Journal articles: 'Killer whales (Orcinus orca)'

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Silber, Gregory K., Michael W. Newcomer, and Héctor Pérez-Cortés M. "Killer whales (Orcinus orca) attack and kill a Bryde's whale (Balaenoptera edeni)." Canadian Journal of Zoology 68, no. 7 (July 1, 1990): 1603–6. http://dx.doi.org/10.1139/z90-238.

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On 3 May 1988, we observed a group of killer whales that pursued, killed, and partially consumed a Bryde's whale in the northern Gulf of California, Mexico (31°01′N, 114°15′W). The attack was observed from 06:54 to 08:53 while circling in a single-engine aircraft at an altitude of 160 m. The group comprised about 15 killer whales, including two adult males and at least two calves. Females and (or) subadult males pressed the attack most intently. The killer whales tore skin and blubber from the right flank of the Bryde's whale, and on 11 occasions the killer whales swam onto the head or back of the Bryde's whale, which hindered its breathing. The respiration intervals of the Bryde's whale were short and irregular, and blow rates differed significantly from those of undisturbed Bryde's whales. Fatiguing the whale may have facilitated an easier kill by asphyxiation. After the death of the Bryde's whale, the two adult male killer whales surfaced slowly about 200–300 m away from the remainder of the group, which presumably fed on the submerged Bryde's whale carcass. Two days later, the drifting Bryde's whale carcass was located. A large wound was visible on the abdomen, and sections of the lower jaw had been removed. Like those of canids and some felids that hunt cooperatively when preying on ungulates, attacks by Orcinus orca exhibit coordination of activities and efficiency in dispatching prey.

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Dunn, Charlotte, and Diane Claridge. "Killer whale (Orcinus orca) occurrence and predation in the Bahamas." Journal of the Marine Biological Association of the United Kingdom 94, no. 6 (August 6, 2013): 1305–9. http://dx.doi.org/10.1017/s0025315413000908.

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Killer whales (Orcinus orca) have a cosmopolitan distribution, yet little is known about populations that inhabit tropical waters. We compiled 34 sightings of killer whales in the Bahamas, recorded from 1913 to 2011. Group sizes were generally small (mean = 4.2, range = 1–12, SD = 2.6). Thirteen sightings were documented with photographs and/or video of sufficient quality to allow individual photo-identification analysis. Of the 45 whales photographed, 14 unique individual killer whales were identified, eight of which were re-sighted between two and nine times. An adult female (Oo6) and a now-adult male (Oo4), were first seen together in 1995, and have been re-sighted together eight times over a 16-yr period. To date, killer whales in the Bahamas have only been observed preying on marine mammals, including Atlantic spotted dolphin (Stenella frontalis), Fraser's dolphin (Lagenodelphis hosei), pygmy sperm whale (Kogia breviceps) and dwarf sperm whale (Kogia sima), all of which are previously unrecorded prey species for Orcinus orca.

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Whitehead, Hal, and Randall Reeves. "Killer whales and whaling: the scavenging hypothesis." Biology Letters 1, no. 4 (July 26, 2005): 415–18. http://dx.doi.org/10.1098/rsbl.2005.0348.

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Killer whales ( Orcinus orca ) frequently scavenged from the carcasses produced by whalers. This practice became especially prominent with large-scale mechanical whaling in the twentieth century, which provided temporally and spatially clustered floating carcasses associated with loud acoustic signals. The carcasses were often of species of large whale preferred by killer whales but that normally sink beyond their diving range. In the middle years of the twentieth century floating whaled carcasses were much more abundant than those resulting from natural mortality of whales, and we propose that scavenging killer whales multiplied through diet shifts and reproduction. During the 1970s the numbers of available carcasses fell dramatically with the cessation of most whaling (in contrast to a reasonably stable abundance of living whales), and the scavenging killer whales needed an alternative source of nutrition. Diet shifts may have triggered declines in other prey species, potentially affecting ecosystems, as well as increasing direct predation on living whales.

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Hairr, John. "Killer Whales (Orcinus orca) Off the North Carolina Coast 1709–2011." Journal of North Carolina Academy of Science 128, no. 2 (July 1, 2012): 39–43. http://dx.doi.org/10.7572/2167-5880-128.2.39.

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Abstract Killer whales, Orcinus orca, were first reported off North Carolina by naturalist John Lawson in 1709, and during the 20th century were documented from North Carolina eight times in the scientific and popular literature. The most recent confirmed sighting of killer whales off North Carolina was in the spring of 2011. There have been no reports of killer whale deaths from North Carolina. There has been only one killer whale stranded along the North Carolina coast, with the animal being alive when it was returned to the sea. All sightings have been in the waters of the Atlantic Ocean, none on the west side of the Outer Banks in the waters of Pamlico or Currituck sounds. Only three confirmed reports are from nearshore waters, while the rest were spotted more than 20 km offshore. Orcas are most frequently reported from the waters off the Outer Banks from Cape Lookout north to the Virginia border. A 200 yr gap exists in the historical record of killer whales from North Carolina.

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Xu, Jinshan, Z. Daniel Deng, Thomas J. Carlson, and Brian Moore. "Target Strength of Southern Resident Killer Whales (Orcinus orca): Measurement and Modeling." Marine Technology Society Journal 46, no. 2 (March 1, 2012): 74–84. http://dx.doi.org/10.4031/mtsj.46.2.2.

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AbstractA major criterion for permitting the deployment of tidal turbines in Washington State’s Puget Sound is management of risk of injury to killer whales from collision with moving turbine blades. An active monitoring system is being proposed to detect and track killer whales within proximity of turbines and alert turbine operators of their presence and location to permit temporary turbine shutdown when the risk of collision is high. Knowledge of the target strength (TS) of killer whales is critical to the design and application of active acoustic monitoring systems. In 1996, a study of the TS directivity of a 2.2-m-long bottlenose dolphin at an insonifying frequency of 67 kHz was performed. Noting that killer whales, which are dolphins, are morphologically similar to bottlenose dolphins and then assuming allometry, we estimated the relative broadside and tail aspect TS of a 7.5-m-long adult killer whale at an insonifying frequency of 67 kHz to be −8 and −28 dB, respectively. We used a three-layer model for plane wave reflection of sound at 200 kHz from the lung of killer whales to estimate their TS. We assessed the accuracy of our killer whale TS estimates by comparing them with TS estimates of free swimming killer whales obtained using a split-beam active acoustic system operating at 200 kHz. The killer whale TS estimates based on the preliminary model were in good agreement with those obtained for free swimming killer whales.

