Baleen Whales Research Articles

Morphology of nares associated with stereo-olfaction in baleen whales.

The sensory mechanisms used by baleen whales (Mysticeti) for locating ephemeral, dense prey patches in vast marine habitats are poorly understood. Baleen whales have a functional olfactory system with paired rather than single blowholes (nares), potentially enabling stereo-olfaction. Dimethyl sulfide (DMS) is an odorous gas emitted by phytoplankton in response to grazing by zooplankton. Some seabirds use DMS to locate prey, but this ability has not been demonstrated in whales. For 14 extant species of baleen whale, nares morphometrics (imagery from unoccupied aerial systems, UAS) was related to published trophic level indices using Bayesian phylogenetic mixed modelling. A significant negative relationship was found between nares width and whale trophic level (β = -0.08, lower 95% CI = -0.13, upper 95% CI = -0.03), corresponding with a 39% increase in nares width from highest to lowest trophic level. Thus, species with nasal morphology best suited to stereo-olfaction are more zooplanktivorous. These findings provide evidence that some baleen whale species may be able to localize odorants e.g. DMS. Our results help direct future behavioural trials of olfaction in baleen whales, by highlighting the most appropriate species to study. This is a research priority, given the potential for DMS-mediated plastic ingestion by whales.

A feeding organ the basihyal and thyrohyal tells which size of prey do true baleen whales (Cetacea, Chaeomysticeti) eat

A feeding organ the basihyal and thyrohyal tells which size of prey do true baleen whales (Cetacea, Chaeomysticeti) eat

Proteome profiling reveals opportunities to investigate biomarkers of oxidative stress and immune responses in blubber biopsies from free-ranging baleen whales.

Over 25% of cetacean species worldwide are listed as critically endangered, endangered or vulnerable by the International Union for Conservation of Nature. Objective and widely applicable tools to assess cetacean health are therefore vital for population monitoring and to inform conservation initiatives. Novel blubber biomarkers of physiological state are examples of such tools that could be used to assess overall health. Proteins extracted from blubber likely originate from both the circulation and various cell types within the tissue itself, and their expression is responsive to signals originating from other organs and the nervous system. Blubber proteins can therefore capture information on physiological stressors experienced by individuals at the time of sampling. For the first time, we assess the feasibility of applying shotgun proteomics to blubber biopsy samples collected from free-ranging baleen whales. Samples were collected from minke whales (Balaenoptera acutorostrata) (n = 10) in the Gulf of St Lawrence, Canada. Total protein was extracted using a RIPA cell lysis and extraction buffer-based protocol. Extracted proteins were separated and identified using nanoflow Liquid Chromatography Electrospray Ionization in tandem with Mass Spectrometry. We mapped proteins to known biological pathways and determined whether they were significantly enriched based on the proteome profile. A pathway enrichment map was created to visualize overlap in tissue-level biological processes. Amongst the most significantly enriched biological pathways were those involved in immune system function: inflammatory responses, leukocyte-mediated immunity and the humoral immune response. Pathways associated with responses to oxidative stress were also enriched. Using a suite of such protein biomarkers has the potential to better assess the overall health and physiological state of live individuals through remote biopsy sampling. This information is vital for population health assessments to predict population trajectories, and ultimately guide and monitor conservation priorities and initiatives.

Seasonal acoustic presence of marine mammals at the South Orkney Islands, Scotia Sea.

Increased knowledge about marine mammal seasonal distribution and species assemblage from the South Orkney Islands waters is needed for the development of management regulations of the commercial fishery for Antarctic krill (Euphausia superba) in this region. Passive acoustic monitoring (PAM) data were collected during the autumn and winter seasons in two consecutive years (2016, 2017), which represented highly contrasting environmental conditions due to the 2016 El Niño event. We explored differences in seasonal patterns in marine mammal acoustic presence between the two years in context of environmental cues and climate variability. Acoustic signals from five baleen whale species, two pinniped species and odontocete species were detected and separated into guilds. Although species diversity remained stable over time, the ice-avoiding and ice-affiliated species dominated before and after the onset of winter, respectively, and thus demonstrating a shift in guild composition related to season. Herein, we provide novel information about local marine mammal species diversity, community structure and residency times in a krill hotspot. Our study also demonstrates the utility of PAM data and its usefulness in providing new insights into the marine mammal habitat use and responses to environmental conditions, which are essential knowledge for the future development of a sustainable fishery management in a changing ecosystem.

