Content uploaded by Andrew Scullion
Author content
All content in this area was uploaded by Andrew Scullion on Sep 07, 2021
Content may be subject to copyright.
A preview of the PDF is not available
Scottish Killer Whale Photo Identification Catalogue 2021
Abstract
Scottish Killer Whale Photo Identification Catalogue 2021
... These killer whales were photo-identified as the "27s group" through photo-identification to known individuals within a curated catalogue (Scullion et al., 2021). The group was comprised of two adult males (ID #72 and #34), two adult females (ID #27 "Vaila" and ID #73), one female/subadult male (ID #152), and two juveniles or calves (ID #150 [born 2015(ID #150 [born or 2016 and #153 [calf of ID #73, born 2019]; Scullion et al., 2021). ...
... These killer whales were photo-identified as the "27s group" through photo-identification to known individuals within a curated catalogue (Scullion et al., 2021). The group was comprised of two adult males (ID #72 and #34), two adult females (ID #27 "Vaila" and ID #73), one female/subadult male (ID #152), and two juveniles or calves (ID #150 [born 2015(ID #150 [born or 2016 and #153 [calf of ID #73, born 2019]; Scullion et al., 2021). This group regularly moves between the Northern Isles of the UK and more northerly waters (i.e., Faroe Islands, Iceland) and has been observed previously hunting harbour porpoise in Shetland waters (N. ...
... Shucksmith, unpub. data, 2019) and in Eyjafjörður, North Iceland (Scullion et al., 2021). ...
The rapid emergence of new marine developments (e.g., marine renewables, port infrastructure) alongside the substantial growth of existing industries has ultimately resulted in an unprecedented increase in anthropogenic structures within the marine environment over the previous century. Knowledge of whether marine species interact with, avoid, or accommodate and adapt to such structures is essential to ensure that further development of marine environments do not compromise conservation objectives of marine species. This article documents one such interaction. Herein, we describe the observation of a harbour seal (Phoca vitulina) seeking refuge from a group of foraging killer whales (Orcinus orca) within a blue (aka common) mussel (Mytilus edulis) farm. Aerial video footage (38 min 27 s) was collected using an unmanned aerial system during an encounter at an aquaculture site in Gulberwick Bay, Shetland, UK. Analysis of the footage showed the killer whale group spent 73.7% of the total encounter time exhibiting predatory associated behaviours and that they were observed interacting with the mussel farm infrastructure only during “predation activity” for a total of 26 min 52 s (72.8%). The harbour seal interacted with the mussel farm infrastructure during re- and proactive anti-predator behaviour and when exhibiting fatigue for 27 min 59 s, 94.4% of the total time the seal was observed. It is clear that both marine and terrestrial predator–prey interactions are increasingly occurring in settings that are in some way defined by the Anthropocene. The implications of this are discussed, including potential entanglement risk and human-altered “landscapes of fear.” As comprehension of the potential effects of human-altered risk grows, such knowledge should be taken into consideration prior to further modification of marine habitats.
... Unfortunately, the image quality from 1977 precludes a photo-identification match with absolute certainty. Assuming the West Coast community had the same composition in the 1970s as at the start of the 2000s of 10 known animals, 5 of which were males, then W05 is the most likely match because W01 and W04's dorsal fins had distinctive nicks, W02 had a bent fin, W08 had a straight dorsal fin trailing edge (Scullion et al. 2021, HWDT 2023). However, it is possible that this is an undocumented older male belonging to the West Coast Community in the 1970s, with a similar fin shape to W05 but that was never known in the later years, when sightings of this community were more frequently reported with photographic records. ...
... Within Icelandic waters, almost half of individuals sighted more than once followed herring year-round (Marchon et al. 2024;Samarra et al. 2017a). A subset of Icelandic herring-associated killer whales seasonally migrates to Scotland to feed on higher trophic level prey (Samarra and Foote 2015;Samarra et al. 2017b;Scullion et al. 2021). Others are only seen in either herring overwintering or spawning grounds, with their complete movement patterns yet to be discovered (Marchon et al. 2024;Samarra et al. 2017aSamarra et al. , 2017b. ...
