A review of Canadian Arctic killer whale (Orcinus orca) ecology

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summarize our knowledge of Canadian Arctic killer whale demographics and ecology, synthesizing published and previously unpublished information in a single document.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.

Download Full-text

Amino acid δ15N differences consistent with killer whale ecotypes in the Arctic and Northwest Atlantic

PLoS ONE ◽

10.1371/journal.pone.0249641 ◽

2021 ◽

Vol 16 (4) ◽

pp. e0249641

Author(s):

Cory J. D. Matthews ◽

Jack W. Lawson ◽

Steven H. Ferguson

Keyword(s):

Killer Whale ◽

Isotope Analysis ◽

Canadian Arctic ◽

Tooth Wear ◽

Orcinus Orca ◽

The Arctic ◽

Killer Whales ◽

Northwest Atlantic ◽

Ecological Adaptations ◽

Bimodal Variation

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.

Download Full-text

Evidence of killer whale predation on a yearling bowhead whale in Cumberland Sound, Nunavut

Arctic Science ◽

10.1139/as-2019-0014 ◽

2020 ◽

Vol 6 (1) ◽

pp. 53-61 ◽

Cited By ~ 3

Author(s):

Brent G. Young ◽

Sarah M.E. Fortune ◽

William R. Koski ◽

Stephen A. Raverty ◽

Ricky Kilabuk ◽

...

Keyword(s):

Marine Mammals ◽

Killer Whale ◽

Canadian Arctic ◽

Bowhead Whale ◽

Orcinus Orca ◽

The Arctic ◽

Killer Whales ◽

Eastern Canada ◽

Cumberland Sound ◽

Potential Impact

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.

Download Full-text

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 ◽

10.1017/s0025315413000921 ◽

2013 ◽

Vol 94 (6) ◽

pp. 1293-1304 ◽

Cited By ~ 14

Author(s):

Jeff W. Higdon ◽

Kristin H. Westdal ◽

Steven H. Ferguson

Keyword(s):

Killer Whale ◽

Local Population ◽

Modern Science ◽

Orcinus Orca ◽

Ecological Knowledge ◽

Killer Whales ◽

Northern Regions ◽

Population Sizes ◽

Ice Conditions ◽

Inuit Knowledge

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.

Download Full-text

Satellite tracking of a killer whale (Orcinus orca) in the eastern Canadian Arctic documents ice avoidance and rapid, long-distance movement into the North Atlantic

Polar Biology ◽

10.1007/s00300-010-0958-x ◽

2011 ◽

Vol 34 (7) ◽

pp. 1091-1096 ◽

Cited By ~ 53

Author(s):

Cory J. D. Matthews ◽

Sebastián P. Luque ◽

Stephen D. Petersen ◽

Russel D. Andrews ◽

Steven H. Ferguson

Keyword(s):

North Atlantic ◽

Killer Whale ◽

Canadian Arctic ◽

Satellite Tracking ◽

Orcinus Orca ◽

Long Distance ◽

The North ◽

The North Atlantic ◽

Long Distance Movement ◽

Eastern Canadian Arctic

Download Full-text

Killer whale (Orcinus orca) photo-identification in the eastern Canadian Arctic

Polar Research ◽

10.3402/polar.v30i0.7203 ◽

2011 ◽

Vol 30 (1) ◽

pp. 7203 ◽

Cited By ~ 13

Author(s):

BrentG. Young ◽

JeffW. Higdon ◽

StevenH. Ferguson

Keyword(s):

Killer Whale ◽

Canadian Arctic ◽

Orcinus Orca ◽

Photo Identification ◽

Eastern Canadian Arctic

Download Full-text

Passive acoustic monitoring of killer whales (Orcinus orca) reveals year-round distribution and residency patterns in the Gulf of Alaska

Scientific Reports ◽

10.1038/s41598-021-99668-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hannah J. Myers ◽

Daniel W. Olsen ◽

Craig O. Matkin ◽

Lara A. Horstmann ◽

Brenda Konar

Keyword(s):

