Search

This article discusses an observation of killer whales harassing humpback whales in offshore Brazilian waters. The observation took place in August 2023 and involved killer whales chasing and surrounding the humpback whales, with instances of physical contact. The behavior suggests that the killer whales may be targeting the humpback whales as prey. While fatal attacks are rare, there have been reports of such attacks in different regions of the world. The article also mentions that killer whales generally target smaller or younger whales during attacks. The observations provide new insights into the interactions between killer whales and humpback whales in the region, but it is unclear if these interactions have increased or are being recorded more frequently due to improved technology. This collection of scientific articles explores various aspects of killer whale interactions with other marine species in different regions, providing valuable insights into their behavior and ecological implications. These findings contribute to our understanding of the complex relationships between marine species and can inform conservation efforts. [Extracted from the article]

This article discusses observations of killer whale attacks on sei and fin whales in the Magellanic Sub-Antarctic Waters of Chile. The attacks occurred between March 2020 and April 2021 and resulted in the death of the whales. The researchers were able to identify one female killer whale involved in three of the attacks, which is relatively rare. The study emphasizes the need for further research on the trophic ecology and dietary plasticity of killer whales in the area. Additionally, a collection of articles and studies on killer whale behavior, diet, and interactions with other marine species is provided. [Extracted from the article]

Although killer whale (Orcinus orca) predation on humpback whales (Megaptera novaeangliae) is rarely witnessed, resultant scars on humpback flukes provide evidence of non-lethal interactions. Humpback whale photo-identification catalogs from the North Atlantic were used to evaluate humpback flukes (n = 10,957) for the presence and severity of killer whale scarification (e.g., rake marks, teeth indentations, missing tissue). Flukes were coded as none, light, moderate, or severe based on the extent of scarring. Even with increased sample sizes, especially for Norway and Iceland, the distribution of high-latitude humpbacks with killer whale scarring was consistent with prior studies: Atlantic Canada (21.7%), West Greenland (15.5%), Gulf of Maine (13.5%), Iceland (combined with East Greenland, 9.3%), and Norway (7.9%). For the first time, scarring rates are presented based on data from Ireland, Scotland, and England (11.0%) as well. Scarring frequencies generally differed between the eastern and western North Atlantic despite the co-occurrence of all migrating humpbacks in low-latitude breeding grounds, suggesting the occurrence of killer whale interactions in the distinct feeding grounds or along northward migration routes. While it was not possible to determine exactly where these interactions took place, the likelihood of a killer whale encounter and subsequent scar acquisition was greatest for humpbacks that feed in Atlantic Canada. [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.

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.

The article presents the discussion on Killer whales (Orcinus orca), being the top predators in marine ecosystems. Topics include little direct evidence of sea otter consumption by killer whales, with only one consumption among the attacks; and predation was not considered to play a role in the decline.

Historically, there has been only one documented fatal killer whale (Orcinus orca) attack on a fin whale (Balaenoptera physalus)--from Baja California, Mexico (BC), in 2005. We compiled records of seven more recent fatal attacks, including four more from BC. Two male killer whales that we identified were involved, separately or together, in at least four of the five fin whale kills off BC as they traveled with their groups the length of the Baja Peninsula on both sides. They were also involved in two Bryde's whale (Balaenoptera edeni) kills, and we suggest that they might specialize on large whale prey. We discuss offensive and defensive strategies during these attacks and the role (or lack thereof) of adult male killer whales. One of the fin whales taken appeared to be a healthy adult, which raises questions about large whales as prey for killer whales. We also discuss the burgeoning role of citizen science in this type of research, noting that most of our data came from social media postings. [ABSTRACT FROM AUTHOR]