Demographic and physiological signals of reproductive events in humpback whales on a southwest pacific breeding ground.

The field of marine mammal conservation has dramatically benefited from the rapid advancement of methods to assess the reproductive physiology of individuals and populations from steroid hormones isolated from minimally invasive skin-blubber biopsy samples. Historically, this vital information was only available from complete anatomical and physiological investigations of samples collected during commercial or indigenous whaling. Humpback whales (Megaptera novaeangliae) are a migratory, cosmopolitan species that reproduce in warm, low-latitude breeding grounds. New Caledonia is seasonally visited by a small breeding sub-stock of humpback whales, forming part of the endangered Oceania subpopulation. To better understand the demographic and seasonal patterns of reproductive physiology in humpback whales, we quantified baseline measurements of reproductive hormones (progesterone-P4, testosterone-T and 17β-estradiol-E2) using an extensive archive of skin-blubber biopsy samples collected from female humpback whales in New Caledonia waters between 2016 and 2019 (n = 194). We observed significant differences in the P4, T and E2 concentrations across different demographic groups of female humpback whales, and we described some of the first evidence of the endocrine patterns of estrous in live free-ranging baleen whales. This study is fundamental in its methodological approach to a wild species that has a global distribution, with seasonally distinct life histories. This information will assist in monitoring, managing and conserving this population as global ecological changes continue to occur unhindered.

Increasing the reliability of the Bay of Biscay Atlantis model: A sensitivity analysis to parameters perturbations using a Morris screening approach

The Bay of Biscay Atlantis model is expected to become a significant tool for exploring how anthropogenic impacts and environmental variability, in particular fisheries and climate change, could affect the Bay of Biscay ecosystem. Before being used for this purpose, we wanted to identify and evaluate sensitive parameters. Here we present the results of a sensitivity analysis of growth, recruitment, predator-prey availability and mortality parameters for fourteen key or sensitive species/functional groups that make up the food-web of the entire ecosystem, while keeping environmental parameters constant. Specifically, a Morris screening approach has been used to manage the number of parameters and species/functional groups we want to analyse given the computational cost of the simulations. With a small number of simulations, this method can efficiently provide information on main parameter effects and interactions, including identifying non-linear effects. The sensitivity analysis showed that maximum growth rate of large phytoplankton and macrozooplankton, as well as predator-prey availability were the most sensitive parameters. The effects were found to be monotonic or almost-monotonic except predator-prey availability of mesozooplankton, which was non-linear and/or with interactions with other inputs parameters. The responses to the perturbations varied by trophic level. Overall, top predators and fish species/functional groups responded weakly to parameter perturbations, except pelagic shark, baleen whales, toothed cetaceans, horse mackerel, anglerfish, blue whiting, hake, and megrim. Pelagic and benthic invertebrate species/functional groups and primary producers were the most vulnerable to perturbations. The information gained from this sensitivity analysis provided a better understanding of the model structure and highlighted the importance of bottom-up effects.

Giant baleen whales emerged from a cold southern cradle.

Baleen whales (mysticetes) include the largest animals on the Earth. How they achieved such gigantic sizes remains debated, with previous research focusing primarily on when mysticetes became large, rather than where. Here, we describe an edentulous baleen whale fossil (21.12-16.39 mega annum (Ma)) from South Australia. With an estimated body length of 9 m, it is the largest mysticete from the Early Miocene. Analysing body size through time shows that ancient baleen whales from the Southern Hemisphere were larger than their northern counterparts. This pattern seemingly persists for much of the Cenozoic, even though southern specimens contribute only 19% to the global mysticete fossil record. Our findings contrast with previous ideas of a single abrupt shift towards larger size during the Plio-Pleistocene, which we here interpret as a glacially driven Northern Hemisphere phenomenon. Our results highlight the importance of incorporating Southern Hemisphere fossils into macroevolutionary patterns, especially in light of the high productivity of Southern Ocean environments.