Killer Whale ◽

Marine Ecosystem ◽

Distribution Patterns ◽

Gulf Of Alaska ◽

Acoustic Monitoring ◽

Orcinus Orca ◽

Killer Whales ◽

Passive Acoustic Monitoring ◽

The North ◽

Passive Acoustic

AbstractKiller whales (Orcinus orca) are top predators throughout the world’s oceans. In the North Pacific, the species is divided into three ecotypes—resident (fish-eating), transient (mammal-eating), and offshore (largely shark-eating)—that are genetically and acoustically distinct and have unique roles in the marine ecosystem. In this study, we examined the year-round distribution of killer whales in the northern Gulf of Alaska from 2016 to 2020 using passive acoustic monitoring. We further described the daily acoustic residency patterns of three killer whale populations (southern Alaska residents, Gulf of Alaska transients, and AT1 transients) for one year of these data. Highest year-round acoustic presence occurred in Montague Strait, with strong seasonal patterns in Hinchinbrook Entrance and Resurrection Bay. Daily acoustic residency times for the southern Alaska residents paralleled seasonal distribution patterns. The majority of Gulf of Alaska transient detections occurred in Hinchinbrook Entrance in spring. The depleted AT1 transient killer whale population was most often identified in Montague Strait. Passive acoustic monitoring revealed that both resident and transient killer whales used these areas much more extensively than previously known and provided novel insights into high use locations and times for each population. These results may be driven by seasonal foraging opportunities and social factors and have management implications for this species.

Download Full-text

Surface-Based Observations Can Be Used to Assess Behavior and Fine-Scale Habitat Use by an Endangered Killer Whale (Orcinus orca) Population

Aquatic Mammals ◽

10.1578/am.42.2.2016.168 ◽

2016 ◽

Vol 42 (2) ◽

pp. 168-183 ◽

Cited By ~ 3

Author(s):

Dawn P. Noren ◽

Donna D. W. Hauser

Keyword(s):

Habitat Use ◽

Killer Whale ◽

Orcinus Orca ◽

Fine Scale

Download Full-text

Family feud: permanent group splitting in a highly philopatric mammal, the killer whale (Orcinus orca)

Behavioral Ecology and Sociobiology ◽

10.1007/s00265-021-02992-8 ◽

2021 ◽

Vol 75 (3) ◽

Author(s):

Eva H. Stredulinsky ◽

Chris T. Darimont ◽

Lance Barrett-Lennard ◽

Graeme M. Ellis ◽

John K. B. Ford

Keyword(s):

Killer Whale ◽

Group Structure ◽

Group Living ◽

Orcinus Orca ◽

Learning Approaches ◽

Killer Whales ◽

Internal Factors ◽

Individual Fitness ◽

Leadership Experience

Abstract For animals that tend to remain with their natal group rather than individually disperse, group sizes may become too large to benefit individual fitness. In such cases, group splitting (or fission) allows philopatric animals to form more optimal group sizes without sacrificing all familiar social relationships. Although permanent group splitting is observed in many mammals, it occurs relatively infrequently. Here, we use combined generalized modeling and machine learning approaches to provide a comprehensive examination of group splitting in a population of killer whales (Orcinus orca) that occurred over three decades. Fission occurred both along and across maternal lines, where animals dispersed in parallel with their closest maternal kin. Group splitting was more common: (1) in larger natal groups, (2) when the common maternal ancestor was no longer alive, and (3) among groups with greater substructuring. The death of a matriarch did not appear to immediately trigger splitting. Our data suggest intragroup competition for food, leadership experience and kinship are important factors that influence group splitting in this population. Our approach provides a foundation for future studies to examine the dynamics and consequences of matrilineal fission in killer whales and other taxa. Significance statement Group living among mammals often involves long-term social affiliation, strengthened by kinship and cooperative behaviours. As such, changes in group membership may have significant consequences for individuals’ fitness and a population’s genetic structure. Permanent group splitting is a complex and relatively rare phenomenon that has yet to be examined in detail in killer whales. In the context of a growing population, in which offspring of both sexes remain with their mothers for life, we provide the first in-depth examination of group splitting in killer whales, where splitting occurs both along and across maternal lines. We also undertake the first comprehensive assessment of how killer whale intragroup cohesion is influenced by both external and internal factors, including group structure, population and group demography, and resource abundance.

Download Full-text