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Stevens, Tracy A., Deborah A. Duffield, Edward D. Asper, K. Gilbey Hewlett, Al Bolz, Laurie J. Gage, and Gregory D. Bossart. "Preliminary findings of restriction fragment differences in mitochondrial DNA among killer whales (Orcinus orca)." Canadian Journal of Zoology 67, no. 10 (October 1, 1989): 2592–95. http://dx.doi.org/10.1139/z89-365.

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A preliminary assessment of mitochondrial DNA restriction patterns in the killer whale (Orcinus orca) was conducted using 10 captive North Atlantic killer whales from the southeastern coast of Iceland, a captive-born offspring of one of these whales, and 9 North Pacific killer whales. No restriction pattern variation was seen among these whales, using the enzymes BamH I, Bgl II, Hinf I, Kpn I, or Pvu II. Restriction pattern variation was found using the enzyme Hae III. This restriction endonuclease distinguished the North Atlantic killer whales (type 1) from the North Pacific killer whales. The North Pacific killer whales were further differentiated into two groups: those originating from the "resident" communities of the Vancouver Island region (type 2), and those from the "transient" community of Vancouver Island, as well as those stranded along the Oregon coast (type 3). The observed Hae III restriction pattern differences suggest that mitochondrial DNA analysis will be a valuable technique for investigating regional and local distributions of maternal lineages among killer whale pods, especially in the North Pacific.

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LaMere, Sarah A., Judy A. St. Leger, Mark D. Schrenzel, Simon J. Anthony, Bruce A. Rideout, and Daniel R. Salomon. "Molecular Characterization of a Novel Gammaretrovirus in Killer Whales (Orcinus orca)." Journal of Virology 83, no. 24 (October 7, 2009): 12956–67. http://dx.doi.org/10.1128/jvi.01354-09.

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ABSTRACT There are currently no published data documenting the presence of retroviruses in cetaceans, though the occurrences of cancers and immunodeficiency states suggest the potential. We examined tissues from adult killer whales and detected a novel gammaretrovirus by degenerate PCR. Reverse transcription-PCR also demonstrated tissue and serum expression of retroviral mRNA. The full-length sequence of the provirus was obtained by PCR, and a TaqMan-based copy number assay did not demonstrate evidence of productive infection. PCR on blood samples from 11 healthy captive killer whales and tissues from 3 free-ranging animals detected the proviral DNA in all tissues examined from all animals. A survey of multiple cetacean species by PCR for gag, pol, and env sequences showed homologs of this virus in the DNA of eight species of delphinids, pygmy and dwarf sperm whales, and harbor porpoises, but not in beluga or fin whales. Analysis of the bottlenose dolphin genome revealed two full-length proviral sequences with 97.4% and 96.9% nucleotide identity to the killer whale gammaretrovirus. The results of single-cell PCR on killer whale sperm and Southern blotting are also consistent with the conclusion that the provirus is endogenous. We suggest that this gammaretrovirus entered the delphinoid ancestor's genome before the divergence of modern dolphins or that an exogenous variant existed following divergence that was ultimately endogenized. However, the transcriptional activity demonstrated in tissues and the nearly intact viral genome suggest a more recent integration into the killer whale genome, favoring the latter hypothesis. The proposed name for this retrovirus is killer whale endogenous retrovirus.

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Goley, P. Dawn, and Janice M. Straley. "Attack on gray whales (Eschrichtius robustus) in Monterey Bay, California, by killer whales (Orcinus orca) previously identified in Glacier Bay, Alaska." Canadian Journal of Zoology 72, no. 8 (August 1, 1994): 1528–30. http://dx.doi.org/10.1139/z94-202.

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A group of at least 17 killer whales (Orcinus orca) were observed attacking a gray whale (Eschrichtius robustus) mother and calf on 2 May 1992 in Monterey Bay, California, U.S.A. (36°47.90′N, 122°00.17′W). Small groups of killer whales took turns harassing the gray whales and prevented them from leaving the area. Three of the killer whales participating in this attack previously had been photographed on 6 August 1989 in Glacier Bay, Alaska, U.S.A. (58°41′N, 136°04′W). This linear distance nearly doubles the maximum range of movement previously reported for killer whales.

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BALLARD, GRANT, and DAVID G. AINLEY. "Killer whale harrassment of Adélie penguins at Ross Island." Antarctic Science 17, no. 3 (August 17, 2005): 385–86. http://dx.doi.org/10.1017/s0954102005002828.

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On innumerable occasions, Adélie (Pygoscelis adeliae) and emperor penguins (Aptenodytes forsteri) have been observed in close proximity to killer whales (Orcinus orca), with no whale-penguin interactions reported. On the other hand, killer whales reportedly harass and eat seabirds on occasion (Walker 1968: p. 1122, Stacey et al. 1990, Williams et al. 1990). Killer whales are known to prey on young king penguins (A. patagonica) as they are fledging (Guinet 1992, Guinet & Bouvier 1995) and occasionally take emperor penguins (Mikhalev et al. 1981). Thomas et al. (1981) report killer whales chasing Adélies. Here we report the only observations of Adélie-killer whale interactions observed in nine field seasons on Ross Island.

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Bain, David E., Birgit Kriete, and Marilyn E. Dahlheim. "Hearing abilities of killer whales (Orcinus orca)." Journal of the Acoustical Society of America 94, no. 3 (September 1993): 1829. http://dx.doi.org/10.1121/1.407766.

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Samarra, Filipa I. P., Volker B. Deecke, Katja Vinding, Marianne H. Rasmussen, René J. Swift, and Patrick J. O. Miller. "Killer whales (Orcinus orca) produce ultrasonic whistles." Journal of the Acoustical Society of America 128, no. 5 (November 2010): EL205—EL210. http://dx.doi.org/10.1121/1.3462235.