The killer whale (Orcinus orca) is a cosmopolitan cetacean distributed worldwide. Extensive studies have described its ecology and behavior across multiple polar and temperate regions. On the other hand, there is limited information on the distribution, ecological roles, and abundance of killer whales in tropical and subtropical regions. Herein, we build on previous work to update information on the spa-tiotemporal distribution, exploitation, and natural history of killer whales in the Caribbean Sea. We also document new records on their interaction with other species and human activities. We collated 385 records from the literature, online biodiversity information systems, the Internet (social networks and video-hosting websites), and citizen science-based initiatives. Records included sightings (87.3%), intentional captures (10.6%), bycatch (0.3%), and strandings (1.8%). Data primarily originated from research projects/activities (57%) and citizen science-based initiatives (43%). Records were distributed in the eastern Caribbean (39.5%), the southern Caribbean (19.7%), the Greater Antilles (19.2%), the Bahamian Region (13.0%), Central America (6.8%), and eastern Florida (1.8%). Killer whales were recorded year-round, but most data were reported between March and August (59.6%). The scarcity of records in Central America could reflect true lower densities in the region, lower observation effort, or a combination of the two. Because of the paucity of data, this study supports the growing importance of citizen-science initiatives to document the occurrence and ecology of this species in the Caribbean. Our dataset also confirms the occasional and widespread occurrence of killer whales throughout the Caribbean Sea. Potential low densities and limited predictability of their occurrence hinder dedicated research on this species. [ABSTRACT FROM AUTHOR]

The article reports that orcas or killer whales are among the most cosmopolitan cetaceans on the planet. Topics include considered in the semi-enclosed sea of the Gulf of California in México, sightings of orcas are considered relatively frequent year-round; and examines little is known about their ecology and hunting behavior in this region.

The article reports that the marine mammals developed various feeding strategies, including cooperative foraging in groups. Topics include medians the cooperative feeding is more common in social marine mammals like odontocetes that include smaller oceanic dolphins and killer whales as the cooperative feeding allows these species to hunt more efficiently by working together to gain access to food.

The article reports that same-sex behavior has been documented in a wide range of animal taxa and is a common feature of social species. Topics include examines the functional and evolutionary significance of same-sex behavior in animals is uncertain as samesex behavior can be used to promote social bonds between same-sex individuals, to maintain dominant/subordinate relationships without aggression or to promote reconciliation after it.

The article focuses on mammalian integument coloration that mainly depends on the amount and type of melanin which is regulated by the enzyme tyrosinase. Topics include examines the dark coloration of cetaceans is mainly a result of the presence of melanocytes and considered melanocytes produce melanin, which is stored in the dorsal part of the skin of cetaceans, while white body parts do not contain melanin due to anomalies in the tyrosinase.

The article reports that various species of cetaceans annually visit the Pacific coast of Colombia. Topics include considered while others are present throughout the year as humpback whales belongs to breeding stock G (BSG), recognized by the International Whaling Commission are commonly seen in the Gulf of Tribugá on an annual basis.

The article reports that the Humpback whales are a cosmopolitan species that often visit inshore waters close to the coast, making it easier to see and study them. Topics include considered assessing whale behavior offers a better understanding of the importance of these species in marine ecosystems as well as give knowledge about their ecology and habitat use.

The article describe one of the most dramatic behavioral responses individuals have witnessed in several playback trials with natural and anthropogenic sounds to dozens of marine mammal species. Topics include examines three stimuli were presented several min apart and observers on the RHIB were blind to the playback sequence and identity of the calls used in each trial.

The article focuses on Gray whales that are the only extant species of Eschrichtiidae. Topics include examines in the North Pacific, they comprise a western population of several animals and an eastern group with several individuals as of 2021/2022 and considered these animals have the longest migration route of any marine mammals, which extends from summer feeding grounds in the Bering, Chukchi and Beaufort Seas to calving, breeding and assemblage areas off Baja California and Mexico.

The article describes an interaction between two cetacean species such as the sperm whale and the short-finned pilot whale. Topics include examines the event occurred on June 6, 2021 during a research survey and considered the crew of Pelagic Life, AC and the Marine Mammal Laboratory at Universidad Veracruzana was surveying the Continental Slope off the Veracruz coast in the southwestern Gulf of Mexico when a mother–calf sperm whale pair was observed.

The article reports that passive acoustic monitoring and multisensory tagging methods have increased the number of studies focused on the nocturnal behavior of whales. Topics include examines the humpback whales known as Megaptera novaeangliae migrate long distances between feeding and breeding grounds.