Abundance estimates of humpback whales (Megaptera novaeangliae) in Irish coastal waters using mark-recapture and citizen science

Abundance estimates are crucial for implementing effective conservation measures for large marine megafauna – particularly cetaceans. When combined with robust research methodologies, citizen science can provide a very useful tool to monitor large baleen whale populations, especially given their migratory nature, with individuals covering large areas typically exceeding the capacity of single research teams. The Irish Whale and Dolphin Group has been collecting humpback whale photo‐ID data in the inshore waters of Ireland since 1999. The Group curates a catalogue that contained 120 individual humpback whales up to 2022. Most of these data were obtained through citizen science and the catalogue was built following robust methodologies and strict data‐quality protocols. We used this photo‐ID catalogue to derive the first comprehensive abundance estimates for the species in Irish waters using mark‐recapture modelling techniques. We applied two approaches: (1) open population maximum likelihood mark‐recapture models based on the POPAN formulation; (2) a multi‐site mark‐recapture model selection framework based on Bayesian inference. The first method yielded a humpback whale superpopulation size of 154 ± 9 (95% CI = 138–172, CV = 0.06) between 1999–2022, with annual abundance ranging between 2 ± 1 and 77 ± 8 individuals. The second approach provided annual abundance estimates from 3 ± 2 to 76 ± 11 for the same period. This study supports the idea of an increased presence of humpback whales in inshore Irish waters, especially during the last decade. Despite this increase, results also highlight the apparently very small size of the North Atlantic humpback whale subgroup occurring in the inshore waters of Ireland.

A Story of Whales and People: the Portuguese Whaling Monopoly in Brazil (17th and 18th Centuries)

In this work, the history of the whaling operation in Brazil during the 17th and 18th centuries is recovered. The activity was a monopoly of the Iberian (until 1640) and Portuguese crown, from 1614 to 1801, with economic, political, and ecological significance and impact both for the human and non-human protagonists.The abundance of whales and the valorisation of their products worked as drivers - environmental and economic - for the implementation and development of whaling in Bahia, Rio de Janeiro, São Paulo and Santa Catarina. In its duration, this coastal operation followed the ‘Basque-style’ style with the establishment of fixed whaling stations on land and capturing animals very close to shore. For a short period, sperm whales were captured offshore, using techniques characteristic of the ‘American-Style Shore’. The capture focused on coastal baleen whales, from which oil was produced and baleen plates extracted. Contrary to what was previously assumed, these two products were sent to Lisbon in very significant quantities and periodicity, which allows us a better understanding of their importance in the context of the Portuguese colonisation of the Americas and in a framework of ‘wet globalisation’.This marine extraction not only accompanied the processes of appropriation of the territory but was also a stimulus to promote them. It is argued here that whales played a role in providing a source of wealth for the Portuguese empire and in being an integral element in building relationships between people and the ocean.

Analysis of persistent organic pollutants and heavy metals in mysticetes from the United Arab Emirates

Chemical pollution is a major threat that can increase the mortality and lower the reproductive success of cetaceans. In this study we assess, for the first time, the level of contamination of selected priority pollutants consisting of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and heavy metals in whales found stranded in the United Arab Emirates. The samples included five Bryde’s whales (Balaenoptera edeni) and one humpback whale (Megaptera novaeangliae) from the Arabian Gulf and one blue whale (Balaenoptera musculus) from the Gulf of Oman. None of the 18 OCPs tested for were detected. Of the 20 PCB congeners tested for, only one was detected in two (40%) Bryde’s whales.The concentrations of trace elements and heavy metals were lower than reported in baleen whales from the southern hemisphere. PAHs, the predominant pollutants in this study, were detected in the tissues of all examined specimens. The predominance of low molecular weight PAHs over high molecular weight PAHs suggests that PAH exposure may have been primarily from petrogenic sources. The amputation of the tail fluke in one case and bruising of a second whale suggest trauma and marine debris entanglement may have contributed to death in at least two cases. We observed no evidence of marine debris ingestion when such examinations were possible