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12

Laidre, Kristin L., Mads Peter Heide-Jørgensen, and Jack R. Orr. "Reactions of Narwhals, Monodon monoceros, to Killer Whale, Orcinus orca, Attacks in the Eastern Canadian Arctic." Canadian Field-Naturalist 120, no. 4 (October 1, 2006): 457. http://dx.doi.org/10.22621/cfn.v120i4.355.

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A Killer Whale attack on Narwhals was observed at Kakiak Point in Admiralty Inlet, Nunavut, Canada, in August 2005. Behavioral responses of both Narwhals and Killer Whales were documented by direct observation. Data collected from Narwhals instrumented with satellite-linked transmitters 5 days prior to the arrival of Killer Whales were used to examine changes in Narwhal movement patterns (e.g., dispersal and clumping) five days before the attack, during the attack, and five days after Killer Whales left the area. A minimum of four Narwhals were killed by 12-15 Killer Whales in a period of 6 hours. Narwhals showed a suite of behavioral changes in the immediate presence of Killer Whales including slow, quiet movements, travel close to the beach (<2 m from shore), use of very shallow water, and formation of tight groups at the surface. These behavioral changes are consistent with Inuit accounts of Killer Whale attacks on Narwhals. During the attack, Narwhals dispersed broadly, the groups were less clumped (standard deviation of inter-whale mean latitudes and longitudes), Narwhal space-use doubled from pre-attack home ranges of 347 km2 to 767 km2 (kernel 50% probability), and Narwhals shifted their distribution further south of the attack site. After the disappearance of Killer Whales, north-south dispersal of Narwhals contracted and was similar to pre-attack levels, total space use decreased slightly (599 km2), yet west-east dispersal remained high. Narwhals were distributed significantly (P < 0.001) more broadly offshore in areas not used before the occurrence of Killer Whales. In general, short-term reactions of Narwhals to Killer Whale presence were obvious; yet normal behavior (as observed from shore) resumed shortly after Killer Whales left the area. Long-term (five day) Narwhal behavioral responses included increased dispersal of Narwhal groups over large offshore areas. This is among the few reports of eyewitness Killer Whale attacks on Narwhals in the high Arctic and is the first time changes in Narwhal behavior have been documented in response to a predation event through the use of satellite telemetry.

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Peterson, Megan J., Franz Mueter, Dana Hanselman, Chris Lunsford, Craig Matkin, and Holly Fearnbach. "Killer whale (Orcinus orca) depredation effects on catch rates of six groundfish species: implications for commercial longline fisheries in Alaska." ICES Journal of Marine Science 70, no. 6 (May 22, 2013): 1220–32. http://dx.doi.org/10.1093/icesjms/fst045.

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Abstract Peterson, M. J., Mueter, F., Hanselman, D., Lunsford, C., Matkin, C., and Fearnbach, H. 2013. Killer whale (Orcinus orca) depredation effects on catch rates of six groundfish species: implications for commercial longline fisheries in Alaska. – ICES Journal of Marine Science, 70: 1220–1232. Killer whale (Orcinus orca) depredation occurs when whales damage or remove fish caught on longline gear. This study uses National Marine Fisheries Service longline survey data from 1998–2011 to explore spatial and temporal trends in killer whale depredation and to quantify the effect of killer whale depredation on catches of six groundfish species within three management areas in Alaska: the Bering Sea, Aleutian Islands and Western Gulf of Alaska. When killer whales were present during survey gear retrieval, whales removed an estimated 54–72% of sablefish (Anoplopoma fimbria), 41–84% of arrowtooth flounder (Atheresthes stomias) and 73% (Bering Sea only) of Greenland turbot (Reinhardtius hippoglossoides). Effects on Pacific halibut (Hippoglossus stenolepis) and Pacific cod (Gadus macrocephalus) were significant in the Western Gulf only with 51% and 46% reductions, respectively. Overall catches (depredated and non-depredated sets) for all groundfish species significantly impacted by killer whale depredation were lower by 9–28% (p < 0.05). Effects on shortspine thornyhead (Sebastolobus alascanus) catches were not significant in any management area (p > 0.05). These results provide insight into the potential impacts of killer whale depredation on fish stock abundance indices and commercially important fisheries in Alaska and will inform future research on apex predator–fisheries interactions.

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Higdon, Jeff W., Kristin H. Westdal, and Steven H. Ferguson. "Distribution and abundance of killer whales (Orcinus orca) in Nunavut, Canada—an Inuit knowledge survey." Journal of the Marine Biological Association of the United Kingdom 94, no. 6 (August 6, 2013): 1293–304. http://dx.doi.org/10.1017/s0025315413000921.

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Traditional ecological knowledge is being increasingly used in wildlife management in northern regions, and Inuit harvesters in Nunavut, Canada, have extensive knowledge about local wildlife species. We collected Inuit knowledge on killer whales (Orcinus orca) through 105 semi-directed interviews in 11 Nunavut communities from 2007 to 2010. Interviewees provided extensive information on killer whale movements, seasonal presence, distribution and abundance in the eastern Canadian Arctic. Observations from different communities were often complementary, and there was consistency in interview comments both within and among regions. Nearly all participants had seen killer whales at least once, and the whales were present every summer (July–September) in all regions, although movements depended on ice conditions. Relative abundance of killer whales varied by region, and they were reported more often in North Baffin communities than in other regions. Killer whales migrated through Hudson Strait and Lancaster Sound following their marine mammal prey. Estimates of local population sizes were variable, with suggested numbers that varied from tens to the low hundreds. Most interviewees in the Foxe Basin, Hudson Bay and north Baffin regions thought that killer whale presence was increasing. In contrast, half the South Baffin interviewees noted declines in past abundance due to the 1977 harvest of 14 whales that became trapped in a saltwater lake. Interviews provided information at a long temporal and wide spatial record. Inuit are reliable observers and continued killer whale research will be most effective if it integrates modern science approaches with the traditional skills, knowledge and experience of Inuit harvesters.

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Lauriano, Giancarlo, Caterina Maria Fortuna, and Marino Vacchi. "Occurrence of killer whales (Orcinus orca) and other cetaceans in Terra Nova Bay, Ross Sea, Antarctica." Antarctic Science 23, no. 2 (November 29, 2010): 139–43. http://dx.doi.org/10.1017/s0954102010000908.