Killer whales (Orcinus orca) are marine apex predators distributed across the world's oceans. In the last 40 years, researchers have increasingly differentiated killer whales into ecotypes based on genetics, morphology, behaviour, acoustic repertoire, habitat, and trophic ecology. While killer whale ecotypes in the Northern Hemisphere are well studied, the recognition of distinct killer whale forms in the Southern Hemisphere is mainly limited to Antarctic waters. Although present in less studied regions, such as along the Atacama Desert coast in the Southeast Pacific Ocean, limited information is available regarding their biology or trophic ecology. Herein, multiple lines of evidence are presented for killer whale predation on marine mammals in northern Chile. Using information from systematic boat-based surveys, whale-watching tour surveys, and reports from fishermen/citizen scientists, 19 killer whale sightings are reported along the coast of northern Chile (from the Arica and Parinacota region in the north to the Atacama region in the south). Killer whales were photo-identified as corresponding to the Southern Hemisphere Type A-like ecotype according to their dorsal fin shape and white eye patch. One killer whale pod, which included two males, one female, one juvenile, and one calf, was resighted six times from 2016 to 2021 in northern Chile and was observed hunting South American sea lions (Otaria flavescens), dusky dolphins (Lagenorhynchus obscurus), and long-beaked common dolphins (Delphinus cf. capensis). Killer whales were observed taking advantage of large aggregations of sea lions associated with the offshore purse-seine fishery. Adult killer whales used the hulls of fishing vessels to prevent sea lions from escaping. Photo-identification analysis of a fin whale (Balaenoptera physalus) catalogue from Mejillones Peninsula showed that 2.6% of all identified whales had apparent rake marks from killer whale teeth on their dorsal fins. These data show that Type A-like killer whales in northern Chile prey on several species of marine mammals. [ABSTRACT FROM AUTHOR]

The rapid emergence of new marine developments (e.g., marine renewables, port infrastructure) alongside the substantial growth of existing industries has ultimately resulted in an unprecedented increase in anthropogenic structures within the marine environment over the previous century. Knowledge of whether marine species interact with, avoid, or accommodate and adapt to such structures is essential to ensure that further development of marine environments do not compromise conservation objectives of marine species. This article documents one such interaction. Herein, we describe the observation of a harbour seal (Phoca vitulina) seeking refuge from a group of foraging killer whales (Orcinus orca) within a blue (aka common) mussel (Mytilus edulis) farm. Aerial video footage (38 min 27 s) was collected using an unmanned aerial system during an encounter at an aquaculture site in Dury Voe, Shetland, UK. Analysis of the footage showed the killer whale group spent 73.7% of the total encounter time exhibiting predatory associated behaviours and that they were observed interacting with the mussel farm infrastructure only during "predation activity" for a total of 26 min 52 s (72.8%). The harbour seal interacted with the mussel farm infrastructure during re- and proactive anti-predator behaviour and when exhibiting fatigue for 27 min 59 s, 94.4% of the total time the seal was observed. It is clear that both marine and terrestrial predator-prey interactions are increasingly occurring in settings that are in some way defined by the Anthropocene. The implications of this are discussed, including potential entanglement risk and human-altered "landscapes of fear." As comprehension of the potential effects of human-altered risk grows, such knowledge should be taken into consideration prior to further modification of marine habitats. [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.

The article discusser the case of a Humpback whale (Megaptera novaeangliae) from the West Indies. Topics include North Atlantic Humpback Whale Catalogue (NAHWC) has identified and catalogued individuals from all major areas of humpback aggregation; and whales migrating from the Dominican Republic have been found in the higher latitude feeding grounds of the Gulf of Maine, Newfoundland, and Labrador.

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.