The first baleen whale marine protected area proposed for Bryde's whales in the Beibu Gulf, China

AbstractThe establishment of marine protected areas (MPAs) for cetaceans is an important strategy to mitigate human disturbance and protect biodiversity. Despite abundant cetacean species, there are only a few MPAs dedicated to cetacean conservation in China, all of which are for inshore dolphins. Bryde's whales, the only nearshore baleen whale population in mainland China, are conflicting with intensive human activities, yet an effective conservation strategy is lacking. This study used species distribution models to analyze distribution patterns and suitable habitats of Bryde's whales in the Beibu Gulf and proposes the first baleen whale MPA in China. Our results showed Bryde's whales have a seasonal distribution pattern in the Beibu Gulf, and that the waters around Weizhou Island and the southeastern coast of Vietnam were their core habitats. The seasonal nighttime light data indicated a negative relationship between the number of ship lights and Bryde's whale sightings and suggest that Bryde's whales might be threatened by fisheries. We proposed an MPA based on the results, suggesting that the waters within 20 km around Weizhou Island should be declared a protected area. Furthermore, we recommend that anthropogenic activities in the waters around Weizhou Island are better managed to reduce negative impacts on marine life.

A macroplastic vulnerability index for marine mammals, seabirds, and sea turtles in Hawai‘i

Plastic pollution is having devastating consequences for marine organisms across the planet. However, the population level effects of macroplastic pollution remain difficult and costly to quantify. As a result, there is a need for alternative approaches to evaluate species risk to plastic pollution and inform management needs. We apply a trait-based framework for macroplastic pollution to develop a relative vulnerability index—informed by three dimensions: likelihood of exposure, species' sensitivity, and population resilience—for marine mammals, seabirds, and sea turtles found in Hawai‘i. This index ranks 63 study species based on their population level vulnerability to macroplastic pollution, with the highest scoring species being the most vulnerable. Our results indicate that ducks, waders, and noddies with large populations were the least vulnerable to macroplastics, while the most vulnerable were the Hawaiian monk seal, sea turtles, baleen whales, and some albatross and petrel species. This index can inform species in need of population monitoring in Hawai'i, and direct other management priorities (e.g., locations for clean-ups or booms). More broadly, this work exemplifies the value of qualitative risk assessment approaches for better understanding the population level effects of macroplastic pollution and showcases how vulnerability indices can be used to inform management priorities.

Echericetus novellus n. gen. n. sp. (Cetacea, Mysticeti, Eomysticetidae), an Oligocene baleen whale from Baja California Sur, Mexico

AbstractAmong the several evolutionary lineages of the baleen whales (Mysticeti), the eomysticetids are an ancient successful family that retain possibly nonfunctional teeth and functional baleen, a transitional stage between toothed and baleen-assisted filter-feeding mysticetes. The patchy fossil record leaves gaps in eomysticetid paleobiology interpretations, but their diversity and widespread geographical distribution can be a relevant proxy to understanding the evolution of crown Mysticeti. Here we describe a new baleen whale, Echericetus novellus n. gen. n. sp., from the Oligocene of Mexico (slightly older than 27.95 million years ago). This new taxon has morphological features that show its affinity to Eomysticetidae, such as the intertemporal region longer than wide, the elongate and oval temporal fossa, and a well-developed and lobate coronoid process of the mandible. Similarly, our cladistic analyses confirm the inclusion of Echericetus in the Eomysticetidae. Echericetus reinforces our notion of the eomysticetid diversity and disparity. Geographically, the existence of Echericetus from Mexico also indicates that eomysticetid inhabited subtropical regions in the Northern Hemisphere. Last, our discovery of a new eomysticetid from the Oligocene of Mexico provides new insights into the distribution patterns and habitat use of Eomysticetidae, essential to further explain the demise of this transitional lineage between toothed and baleen-bearing whales.UUID: http://zoobank.org/00cfc802-e2da-465c-9bb6-59347be00164