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AbstractDuring January and February 2004, data on presence and distribution of killer whales (Orcinus orca) and other cetaceans were collected by helicopter surveys along the coastline of Terra Nova Bay and adjacent localities (western Ross Sea, Antarctica). A total of 37 sightings of killer whale, of both B and C types, were recorded as well as 17 sightings of Antarctic minke whales (Balaenoptera bonaerensis), nine ofBalaenopteraspp., two of Arnoux’s beaked whale (Berardius arnuxii) and four of undetermined species. The type C killer whale was the most abundant, with 23 sightings, whereas we recorded type B only twice. Group size ranged between 1 and 30 animals, with an average of eight individuals. Seventeen killer whales were photo-identified and 13 resightings occurred during the study period. Killer whales showed a differential pattern in partitioning the study area. Their encounter rate was significantly higher (t-test = 2.6045,P< 0.05) in the northern area extending from Edmonson Point to the Campbell Glacier Tongue (encounter rate, ER = 0.031), compared to the southern area from Mario Zucchelli Station to the Drygalski Ice Tongue (ER = 0.003).

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Desforges, Jean-Pierre, Ailsa Hall, Bernie McConnell, Aqqalu Rosing-Asvid, Jonathan L. Barber, Andrew Brownlow, Sylvain De Guise, et al. "Predicting global killer whale population collapse from PCB pollution." Science 361, no. 6409 (September 27, 2018): 1373–76. http://dx.doi.org/10.1126/science.aat1953.

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Killer whales (Orcinus orca) are among the most highly polychlorinated biphenyl (PCB)–contaminated mammals in the world, raising concern about the health consequences of current PCB exposures. Using an individual-based model framework and globally available data on PCB concentrations in killer whale tissues, we show that PCB-mediated effects on reproduction and immune function threaten the long-term viability of >50% of the world’s killer whale populations. PCB-mediated effects over the coming 100 years predicted that killer whale populations near industrialized regions, and those feeding at high trophic levels regardless of location, are at high risk of population collapse. Despite a near-global ban of PCBs more than 30 years ago, the world’s killer whales illustrate the troubling persistence of this chemical class.

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Lefort, K. J., C. J. D. Matthews, J. W. Higdon, S. D. Petersen, K. H. Westdal, C. J. Garroway, and S. H. Ferguson. "A review of Canadian Arctic killer whale (Orcinus orca) ecology." Canadian Journal of Zoology 98, no. 4 (April 2020): 245–53. http://dx.doi.org/10.1139/cjz-2019-0207.

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The killer whale (Orcinus orca (Linnaeus, 1758)) is a widely distributed marine predator with a broad ecological niche at the species level with evidence of specialization and narrow ecological niches among populations. Their occurrence in Canadian Arctic waters is limited by sea ice and it has been suggested that climate warming, which has caused increases in the area of ice-free water and duration of the ice-free season, has led to an increased killer whale presence during the open-water period. In this review, we summarize our knowledge of Canadian Arctic killer whale demographics and ecology, synthesizing published and previously unpublished information in a single document. More specifically, we summarize our knowledge of killer whale population size and trends, distribution and seasonality (including results from recent satellite-tracking studies), feeding ecology, and threats, and identify research priorities in the Canadian Arctic. Despite increased research efforts during the past decade, our demographic and ecological knowledge remains incomplete. An improved ecological understanding is necessary for effective management of killer whales and their prey, species of ecological, economic, and cultural importance to Canadian Inuit and the marine ecosystem. This knowledge will allow us to better understand the ecological consequences of a changing Arctic climate.

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Brault, Solange, and Hal Caswell. "Pod-Specific Demography of Killer Whales (Orcinus Orca)." Ecology 74, no. 5 (July 1993): 1444–54. http://dx.doi.org/10.2307/1940073.

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Au, Whitlow W. L., John K. B. Ford, and Kelly A. Allman. "Echolocation signals of foraging killer whales (Orcinus orca)." Journal of the Acoustical Society of America 111, no. 5 (2002): 2343. http://dx.doi.org/10.1121/1.4777848.

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Clark, Steven T., and Daniel K. Odell. "Nursing parameters in captive killer whales (Orcinus orca)." Zoo Biology 18, no. 5 (1999): 373–84. http://dx.doi.org/10.1002/(sici)1098-2361(1999)18:5<373::aid-zoo2>3.0.co;2-d.

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Samarra, Filipa I. P., Manuela Bassoi, Julie Béesau, Margrét Ó. Elíasdóttir, Karl Gunnarsson, Marie-Thérèse Mrusczok, Marianne Rasmussen, Jonathan N. Rempel, Baldur Thorvaldsson, and Gísli A. Víkingsson. "Prey of killer whales (Orcinus orca) in Iceland." PLOS ONE 13, no. 12 (December 12, 2018): e0207287. http://dx.doi.org/10.1371/journal.pone.0207287.

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Riesch, Rüdiger, John K. B. Ford, and Frank Thomsen. "Whistle sequences in wild killer whales (Orcinus orca)." Journal of the Acoustical Society of America 124, no. 3 (September 2008): 1822–29. http://dx.doi.org/10.1121/1.2956467.

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Heimlich-Boran, James R. "Behavioral ecology of killer whales (Orcinus orca) in the Pacific Northwest." Canadian Journal of Zoology 66, no. 3 (March 1, 1988): 565–78. http://dx.doi.org/10.1139/z88-084.

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Killer whales (Orcinus orca) were found to use different physiographic regions of their habitat in unique ways. Resident whales fed more in areas of high relief subsurface topography along salmon migratory routes, and may use these geographic features to increase feeding efficiency. Transient whales fed in shallow protected areas around concentrations of their prey, harbor seals (Phoca vitulina). Whales traveled across deep, featureless areas in moving from one feeding area to another. Whales rested depending on the previous sequence of behaviors and played in open water areas or adjacent to feeding areas. The location of food resources and habitats suitable for prey capture appears to be the prime determining factor in the behavioral ecology of these whales. These patterns of behavior most likely represent cultural mechanisms that have been learned through trial and error experiences leading to successful foraging strategies.

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Branstetter, Brian K., Doug Acton, John Stewart, Dorian Houser, Judy St. Ledger, James Finneran, and Keith Jenkins. "Killer whale (Orcinus orca) audiograms." Journal of the Acoustical Society of America 140, no. 4 (October 2016): 3298. http://dx.doi.org/10.1121/1.4970488.