Very little is known about the foraging ecology of killer whales (Orcinus orca) in tropical oceans and on how these large apex predators affect prey communities. In most tropical waters, the presence of killer whales is unpredictable, and most information on their ecology is inferred from opportunistic records. This is particularly the case in the Indian Ocean where limited information is available. Between 2002 and 2017, killer whales were opportunistically encountered around the Mozambique Channel island of Mayotte in the eastern Comoros Archipelago (southwest Indian Ocean). A total of 15 killer whale sightings collected by various local experts were compiled and used to describe observed feeding events. Twenty-seven distinct individuals from four separate groups were identified by photo-identification, highlighting short-term site fidelity (minimum 7 days) to this area. Feeding was observed on seven occasions, and recorded prey included two species of elasmobranchs (Centroscymnus coelolepi and Mobula spp.) and two species of cetaceans: a humpback whale (Megaptera novaeangliae) calf and a pantropical spotted dolphin (Stenella attenuata). This study represents the first account of killer whales foraging on a combination of marine mammals and elasmobranchs in tropical waters, and describes the first presumed predation on a humpback whale calf in the southwest Indian Ocean. [ABSTRACT FROM AUTHOR]

The article reports on the first sighting of pygmy killer whales (Feresa attenuata) in Cuba. Also cited are the similarities of the whales to the melon-headed whale (Peponocephala electra) and false killer whale (Pseudorca crassidens), the differences in the behavior of Feresa attenuata and Peponocephala electra, and the stranding of two injured Feresa attenuata, which were treated with oxytetracycline and vitamin complex and released to the ocean.

The article discusses the recorded intentional stranding of mammal-hunting killer whales (Orcinus orca) in the Salish Sea. Also cited are the observed intentional stranding by the killer whales in Patagonia to feed on southern sea lions (Otaria flavescens) and southern elephant seals (Mirounga leonina), and the frequent sightings of the whales that visited the Salish Sea in the waters off Southern Vancouver Island, British Columbia, and Puget Sound, Washington.

Killer whales are known to live strand in many regions around the world. Some populations regularly and repeatedly do so in pursuit of prey, but this behaviour is otherwise relatively rare. Off the west coast of North America, historical records of live stranded killer whales indicate that most individuals perished, were euthanized, or captured for aquariums where they subsequently died. Few details are available on which of the three culturally distinct killer whale ecotypes in this region have been involved in live stranding events (LSEs) and on the survival of any individuals that were able to unstrand. In this article, we report details on four LSEs since 2002 and, together with previous records, show that all live-stranded killer whales documented in this region during the last four decades have been of the Bigg's ecotype. There was no predominant sex or age class involved in these events, but among the five individuals reported herein, all three adults stranded on sandy shores, whereas both juveniles stranded on rocky outcroppings while hunting harbour seals. Stranded individuals were kept cool and wet by human responders during three of the four LSEs, and efforts were twice made to move the animals off the shore. All individuals survived the LSEs, although one adult male was never seen again. The other four individuals rejoined their respective families soon after becoming unstranded and have been photo-identified with them on numerous occasions since. One adult female that was pregnant when stranded gave birth to a healthy calf several months later. These results indicate that (1) human responses to live-stranded killer whales are not always necessary, but when they are, they can help preserve their lives, family bonds, and culture and (2) LSEs are a natural risk associated with the foraging ecology of the Bigg's killer whale ecotype. [ABSTRACT FROM AUTHOR]

The article offers information on Humpback Whale (Megaptera novaeangliae) Resighted Eight Years After Stranding. It mentions Release attempts in places with wide tidal ranges must be made during the high tide to facilitate flotation and decrease negative impacts on the animal, skin must be intact over most of the body—smooth, shiny, and free of large wounds and without proliferation of epibionts.

The article offers information on Depredation by Killer Whales (Orcinus orca) on a Blue Shark (Prionace glauca) in Northeastern Atlantic. It mentions first report of shark depredation by killer whales in the North Atlantic, further studies are needed to determine if killer whales prey frequently on sharks in the North Atlantic Ocean.

In this article the author talks about the Humpback Whales which investigate the Carcass of a killer Whale-Depredated Gray Whale Calf. It mentions that Scientists have observed postmortem attentiveness to a deceased member of one's own species, or thanatology, in various animal taxa, including cacophonous aggregations in crows skull fondling by elephants and leaf-dropping/adornment by chimps.