Differences in the Diet of Reproductively Isolated Ecotypes of Killer Whales (<i>Orcinus orca</i> Linnaeus, 1758) in the Seas of the Russian Far East

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

Life History Parameters to Inform Pattern of Prenatal Investment in Marine Mammals

Marine mammals are a diverse group of aquatic animals that exhibit wide variation in body size, living conditions, breeding habitat, social behaviour and phylogeny. Although case studies about prenatal investment in cetaceans and pinnipeds have been investigated, comparative studies across different marine mammal taxonomic groups have not yet been conducted systematically. Here, six life history parameters from 75 marine mammal species were collected based on a meta-analysis of the existing literature, and prenatal investment patterns for different taxonomic groups were explored using an unsupervised artificial neural network of a self-organizing map (SOM). Most marine mammal species can be clearly divided into two clusters of small-bodied taxa (small-bodied toothed whales, pinnipeds) and large-bodied taxa (baleen whales, sperm whales and beaked whales, large-bodied toothed whales) based on their distribution within SOM feature maps. Gestation periods and breeding intervals are significantly shorter in pinnipeds than in small-bodied toothed dolphins despite being similar in body size, indicating their adaption to birthing and nursing on land or ice floes. Specific deep-dive feeding behaviour seems to have no impact on the prenatal investment of beaked whales and sperm whales, as these species exhibit a similar capital breeding strategy to baleen whales. Medium-bodied sirenians adopt an intermediate strategy between small-bodied and large-bodied toothed whales, suggesting their prenatal investment strategy is not affected by herbivorous habits. Overall, our results support the body-size hypothesis and breeding-substrate hypothesis and indicate that prenatal investment strategies of marine mammals are possibly not influenced by feeding habits or social behaviour. We suggest that effective conservation measures for small-bodied toothed whales and pinnipeds should prioritize the protection of habitats and minimize human disturbance, whereas conservation measures for large-bodied whales and beaked whales should focus on strategies to prevent substantial declines in population size.

Song Notes and Patterns of the Mediterranean Fin Whale (Balaenoptera physalus) in the Ionian Sea

The Mediterranean fin whale emits two types of 20-Hz calls, known as “classic” and “backbeat”, that can be produced in irregular series or in patterned sequences called songs. The analysis of songs is recognized as a meaningful approach to study baleen whales and can be used to investigate populations’ identities. Mediterranean fin whale songs have been studied previously, but only in the western Mediterranean Sea. This work describes the structure of the songs recorded in the Ionian Sea. The inter-note intervals and the alternation of 20-Hz note types were considered to assess the occurrence of recurring patterns. Differences between patterned songs and irregular sequences were also investigated. Acoustic data were sampled continuously for about 10 months by the cabled observatory NEMO-SN1, deployed at 2100 m depth, 25 km offshore Catania; 28 call sequences were isolated and 10 of these were classified as either patterned songs or irregular sequences. Significant differences were observed in the spectral features of classic notes between songs and irregulars; four-note patterns were found repeatedly over different months, indicating a regular structure in detected songs. This work establishes a reference to interpret Mediterranean fin whale songs, and to assess the acoustic behavior of the population.