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McCordic, Jessica A., Sean K. Todd, and Peter T. Stevick. "Differential rates of killer whale attacks on humpback whales in the North Atlantic as determined by scarification." Journal of the Marine Biological Association of the United Kingdom 94, no. 6 (August 7, 2013): 1311–15. http://dx.doi.org/10.1017/s0025315413001008.

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As in other populations of killer whales, Orcinus orca, prey selectivity in the North Atlantic population may indicate behaviourally or ecologically distinct types of killer whales. Some killer whale ecotypes are known to prey on large whales, but the ecological impact of such predation events is unknown. Since killer whale attacks on humpback whales, Megaptera novaeangliae, are rarely witnessed, resultant scars may be used to determine the frequency of non-fatal predatory interactions. Using images from the North Atlantic Humpback Whale Catalogue (NAHWC), we examined humpback whale flukes for the presence of rake marks from killer whales (N = 5040). Scarring frequencies range from 2.7 to 17.4% and differ significantly among five regions of the North Atlantic (Gulf of Maine, Canada, West Greenland, Iceland and Norway). The scarring rate in the Canada region is significantly higher than all other regions, and Norway has a significantly lower scarring rate than all other regions, despite more frequently reported killer whale sightings in that region. Within the western North Atlantic, Canada has a scarring rate nearly twice that of either the Gulf of Maine or West Greenland. These data may reflect differential prey choice among killer whale ecotypes and/or the distribution of specific ecotypes across the North Atlantic basin.

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Weir, Caroline R., Tim Collins, Inês Carvalho, and Howard C. Rosenbaum. "Killer whales (Orcinus orca) in Angolan and Gulf of Guinea waters, tropical West Africa." Journal of the Marine Biological Association of the United Kingdom 90, no. 8 (June 17, 2010): 1601–11. http://dx.doi.org/10.1017/s002531541000072x.

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Killer whales Orcinus orca are considered to be relatively uncommon in tropical waters. Few sightings have been reported from the west coast of Africa due to a paucity of survey coverage. We present data on 32 killer sightings from tropical waters off Angola (N = 18), Gabon (N = 7), São Tomé (N = 6) and Cameroon (N = 1), comprising a combination of dedicated survey sightings (N = 21) and reliable anecdotal records (n = 11). Killer whales were reported from coastal waters, the shelf edge and deep, oceanic areas. Sightings indicate a probable year-round occurrence of killer whales within the region. Mean group size was 5.6 animals. There was no difference in group size between sightings in waters >200 m deep and those on the continental shelf. No photo-identification matches were found between Angola, Gabon and São Tomé. Re-sightings of two individuals occurred annually in São Tomé during 2002–2004. Killer whales had external appearance consistent with the Type A nominate species form. Antagonistic encounters were recorded between killer whales and humpback whales Megaptera novaeangliae off Angola, Gabon and Cameroon, and with sperm whales Physeter macrocephalus off Angola. Predation on ocean sunfish Mola mola was recorded in São Tomé, and possible predation on sharks was recorded twice in Gabon.

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Wellard, Rebecca, Robert L. Pitman, John Durban, and Christine Erbe. "Cold call: the acoustic repertoire of Ross Sea killer whales ( Orcinus orca, Type C) in McMurdo Sound, Antarctica." Royal Society Open Science 7, no. 2 (February 2020): 191228. http://dx.doi.org/10.1098/rsos.191228.

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Killer whales ( Orcinus orca ) are top marine predators occurring globally. In Antarctic waters, five ecotypes have been described, with Type C being the smallest form of killer whale known. Acoustic recordings of nine encounters of Type C killer whales were collected in 2012 and 2013 in McMurdo Sound, Ross Sea. In a combined 3.5 h of recordings, 6386 killer whale vocalizations were detected and graded based on their signal-to-noise ratio. Spectrograms of the highest-quality calls were examined for characteristic patterns yielding a catalogue of 28 call types (comprising 1250 calls). Acoustic parameters of each call were measured and summarized by call type. Type C killer whales produced complex calls, consisting of multiple frequency-modulated, amplitude-modulated and pulsed components. Often, two components occurred simultaneously, forming a biphonation; although the biphonic components did not necessarily start and end together, with one component lasting over several others. The addition and deletion of components yielded call subtypes. Call complexity appears stable over time and may be related to feeding ecology. Characterization of the Type C acoustic repertoire is an important step for the development of passive acoustic monitoring of the diverse assemblage of killer whale ecotypes in Antarctica's rapidly changing marine ecosystems.

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Shulezhko, Tatiana S., Peter A. Permyakov, Sergey D. Ryazanov, and Vladimir N. Burkanov. "Bigg’s Killer Whales (Orcinus orca) in the Kuril Islands." Aquatic Mammals 44, no. 3 (May 15, 2018): 267–78. http://dx.doi.org/10.1578/am.44.3.2018.267.

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Keith, M., M. N. Bester, P. A. Bartlett, and D. Baker. "Killer whales (Orcinus orca) at Marion Island, Southern Ocean." African Zoology 36, no. 2 (October 2001): 163–75. http://dx.doi.org/10.1080/15627020.2001.11657134.

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Clark, Steven T., Daniel K. Odell, and C. Thad Lacinak. "ASPECTS OF GROWTH IN CAPTIVE KILLER WHALES (ORCINUS ORCA)." Marine Mammal Science 16, no. 1 (January 2000): 110–23. http://dx.doi.org/10.1111/j.1748-7692.2000.tb00907.x.

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Mobley, Joseph R., Lori Mazzuca, Alison S. Craig, Michael W. Newcomer, and Scott S. Spitz. "Killer Whales (Orcinus orca) Sighted West of Ni'ihau, Hawai'i." Pacific Science 55, no. 3 (2001): 301–3. http://dx.doi.org/10.1353/psc.2001.0023.

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Young, Brent G., Sarah M. E. Fortune, William R. Koski, Stephen A. Raverty, Ricky Kilabuk, and Steven H. Ferguson. "Evidence of killer whale predation on a yearling bowhead whale in Cumberland Sound, Nunavut." Arctic Science 6, no. 1 (March 1, 2020): 53–61. http://dx.doi.org/10.1139/as-2019-0014.