We used photo-identification catalogs to assess the occurrence of rake marks in northern resident (NRKW) and transient (TKW) killer whale ecotypes from the northeastern Pacific. Rakemark coverage on visible surface areas, excluding dorsal fins, was grouped into four categories: (1) None (0%), (2) Mild (1 rake mark to < 25%), (3) Moderate (25 to 50%), and (4) Severe (> 50%). We conducted pairwise comparisons on density of rake marks with sex, age, and ecotype using mixed model, ordinal logistic regression. In NRKWs, rake marks increase with age in males (p = 0.0007), and males had a higher frequency and density than females (p < 0.0001) and juveniles (p = 0.02), with no difference between females and juveniles. Male residents > 30 years had an 8-fold higher frequency of severe rake marks than any younger 5-year age group (p < 0.0001), while no such relationship was seen in females (p = 0.30). In TKWs, rake marks also increase with age in males (p < 0.0001) and females (p < 0.0001), though no difference was found (p = 0.1) between males and females. NRKWs and TKWs had differences in rake-mark frequency and distribution (p = 0.004) due mostly to an increase in density (p = 0.003) in female transient vs female resident killer whales. While final confirmation will require behavioral observations, and based on our indirect results, we hypothesize that the increased aggression in older males from both ecotypes is due to sexual competition; and in transients, it is potentially due to prey competition. The increased aggression observed in transient adult females compared to resident females may be due to sexual coercion and/or an increased need to reestablish dominance in the more fluid social hierarchy, while increases observed for transient senescent females may be due to an increased need for calf protection. [ABSTRACT FROM AUTHOR]

The article reports an encounter with a North Pacific right whale in eastern Chukotka. It mentions that Pacific right whale was approached and photographs were taken of flukes and both sides of the animal's head for individual photo identification. It also mentions that abnormal travelling pattern could be related to the recent rapid increase in annual temperatures that has been reported to in annual temperatures that has been reported to and temperate marine species.

The article offers information on a male pygmy killer whale that was held in human care for 985 days after a successful stranding recovery. It mentions that researchers examined male's hematology and blood chemistry values to estimate potential ranges associated with good health. It also mentions that they also analysed seasonal change of serum testosterone and testes size for the purpose of future rescue and rehabilitation.

The article discusses the impact of killer whale predation on gray whale demographics that may be responsible for a large proportion of their natural mortality. Topics discussed include the projection of Bigg's killer whale sounds, gray whale calling during migration and foraging in the presence of vocalizing killer whales, acoustic silence by the gray whale, and nursing and weaning by gray whale cow-calf pairs.

The article offers information on the observation of killer whales in both hemispheres in the Eastern Tropical Pacific and mentions killer whales off Peru points to both oceanic and neritic distribution with predation observations targeting including Tursiops truncatus, Globicephala species, Arctocephalus australis, and Otaria flavescens. Topics discussed include a sighting of an adult male killer whale, photo-identification catalogs of killer whales, and resident fish eating.

The article presents the results of a study which analyzed bite marks and scars on western gray whales (Eschrichtius robustus) by killer whales (Orcinus orca). Topics of discussion include photoidentification of gray whales off Sakhalin Island, Russia, in the North Pacific Ocean, new scars by non-calf whales, and sex ratio among gray whales.

The article offers information on a study of cookiecutter shark bite wounds on cetaceans of the Gulf of Mexico (GOM). Several cetacean species with cookiecutter shark bite wounds were observed in GOM which include beaked whale, sperm whale (Physeter macrocephalus), and killer whale (Orcinus orca). Also provided are stable isotope ratios for sperm whales, cookiecutter sharks, and sperm whale preys.