Metapopulation dynamics can be shaped by foraging ecology, and thus be sensitive to shifts in prey availability. Genotyping 204 North Atlantic killer whales at 1346 loci, we investigated whether spatio-temporal population structuring is linked to prey type and distribution. Using population-based methods (reflecting evolutionary means), we report a widespread metapopulation connected across ecological groups based upon nuclear genome SNPs, yet spatial structuring based upon mitogenome haplotypes. These contrasting patterns of markers with maternal and biparental inheritance are consistent with matrilineal site fidelity and philopatry, and male-mediated gene flow among demes. Connectivity between fish-eating and ‘mixed-diet’ (eating both fish and mammal prey) killer whales, marks a deviation within a species renowned for its marked structure associated with ecology. However, relatedness estimates suggest distinct spatial clusters, and heterogeneity in recent gene flow between them. The contrasting patterns between inference of structure and inference of relatedness suggest that gene flow has been partially restricted over the past two to three generations (50–70 years). This coincides with the collapse of North Atlantic herring stocks in the late 1960s and the subsequent cessation of their seasonal connectivity. Statistically significant association between diet types and assignment of Icelandic killer whales to relatedness-based clusters indicated limited gene flow was maintained through Icelandic ‘mixed-diet’ whales when herring-mediated connectivity was diminished. Thus, conservation of dietary variation within this metapopulation is critical to ensure genetic health. Our study highlights the role of resource dynamics and foraging ecology in shaping population structure and emphasises the need for transnational management of this widespread migratory species and its prey.
... located in the North-East Atlantic: Greenland(Nicolas et al., 2021), Iceland(Mruzsczok, 2022), Norway(Jourdain & Karoliussen, 2021), Scotland(Scullion et al., 2021), Strait of Gibraltar(Esteban 2023; Moreno- Godoy, unpublished data), and Portugal (Cape Cruiser Sagres, personal communication,3 Moreno-Godoy, unpublished data). Whale watching companies without a formal catalog shared their photographs with One ocean to facilitate the photo-ID process: Azores Islands (Futurismo Azores, personal communication 4 ), Canaries Islands (Tenerife Dolphin, personal communication 5 ), and Portugal (SeaLife Dolphin Watching Lagos, personal communication, 6 Ocean Vibes Algarve, personal communication 7 ). ...
Documenting species occurrence and distribution patterns is fundamental for effective conservation strategies, particularly for endangered species facing various threats. Killer whales ( Orcinus orca ) are distributed worldwide, yet some populations, such as the critically endangered Strait of Gibraltar subpopulation, lack comprehensive distribution data. This study focuses on documenting the occurrence of Strait of Gibraltar killer whales along the French coast of the Bay of Biscay using twenty years (2003–2023) of scientific and citizen science data. Analysis of 34 sightings revealed seasonal patterns, with most sightings occurring between June and November. Also, killer whales are observed more often in the area since 2015. Photo‐identification methods allowed for the identification of 11 individuals, eight of which were recaptured in Spanish and Portuguese catalogs, confirming their affiliation with the Strait of Gibraltar subpopulation. Some individuals have been sighted over several years, regularly travelling together, suggesting potential site fidelity to the Bay of Biscay. Overall movement patterns showed associations with Atlantic bluefin tuna distribution. However, disruptive behaviors observed in some individuals highlight conservation challenges. This study provides novel insights into the distribution and movements of a critically endangered killer whale subpopulation, informing future conservation efforts in the region.
... Local volunteers and wildlife enthusiasts can contribute valuable data to improve the understanding of spatial and temporal patterns in local cetacean populations. This is particularly true where sightings can be made close to the shore by well-trained individuals using suitable, standardised equipment (Scullion et al., 2021;Beck et al., 2014). Increasingly, high quality professional digital cameras are widely available to the general public and citizen scientists, facilitating the collection of and contribution to photo-identification catalogues relevant to research projects. ...
There is no current population estimate for Risso’s dolphin ( Grampus griseus ) in Scottish waters and their distribution in the northeast of Scotland and the Northern Isles is poorly documented. Using a combination of citizen science and historical sightings data, photographs of Risso’s dolphins from northeast Scotland and the Northern Isles were gathered to gain an indication of the presence of the species in this region. A review of all available sighting records from as early as 1933 (n = 1,904 records), showed a historical presence of Risso’s dolphins in the study locations, with a notable increase in sightings reports over time and with higher numbers of sightings reported from July-September. Collation of photographs (n = 1,884) taken by members of the public and researchers facilitated the establishment of two photo-identification catalogues for Northeast Scotland and Orkney (n = 112 individuals) and for Shetland (n = 47 individuals) respectively. Mother/calf pairs were recorded between April and November. Repeated recaptures of identifiable animals throughout the study area provided the first evidence of inter/intra-annual site fidelity. The combined datasets demonstrate the potential importance of inshore coastal waters in northeast Scotland, Orkney, and Shetland as critical habitat for Risso’s dolphins. Recommendations are made for ongoing monitoring studies to inform the protection of Risso’s dolphins in Scottish waters.