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Accounts of killer whale (Orcinus orca) predation on marine mammals in the Canadian Arctic are relatively uncommon. Although second-hand reports of killer whale predation events in the Arctic are more common in recent years, these observations are generally poorly documented and the outcome of attacks are often unknown. On 12 August 2016, a floating bowhead whale (Balaena mysticetus) carcass was found off-shore in Cumberland Sound, Nunavut — presumably predated by killer whales that were sighted in the area. Inspection of the carcass revealed injuries consistent with published accounts of killer whale predation on large whales and observations of killer whale predation on bowheads described in Inuit traditional knowledge. The bowhead was male, 6.1 m long in good nutritional condition and estimated between 14 and 16 months old. As a recently weaned yearling, this whale would have been highly vulnerable to killer whale predation. With decreasing summer sea ice making some areas of the Arctic more accessible, the incursion and presence of killer whales in the Arctic is expected to increase. A better understanding of Arctic killer whale predation pressure is needed to predict the potential impact they will have on the eastern Canada–west Greenland bowhead population as well as on other marine mammal prey.

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Ford, John KB, Graeme M. Ellis, Lance G. Barrett-Lennard, Alexandra B. Morton, Rod S. Palm, and Kenneth C. Balcomb III. "Dietary specialization in two sympatric populations of killer whales (Orcinus orca) in coastal British Columbia and adjacent waters." Canadian Journal of Zoology 76, no. 8 (August 1, 1998): 1456–71. http://dx.doi.org/10.1139/z98-089.

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Two forms of killer whale (Orcinus orca), resident and transient, occur sympatrically in coastal waters of British Columbia, Washington State, and southeastern Alaska. The two forms do not mix, and differ in seasonal distribution, social structure, and behaviour. These distinctions have been attributed to apparent differences in diet, although no comprehensive comparative analysis of the diets of the two forms had been undertaken. Here we present such an analysis, based on field observations of predation and on the stomach contents of stranded killer whales collected over a 20-year period. In total, 22 species of fish and 1 species of squid were documented in the diet of resident-type killer whales; 12 of these are previously unrecorded as prey of O. orca. Despite the diversity of fish species taken, resident whales have a clear preference for salmon prey. In field observations of feeding, 96% of fish taken were salmonids. Six species of salmonids were identified from prey fragments, with chinook salmon (Oncorhynchus tshawytscha) being the most common. The stomach contents of stranded residents also indicated a preference for chinook salmon. On rare occasions, resident whales were seen to harass marine mammals, but no kills were confirmed and no mammalian remains were found in the stomachs of stranded residents. Transient killer whales were observed to prey only on pinnipeds, cetaceans, and seabirds. Six mammal species were taken, with over half of observed attacks involving harbour seals (Phoca vitulina). Seabirds do not appear to represent a significant prey resource. This study thus reveals the existence of strikingly divergent prey preferences of resident and transient killer whales, which are reflected in distinctive foraging strategies and related sociobiological traits of these sympatric populations.

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Seco Pon, Juan Pablo, and Marco Favero. "South American sea lions (Otaria flavescens) and killer whales (Orcinus orca) attending chub mackerel (Scomber japonicus) commercial trawl fisheries over the Patagonian Shelf: a first report." Latin American Journal of Aquatic Mammals 10, no. 1 (August 24, 2015): 48–51. http://dx.doi.org/10.5597/lajam00193.

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Killer whale-seal interactions have been reported for almost all pinniped species globally. However the literature on offshore interactions between killer whales and sea lions is rare for the South Atlantic, particularly in Argentine waters. Here we report for the first time the harassment of a South American sea lion (Otaria flavescens) by killer whales (Ornicus orca) while attending commercial fishing vessels in offshore national waters and describe a novel sea lion antipredator behaviour. These observations were made during an ongoing survey to assess seabird-fisheries interactions in the commercial trawl fishery off Argentina.

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Matthews, Cory J. D., Jack W. Lawson, and Steven H. Ferguson. "Amino acid δ15N differences consistent with killer whale ecotypes in the Arctic and Northwest Atlantic." PLOS ONE 16, no. 4 (April 2, 2021): e0249641. http://dx.doi.org/10.1371/journal.pone.0249641.

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Ecotypes are groups within a species with different ecological adaptations than their conspecifics. Eastern North Pacific (ENP) killer whale (Orcinus orca) ecotypes differ in their diet, behavior, and morphology, but the same is not known for this species in the eastern Canadian Arctic (ECA) and Northwest Atlantic (NWA). Using compound-specific stable isotope analysis (CSIA) of amino acids (AAs), we compared δ15N patterns of the primary trophic and source AA pair, glutamic acid/glutamine (Glx) and phenylalanine (Phe), in dentine collagen of (1) sympatric ENP killer whale ecotypes with well-characterized diet differences and (2) ECA/NWA killer whales with unknown diets. δ15NGlx-Phe was significantly higher in the ENP fish-eating (FE) than mammal-eating (ME) ecotype (19.2 ± 0.4‰ vs. 13.5 ± 0.7‰, respectively). Similar bimodal variation in δ15NGlx-Phe indicated analogous dietary divisions among ECA/NWA killer whales, with two killer whales having higher δ15NGlx-Phe (16.5 ± 0.0‰) than the others (13.5 ± 0.6‰). Inferences of dietary divisions between these killer whales were supported by parallel differences in threonine δ15N (–33.5 ± 1.6‰ and –40.4 ± 1.1‰, respectively), given the negative correlation between δ15NThr and TP across a range of marine consumers. CSIA-AA results for ECA/NWA whales, coupled with differences in tooth wear (a correlate for diet), are consistent with ecotype characteristics reported in ENP and other killer whale populations, thus adding to documented ecological divergence in this species worldwide.

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Mäkeläinen, Pirjo, Ruth Esteban, Andrew D. Foote, Sanna Kuningas, Julius Nielsen, Filipa I. P. Samarra, Tiu Similä, Nienke C. F. van Geel, and Gíslia A. Víkingsson. "A comparison of pigmentation features among North Atlantic killer whale (Orcinus orca) populations." Journal of the Marine Biological Association of the United Kingdom 94, no. 6 (April 29, 2014): 1335–41. http://dx.doi.org/10.1017/s0025315414000277.