This article summarizes our observations from land and vessels of transient (Bigg's) ecotype killer whales (Orcinus orca) in the Kuril Islands during the period 2002 to 2015. We also conducted a review of published information on the occurrence of these killer whales in the Kuril Islands. During 12 years of vessel observations, no cases of killer whales hunting marine mammals were observed. During land-based observations, Bigg's killer whales were observed from land near two Kuril Islands: Brat Chirpoev Island and Dolgaya Rock. In total, eight instances of Bigg's killer whale attacks on pinnipeds were observed: seven were directed toward Steller sea lions (Eumetopias jubatus) and one toward northern fur seals (Callorhinus ursinus). The behavior of killer whales during hunting corresponded to published descriptions of the tactics used by killer whales in other regions. According to the photo-identification analysis in July 2009 and July 2011, the same group of four Bigg's killer whales was observed near Brat Chirpoev Island. These individuals were not found in any of the published catalogues of killer whales inhabiting the North Pacific. According to both the information collected by us and that in published literature, the predominant ecotype of killer whales summering in the Kuril Islands is the fish-eating (resident) ecotype. [ABSTRACT FROM AUTHOR]

The article focuses on Killer whales in the coastal waters off Norway that are known to follow the seasonal movements of herring, a major prey item for the whales. Topics include examines photo identification studies of killer whales in Norwegian waters were initiated in the 1980s in areas where herring concentrated on wintering grounds and during spawning in the spring.

This article examines the prevalence of vertebral column deformities in Norwegian and Icelandic killer whales. It discusses the challenges in monitoring the health of free-ranging cetaceans, the basis for vertebral column deformities in cetacean species, the types of physical deformities identified, and complications resulting from the deformities.

Killer whales (Orcinus orca) are highly social top predators distributed throughout the world's oceans. They are divided into different ecotypes according to foraging specializations, phenotype, and social organization. For Northern Hemisphere killer whale ecotypes, acoustic behaviour has been shown to relate to foraging strategies and social organization. In contrast to the intensively studied Northern Hemisphere ecotypes, distribution patterns, social structures, and acoustic behaviour of the Southern Hemisphere killer whale ecotypes are poorly known. One of the Southern Hemisphere ecotypes, the Antarctic Ecotype C killer whale, is known to occur in regions with dense pack ice. The limited accessibility of these areas make passive acoustic monitoring (PAM) methods a very effective investigation tool to derive information on ecotype-specific abundance and distribution. During 2 d in February 2013, it was possible to collect concurrent visual and acoustic information of Ecotype C killer whales off the Antarctic continent. From these events, a call type catalogue was compiled. The 2,238 examined calls were subjectively classified into 26 discrete call types. Ten percent of the examined calls were re-classified by two additional independent observers to examine robustness of the classification. Mean classification accordance among observers was 68%. Most call types were composed of more than one call part. Sixty-five percent of all call types were monophonic, and 35% were biphonic. Almost two-third of all call types started with a short, broadband pulse. The variability within call types was relatively high. The Ecotype C vocal repertoire contained typical acoustic features such as biphonation, high call complexity, and generally high variability in frequency modulation. For future studies, the distinct characteristics of some of the call types described herein could potentially serve as acoustic markers for PAM-based differentiation of killer whale ecotypes in the Southern Ocean. [ABSTRACT FROM AUTHOR]

The article offers information on False killer whales occurring in the tropical and temperate waters of all oceans at latitudes lower than 50° with a core range from 40°N to 40°S. Topics include false killer whales from South America are from infrequent mass strandings Straits of Magellan, and the distribution and diversity of most pelagic marine organisms linking to sea surface temperature .

The article reports on the killer whale, known as Orcinus orca and its occurrence in the Moray Firth, Northeast Scotland. Topics discussed include the incidental sightings of this species, its behavioural observations, and photo-identification. Also being discussed are the white-beaked dolphins called Lagenorhynchus albirostris, and annual pupping season of the common seal called Phoca vitulina.

The article discusses the discovery of White Killer Whales in the Western North Pacific Region. It states that three different white killer whales were encountered around the Commander Islands, Russia from 2008 through 2015. It mentions that the White Killer Whales discovered belong to the resident or fish-eating ecotype.

