-called "glacial refugia." Glacial refugia often preserved higher levels of genetic diversity than areas that were colonized after the retreat of glaciers. In this study, we examined genetic and vocal variation in R-type ("resident") killer whales, Orcinus orca, from Nemuro Strait in the western North Pacific to test the hypothesis that environmentally stable marine regions may have preserved refugial populations of the killer whale that retained historical genetic and cultural diversity. We found three distinct mtDNA control region haplotypes and stereotyped calls that differed significantly from the repertoire of a population further north off Kamchatka and the adjacent western North Pacific. Therefore, both genetic and cultural evidence suggest that at least some killer whales from Nemuro Strait represent a separate maternal lineage. The control region haplotype diversity for Nemuro Strait is comparable to that for the rest of the North Pacific. The data presented here are consistent with the existence of the southwestern glacial refugium for killer whales in the waters off northern Japan during the Last Glacial Maximum. [ABSTRACT FROM AUTHOR]

Killer whales (Orcinus orca) have group-specific call repertoires that can be used to track groups and populations using passive acoustic monitoring. To provide a detailed description of the Icelandic killer whale repertoire and its variation, we analyzed acoustic data collected in five locations between 1985 and 2016. Calls were classified manually, and CART and random forest analyses were employed to validate the manual classification. A total of 91 call categories (including call types and subtypes) were defined. Most call categories were recorded in more than one location, with the highest proportion shared between herring grounds in Vestmannaeyjar (South) and Breiðafjörður (West). However, both locations included call categories that were not recorded elsewhere in Iceland. Recordings from past herring wintering grounds in eastern Iceland included few call categories that matched other locations. Sample sizes from Reykjanes (Southwest) and Skjálfandi (North) were small and did not include unique call categories. The relative occurrence of call categories in Vestmannaeyjar changed little over a 14-year period (2002-2016), although shorter-term changes between years were observed that appeared to correlate to changes in individuals identified. This comparison of acoustic repertoires provides valuable information on the social structure and movement patterns of herring-eating killer whales around Iceland. [ABSTRACT FROM AUTHOR]

Killer whales (Orcinus orca) are highly mobile, large marine apex predators that inhabit all oceans. Despite being the most conspicuous top predator, little is known about their ecology along Patagonia, Argentina. Here, we used carbon (d13C) and nitrogen (d15N) isotope analysis of bone and dentine collagen from killer whales (n = 13) stranded in northern Patagonia during the period 1970-2014 to assess their trophic ecology. A model-based clustering analysis identified three distinct groups related with three large marine ecosystems: the Patagonia (P), Subtropical (ST), and Antarctica (A) groups. Group P (n = 8) is characterized by individuals with high d13C and d15N values fitting within the isotopic ratios observed over the Patagonian shelf. Group ST (n = 3) is composed of individuals with high d13C and low d15N values, similar to those reported for conspecifics in southern Brazil. Group A (n = 2) is composed of individuals with low d13C and d15N values, typical from high latitude areas like sub-Antarctic/Antarctic waters. The finding of different killer whales' isotopic groups over the Patagonian shelf suggests the existence of individuals or groups exploiting different habitats. Our results expand the limited ecological knowledge for the species while presenting the basis to infer more complex ecological hypotheses. [ABSTRACT FROM AUTHOR]

Empirical assessment of cetacean welfare to inform stranding interventions is lacking. Here, potential welfare indicators are described for two stranded pygmy killer whales (Feresa attenuata), along with euthanasia procedures and pathology of potential relevance. The animals were filmed for 3.5 and 1.5 hr, respectively, allowing assessment of 19 indicators, including animal behaviors and human interventions. Eight interventions and 19 animal behaviors were identified; 17 and 11 behaviors were displayed by animal 1 and 2, respectively. Examination of ballistics euthanasia revealed atypical projectile placement and characterized animal behavioral responses, but welfare implications could not be assessed as insensibility was not verified in-field. Pulmonary edema and renal degeneration were documented in both animals; differential etiologies include ischemia-reperfusion, shock, and/or myopathy. Potential relationships among histopathology and welfare indicators are explored to infer affective experiences. For example, simultaneous head-lifting with respiration increased over time which, alongside pulmonary edema, suggests these animals experienced breathlessness. Other likely affective states include fatigue and discomfort; there are insufficient data to estimate the intensity or duration of these experiences or to provide an overall welfare grade/score. Further data are required to validate the proposed welfare indicators and to progress development of holistic approaches to welfare assessment at cetacean strandings. [ABSTRACT FROM AUTHOR]

The accuracy of quantum mechanics (QM) simulations depends heavily on the quality of initial input files. Despite the popularity of QM simulation packages, achieving precise results still heavily relies on the user's proficiency in preparing the QM simulation systems. In this work, we present an easy‐to‐use tool called GUIDE, a YASARA plugin to assist researchers in quantum chemistry workflow automation using ORCA and MOPAC simulation packages. GUIDE lets users compute complex QM calculation workflows via an automated graphical window system. It allows for a more integrated and streamlined research process, as researchers can easily access all the necessary tools within one software without switching between multiple programs. This tool can save time and increase efficiency in computational chemistry methods. GUIDE is written in Python and is freely available for download at https://github.com/YAMACS-SML/GUIDE. The plugin is released under a GPL‐3.0 license and is supported on Windows and Linux. [ABSTRACT FROM AUTHOR]

Early detection and classification of breast cancer can be facilitated to initiate the most effective treatment. As the second leading cause of death among women, early breast cancer screening is essential for reducing mortality rates. In this context, Convolutional neural networks (CNNs) are the ideal candidate for increasing the rate of identification and classification of tumours with efficiency, particularly in medical imaging. This research proposes a hybridised CNN with the Orca Predation Optimization Algorithm (OPOA) as a novel classification model for the effective detection of abnormalities in breast cancer diagnosis. Specifically, the OPOA technique is used to determine the optimal hyperparameter values for the hybrid CNN architecture being deployed. As the pretrained CNN model, the suggested model utilizeds a ResNet50 residual network. It merged OPOA with the ResNet50 residual network to construct the OPOA-ResNet-50 Architecture. The experimental validation of the proposed OPOA-ResNet-50 model utilising the datasets of curated breast imaging subset of DDSM (CBIS-DDSM) shown improved classification accuracy of 99.04%, specificity of 98.56%, and sensitivity of 97.78% in comparison to the baseline techniques. The results also revealed that the proposed under mammographic image analysis society (MIAS) OPOA-ResNet-50 model demonstrated superior classification accuracy of 98.64%, specificity of 98.79%, and sensitivity of 98.82% compared to the benchmarked methods. The adopted OPOA algorithm is determined to achieve more optimal hyperparameter values for the ResNet50 architecture than the comparative algorithms Improved Marine Predator Optimization Algorithm (IMPOA), Whale Optimization Algorithm (WOA), Harris hawk's optimization (HHO), and gravitational search algorithm (GSA). [ABSTRACT FROM AUTHOR]