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Here we present a comparison of saddle and eye patch patterns of killer whales from Norwegian, Icelandic, British, Spanish and Greenlandic waters. We found only a small amount of variation in saddle patch shapes, which may reflect a recent phylogenetic divergence from the most recent common ancestor. Eye patch shapes were more variable than saddle patches in small details. Most individuals had eye patches with parallel orientation, with the exception of a small group of killer whales from the Hebrides, which, as previously reported, had sloping eye patches that sloped downward at the posterior end. This differentiation in pigmentation patterns of the Hebridean killer whales from neighbouring populations could reflect one or more of several evolutionary processes, including a deeper phylogenetic divergence, low gene flow with other local populations and drift.

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Jett, John, and Jeffrey Ventre. "Captive killer whale ( Orcinus orca ) survival." Marine Mammal Science 31, no. 4 (April 20, 2015): 1362–77. http://dx.doi.org/10.1111/mms.12225.

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Branstetter, Brian K., Judy St. Leger, Doug Acton, John Stewart, Dorian Houser, James J. Finneran, and Keith Jenkins. "Killer whale (Orcinus orca) behavioral audiograms." Journal of the Acoustical Society of America 141, no. 4 (April 2017): 2387–98. http://dx.doi.org/10.1121/1.4979116.

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Ridoux, Vincent. "Feeding association between seabirds and killer whales, Orcinus orca, around subantarctic Crozet Islands." Canadian Journal of Zoology 65, no. 8 (August 1, 1987): 2113–15. http://dx.doi.org/10.1139/z87-324.

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Twenty-nine observations of killer whale (Orcinus orca) pods and associated bird flocks were made from March 1982 to February 1983 from the coast of Possession Island (Crozet Archipelago). Coastal foraging birds, such as giant petrels (Macronectes sp.), Cape pigeon (Daption capense), and kelp gull (Larus dominicanus), are more often associated with feeding pods than with nonfeeding ones, while pelagic species like the white-chinned petrel (Procellaria aequinoctialis) may deliberately follow the whales and wait for floating offal. The black-browed albatross (Diomedea melanophrys), which is somewhat intermediate between coastal and pelagic birds, shows components of both strategies.

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Lauriano, Giancarlo, Marino Vacchi, David Ainley, and Grant Ballard. "Short Note: Observations of top predators foraging on fish in the pack ice of the southern Ross Sea." Antarctic Science 19, no. 4 (July 13, 2007): 439–40. http://dx.doi.org/10.1017/s0954102007000508.

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New micro-technology with links to satellites has revolutionized the collection of information on the foraging movements of marine animals, but observations of actual foraging are still very rare. Here we describe foraging by killer whales (Orcinus orca(L.)), minke whales (Balaenoptera bonaerensisBurmeister), Adélie penguins (Pygoscelis adeliae(Hombron & Jacquinot)) and emperor penguins (Aptenodytes forsteriGray), in all cases we believe feeding on fish, in the south-western Ross Sea, Antarctica.

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Passadore, Cecilia, Andrés Domingo, María Szephegyi, and Eduardo R. Secchi. "Influence of environmental and longline fishing operational variables on the presence of killer whales (Orcinus orca) in south-western Atlantic." Journal of the Marine Biological Association of the United Kingdom 94, no. 6 (November 27, 2012): 1267–76. http://dx.doi.org/10.1017/s002531541200166x.

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Killer whale (Orcinus orca) is frequently encountered in coastal and high productive pelagic waters, near the shelf break. In the south-western Atlantic Ocean, spatial and temporal occurrence patterns are poorly known. However, the monitoring of the interaction between killer whales and longline fishery suggests that the species is frequent in this region. We analysed the killer whale presence within the Uruguayan pelagic longline fishing zone. Data were collected from 1996 to 2007, during 2189 fishing events, by vessel skippers and on-board observers. We estimated the sighting rate (SR = sightings days/fishing days * 100) for different time scales and in 1 × 1 degree grids. Generalized linear models were used to evaluate the effect of spatial, temporal, environmental and operational variables on the species presence. Killer whales were sighted in 100 fishing days (SR = 4.5%), this occurrence being explained by distance from shore and sea surface temperature, varying among months and fishing boats. Although sightings occurred year round, they were more frequent in autumn and winter, at 150–400 nautical miles (nm) from shore (mean = 250 nm) and in waters with temperatures ranging from 19 to 24°C (mean = 22°C). Sets took place between 19°–40°S and 21°–54°W, while killer whales occurred mostly from 34°–37°S and 48°–53°W. In this region, the high productive Brazil—Malvinas Confluence Zone is located, and concentrates fishing effort and also killer whales.

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Tixier, Paul, Mary-Anne Lea, Mark A. Hindell, Christophe Guinet, Nicolas Gasco, Guy Duhamel, and John P. Y. Arnould. "Killer whale (Orcinus orca) interactions with blue-eye trevalla (Hyperoglyphe antarctica) longline fisheries." PeerJ 6 (August 8, 2018): e5306. http://dx.doi.org/10.7717/peerj.5306.

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Over the past five decades, marine mammal interactions with fisheries have become a major human-wildlife conflict globally. The emergence of longline fishing is concomitant with the development of depredation-type interactions i.e., marine mammals feeding on fish caught on hooks. The killer whale (Orcinus orca) is one of the species most involved in depredation on longline fisheries. The issue was first reported in high latitudes but, with increasing expansion of this fishing method, other fisheries have begun to experience interactions. The present study investigated killer whale interactions with two geographically isolated blue-eye trevalla (Hyperoglyphe antarctica) fisheries operating in temperate waters off Amsterdam/St. Paul Islands (Indian Ocean) and south-eastern Australia. These two fisheries differ in the fishing technique used (vertical vs. demersal longlines), effort, catch, fleet size and fishing area size. Using 7-year (2010–16) long fishing and observation datasets, this study estimated the levels of killer whale interactions and examined the influence of spatio-temporal and operational variables on the probability of vessels to experience interactions. Killer whales interactions occurred during 58.4% and 21.2% of all fishing days, and over 94% and 47.4% of the fishing area for both fisheries, respectively. In south-eastern Australia, the probability of occurrence of killer whale interactions during fishing days varied seasonally with a decrease in spring, increased with the daily fishing effort and decreased with the distance travelled by the vessel between fishing days. In Amsterdam/St. Paul, this probability was only influenced by latitude, with an increase in the southern part of the area. Together, these findings document two previously unreported cases of high killer whale depredation, and provide insights on ways to avoid the issue. The study also emphasizes the need to further examine the local characteristics of fisheries and the ecology of local depredating killer whale populations in as important drivers of depredation.