Overview of Balaenoptera whales strandings in Southern Brazil from 1993 to 2018

The ecology and distribution of most baleen whales are poorly known in Brazilian waters, despite the history of whaling and the recent increase in the research effort. Although stranding data presents some caveats, it is useful to understand patterns of distribution and occurrence and to detect population trends. In this scenario, data from 25 years of a monitoring marine mammal stranding program were used to evaluate the composition and spatial-temporal patterns of Balaenoptera whales in southern Brazil. A stretch of 270 km on the coast of Rio Grande do Sul State (from 29°20’S to 31°21’S) was surveyed year-round between 1993 and 2018. Whales were identified, measured and sex determined whenever possible. Molecular identification through mtDNA analysis was obtained for 22 individuals and confirmed field identification in 17 cases. Forty-eight whales of four species were recorded: common minke whale B. acutorostrata n = 27, Antarctic minke whale B. bonaerensis n = 1, Bryde’s whale B. brydei n = 13, fin whale B. physalus n = 1. In addition, six whales were not identified at species level due to advanced decomposition. The larger number of strandings of common minke and Bryde’s whales may be related to their greater abundance and/or more coastal distribution. Both species were recorded year-round, but strandings of common minke and Bryde’s whales occurred mostly during winter/spring (77.77%) and spring/summer (66.66%), respectively. Although Bryde’s whales appear to remain in southern Brazilian waters during the entire year, the results suggest the existence of seasonal inshore-offshore movements. Moreover, the greater number of strandings of juveniles of common minke whales compared to adults (ratio 1.86:1) and their occurrence in different seasons suggest that some immature individuals may not leave this region, as previously pointed out by other studies. This long-term survey brings new evidence of the importance of this region in the Southwestern Atlantic Ocean for some Balaenoptera species.

Simulating impacts of fishing toothfish on the pelagic community in the Cooperation Sea, Southern Ocean

There is increasing attention to the use of Antarctic toothfish (Dissostichus mawsoni) and Patagonian toothfish (Dissostichus eleginoides). Understanding the responses of toothfish and other species to fishing activities favors the sustainable use of natural resources. We developed an end-to-end model OSMOSE-CooperationSea to simulate the food web dynamics in the Cooperation Sea and evaluate the impact of toothfish fishery. Fishes and cephalopods played important roles in the energy pathways from krill species and other zooplankton species to toothfish and Weddell seal (Leptonychotes weddellii) whose trophic levels were higher than 5.0. Adélie penguin (Pygoscelis adéliae), Crabeater seal (Lobodon carcinophaga), and Baleen whales were strongly krill-reliant. The spawning stock of toothfish decreased more quickly than the recruitments with increasing fishing pressure. Fishing impacts on the recruitments of toothfish were hysteretic due to the fishing selectivity. The model considered an ontogenetic diet shift of toothfish that mesopelagic fish was influential to toothfish juveniles. The overexploitation of toothfish stock might result in a trophic cascade that mesopelagic fish biomass increased and krill biomass declined. Adélie penguin, Crabeater seal, and Baleen whales preyed on more small fishes in response to the decline of krill biomass. Considering the impacts of changes in Antarctic krill availability, the biomass of Adélie penguin, Crabeater seal, and Baleen whales declined with a heavy toothfish fishery. The study highlights the importance of precautionary and ecosystem-based management to toothfish fishery.

Structured-Light 3D Scanning as a Tool for Creating a Digital Collection of Modern and Fossil Cetacean Skeletons (Natural History Museum, University of Pisa)

The Natural History Museum of the University of Pisa hosts one of the most important osteological collections of cetaceans all over Europe, as well as a conspicuous paleontological collection, including several holotypes of Archaeoceti (archaic whales), Mysticeti (baleen whales), and Odontoceti (toothed whales). In order to valorize these collections, we used 3D technologies to digitize the most relevant specimens, create an online archive, and make the resulting models accessible and shareable with the broadest audience possible through social media profiles and internet browsers. Tens of specimens were surface-scanned using a structured-light scanner, and the resulting 3D models were processed for post-production through the 3D software Blender whenever necessary. All the 3D scans were then gathered in the online repository Sketchfab, which was chosen for its user-friendly interface and common usage among museum institutions. The result is a web page that hosts 35 surface scans of extant and extinct cetacean specimens. This Sketchfab account was linked to the social media (Facebook and Instagram) profiles of the MSNUP to increase the visibility of the museum and promote the dissemination of its outstanding collections of modern and fossil cetaceans. The preliminary results of such an effort are encouraging in terms of views and online interactions. Hopefully, this effort of digitization and online archiving will soon extend to other vertebrate collections.

Ancestry testing of "Old Tom," a killer whale central to mutualistic interactions with human whalers.

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