An immature female killer whale (Orcinus orca) stranded in the Wadden Sea in 2010 and was later transferred to Loro Parque, Tenerife, Spain, for rehabilitation. The killer whale, named "Morgan," was suspected to have a hearing impairment. To test whether Morgan has a hearing deficit, auditory brainstem responses to short-duration, broadband click stimuli were recorded. The same procedure was conducted with five other killer whales at Loro Parque for comparative purposes. Stereotypical click-evoked responses were recorded in all of the killer whales except Morgan, even at the highest click level that could be projected. Reductions in the amplitude of the click-evoked response paralleled reductions in the stimulus amplitude of the clicks presented to all of the other whales. The lack of a click-evoked response in Morgan indicates that she suffers from a hearing deficit. The magnitude and frequency range over which the hearing deficit occurs cannot be specified with the techniques used here. Nevertheless, it can be concluded that Morgan's hearing sensitivity to broadband signals is at least 20 to 30 dB worse than the hearing sensitivity of the other killer whales tested. Morgan potentially suffers from a profound hearing deficit or even a complete loss of hearing, but this cannot be determined through the electrophysiological tests used in this experiment. [ABSTRACT FROM AUTHOR]

Behavioral observations can provide insight into the ecology and habitat use of marine species. Studies have shown that movement patterns are influenced by prey availability and that the presence of vessels can reduce foraging, resting, and/ or social behaviors in delphinids, including killer whales (Orcinus orca). Southern resident killer whales are listed as "Endangered" in both the United States and Canada. Reduced prey availability and vessel disturbance are risk factors for this population. Surface observations were conducted to understand southern resident killer whale behavior and habitat use in their Endangered Species Act-designated core summer critical habitat. The activity budget comprised 70.4% travel, 21.0% forage, 6.8% rest, and 1.8% social behavior. Dive duration, surface duration, and swim speed varied significantly among activity states and validated the activity state classifications. For example, traveling killer whales swam the fastest and had the lowest surface to dive duration ratios, which presumably minimizes energetic costs while maximizing distance traveled. Movement patterns, spatial arrangements, and configurations of killer whales also varied significantly among activity states and, to some extent, varied by geographic location. We found that killer whale spatial arrangement and configuration patterns were strikingly different in two adjacent areas, indicating that these may change abruptly. This may be informative for vessel operators who are required to maintain a 182.9-m distance from killer whales. Killer whales engaged in most activity states throughout the area, but foraging and resting predominantly occurred in some localized regions. Activity budgets reported in the present and other contemporary studies differ from those reported 20 to 30 y ago. The proportion of forage in the activity budget has decreased in recent years, yet the main foraging area has persisted for several decades. These findings are important for understanding key risk factors for southern resident killer whales and may aid in formulating mitigation measures to protect them from vessel traffic and other human activities. [ABSTRACT FROM AUTHOR]

In the early 1950s, probably 1955, a group of killer whales (Orcinus orca) became entrapped in developing landfast sea ice in northeast Foxe Basin in the eastern Canadian Arctic (Nunavut). Reports of killer whale ice entrapments are rare, and this is, to our knowledge, the only fatal entrapment reported for the Canadian Arctic. The entrapment was previously reported and briefly discussed by Blackadar (1964), but significant additional information became available from local Inuit elders, some of whom experienced the event first-hand. We summarize Inuit knowledge of this ice entrapment, using (1) semi-directed interviews with 12 hunters and elders conducted in 2008 and 2010 as part of a study on Inuit knowledge on Arctic killer whales, (2) a first-hand account of the event provided by a local elder in 2006 and 2011, and(3) transcripts from the Igloolik Oral History Database (extracted in 2008). Previous authors have noted that hunters harvested two killer whales, a female and a calf, but local knowledge summarized here indicates that more killer whales, at least five and probably 11 to 12, were entrapped and at least two harvested, while the rest likely died. Local knowledge also provided new information that the killer whales were entrapped in a different location than previously reported and that they survived in the breathing hole for several months before harvest. Inuit are reliable observers with excellent recall abilities, particularly for observations of rare events related to the natural environment that encompasses their way of life. The observations reported here are significant in understanding the physiology of killer whale starvation in cold waters, for managers monitoring frequency of episodic events, and in developing appropriate responses to rare entrapment events. [ABSTRACT FROM AUTHOR]