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Kuningas, Sanna, Tiu Similä, and Philip S. Hammond. "Population size, survival and reproductive rates of northern Norwegian killer whales (Orcinus orca) in 1986–2003." Journal of the Marine Biological Association of the United Kingdom 94, no. 6 (August 7, 2013): 1277–91. http://dx.doi.org/10.1017/s0025315413000933.

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A long-term photo-identification study of killer whales (Orcinus orca) in northern Norway was initiated in 1986, when their prey the Norwegian spring-spawning herring (Clupea harengus) started to winter in a complex fjord system. The aim of this work was to estimate population size and apparent survival rates in this killer whale population using photo-identification and mark–recapture techniques with data collected during October–December 1986–2003. Total population size was estimated to be highest in 2003: 731 individuals (SE = 139, 95% CI = 505–1059) using a model taking heterogeneity of capture probabilities into account. Apparent survival of adult males and adult females was estimated using the Cormack–Jolly–Seber model as 0.971 (SE = 0.008) and 0.977 (SE = 0.009), respectively. Calving intervals ranged from 3 to 14 years (mean = 5.06, SE = 0.722). These are the first estimates of northern Norwegian killer whale population parameters, allowing their dynamics to be investigated and comparisons to be made with killer whale populations globally.

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Mul, E., MA Blanchet, BT McClintock, WJ Grecian, M. Biuw, and A. Rikardsen. "Killer whales are attracted to herring fishing vessels." Marine Ecology Progress Series 652 (October 15, 2020): 1–13. http://dx.doi.org/10.3354/meps13481.

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Marine mammals and fisheries often target the same resources, which can lead to operational interactions. Potential consequences of operational interaction include entanglements and damaged or reduced catches but also enhanced foraging opportunities, which can attract marine mammals to fishing vessels. Responsible fisheries management therefore requires detailed knowledge of the impact of these interactions. In northern Norway, killer whales Orcinus orca are frequently observed in association with large herring aggregations during the winter. We use a combination of biotelemetry and fisheries data to study if, to what extent and at what distances killer whales are attracted to fishing activity. Twenty-five satellite transmitters were deployed on killer whales at herring overwintering and spawning grounds, often near fishing vessels. Over 50% of the killer whale core areas of high usage overlapped with the fisheries core areas, and individual whales spent up to 34% of their time close to active fishing. We used a 3-state hidden Markov model to assess whether killer whale movements were biased towards fishing activities. Of the overall whale movements, 15% (CI = 11-21%) were biased towards fishing activities, with marked heterogeneity among individuals (0-57%). During periods of active fishing, whale movements were biased towards fishing events 44% (CI = 24-66%) of the time, with individual percentages ranging from 0 to 79%. Whales were more likely to be attracted when they were within 20 km. This information can be used in fishery management to consider potential consequences for fishers and whales.

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Ford, John K. B., Graeme M. Ellis, Peter F. Olesiuk, and Kenneth C. Balcomb. "Linking killer whale survival and prey abundance: food limitation in the oceans' apex predator?" Biology Letters 6, no. 1 (September 15, 2009): 139–42. http://dx.doi.org/10.1098/rsbl.2009.0468.

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Killer whales ( Orcinus orca ) are large predators that occupy the top trophic position in the world's oceans and as such may have important roles in marine ecosystem dynamics. Although the possible top-down effects of killer whale predation on populations of their prey have received much recent attention, little is known of how the abundance of these predators may be limited by bottom-up processes. Here we show, using 25 years of demographic data from two populations of fish-eating killer whales in the northeastern Pacific Ocean, that population trends are driven largely by changes in survival, and that survival rates are strongly correlated with the availability of their principal prey species, Chinook salmon ( Oncorhynchus tshawytscha ). Our results suggest that, although these killer whales may consume a variety of fish species, they are highly specialized and dependent on this single salmonid species to an extent that it is a limiting factor in their population dynamics. Other ecologically specialized killer whale populations may be similarly constrained to a narrow range of prey species by culturally inherited foraging strategies, and thus are limited in their ability to adapt rapidly to changing prey availability.

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Filatova, Olga A., Ivan D. Fedutin, Olga V. Titova, Brad Siviour, Alexandr M. Burdin, and Erich Hoyt. "White Killer Whales (Orcinus orca) in the Western North Pacific." Aquatic Mammals 42, no. 3 (September 1, 2016): 350–56. http://dx.doi.org/10.1578/am.42.3.2016.350.

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Sitt, Tatjana, Lizabeth Bowen, Chia-Shan Lee, Myra T. Blanchard, James McBain, Christopher Dold, and Jeffrey L. Stott. "Longitudinal evaluation of leukocyte transcripts in killer whales (Orcinus Orca)." Veterinary Immunology and Immunopathology 175 (July 2016): 7–15. http://dx.doi.org/10.1016/j.vetimm.2016.04.011.

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O'Sullivan, Sean, and Keith D. Mullin. "KILLER WHALES (ORCINUS ORCA) IN THE NORTHERN GULF OF MEXICO." Marine Mammal Science 13, no. 1 (January 1997): 141–47. http://dx.doi.org/10.1111/j.1748-7692.1997.tb00618.x.

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Van Parijs, Sofie M., Teo Leyssen, and Tiu Similä. "Sounds produced by Norwegian killer whales,Orcinus orca, during capture." Journal of the Acoustical Society of America 116, no. 1 (July 2004): 557–60. http://dx.doi.org/10.1121/1.1763954.

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Kasting, Norman W., Shelley A. L. Adderley, Tammy Safford, and K. Gilbey Hewlett. "Thermoregulation in Beluga (Delphinapterus leucas) and Killer (Orcinus orca) Whales." Physiological Zoology 62, no. 3 (May 1989): 687–701. http://dx.doi.org/10.1086/physzool.62.3.30157921.

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Journal articles on the topic 'Killer whales (Orcinus orca)'

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