... In contrast, two critically small communities occur in European waters, one in the UK, the West Coast Community numbering just 8 individuals (HWDT 2018), and another in the Strait of Gibraltar, South Spain, numbering 39 individuals (Esteban et al. 2016a). In Shetland, approximately 150 killer whales occurring in nearshore waters have been identified (Scullion et al. 2021). Several tens of whales are observed interacting with mackerel fisheries off Northern Ireland and Scotland (Pinfield et al. 2019), while off the West and the East coast of Greenland several tens of whales have been harvested, but there are no abundance estimates for these regions (Jourdain et al. 2019b). ...
Investigating the movements and site fidelity of individuals enhances our understanding of population ecology and structure. Killer whales occur around the coast of Iceland; however, information on the connectivity between different regions is limited to herring grounds, where they are observed frequently. In this study, we used photo-identification data to investigate the movements and site fidelity of whales within (South and West) and outside (Southwest, Northwest, Northeast and East) Icelandic herring grounds. Additionally, we used a 10-year photo-identification dataset in the South to investigate long-term site fidelity patterns to a single location. Of the 440 individuals sighted more than once, nearly half (48%) moved between herring grounds and site fidelity was higher within, compared to outside, herring grounds. Outside herring grounds, individuals showed: more movement from Southwest to West compare to South, indicating this region is not exclusively a passage between herring grounds; low site fidelity to the Northeast with fewer photographic matches to other regions, suggesting individuals found here may be part of an offshore population that occasionally visits the area; and low proportion of matches to other regions in the Northwest and East, although small sample sizes precluded firm conclusions. Finally, long-term residency of killer whales in the South showed dynamic patterns, likely caused by prey availability and/or environmental changes. This study elucidates the complexities of killer whale occurrence and connectivity within the North Atlantic and suggests population structure that should be further investigated for appropriate regional conservation assessments.
In this short commented identification catalogue, we present information on individual orcas migrating between Iceland and Scotland, emphasizing on recent sightings data from both Iceland and Scotland, as well as group affiliation. ID matches were possible only with the great help of dedicated whale watchers, wildlife guides, and conservationists, who were looking out for these specific orcas along the Scottish shoreline. Once good quality identification images were available from the Scottish mainland, Orkney, Shetland, and the Hebrides, we could then compare these photographs to our pictures taken in West Iceland along the Snæfellsnes Peninsula through vessel-based data collection from 2014 to 2018. In 2017 and 2018 alone, this yielded the discovery of 8 more individuals migrating between Scotland and Iceland.
The article reports on the killer whale, known as Orcinus orca and its occurrence in the Moray Firth, Northeast Scotland. Topics discussed include the incidental sightings of this species, its behavioural observations, and photo-identification. Also being discussed are the white-beaked dolphins called Lagenorhynchus albirostris, and annual pupping season of the common seal called Phoca vitulina.
Predators specialising on migratory prey that frequently change migration route face the challenge of finding prey with an unpredictable distribution. Here, we used photo-identification data to investigate whether killer whales observed in herring overwintering and spawning grounds off Iceland follow herring year-round, as previously proposed, and have the ability to adapt to long-term changes in herring distribution. Of 327 identified whales seen more than once, 45% were seen in both grounds, and were thus presumed herring-specialists, likely following herring year-round, while others were only seen on one of the grounds, possibly following herring to unsampled grounds or moving to other locations and exploiting different prey. High seasonal site fidelity to herring grounds, long-term site fidelity to herring spawning grounds, and matches of individual whales between past and recently occupied herring overwintering grounds showed an ability to adapt to long-term changes in prey distribution as well as diversity of movement patterns which are maintained over time, likely as socially-learnt traditions. Such population structuring shows that the movement patterns and foraging ecology of herring-eating killer whales are more complex than previously assumed and must be taken into account in future population assessments. Identifying the factors driving these differences in movements and resource use will be relevant towards our understanding of how prey predictability may drive specialization in this and other top predator species.
Organochlorine (OC) pesticides and the more persistent polychlorinated biphenyls (PCBs) have well established dose-dependent toxicities to birds, fish and mammals in experimental studies, but the actual impact of OC pollutants on European marine top predators remains unknown. Here we show that several cetacean species have very high mean blubber PCB concentrations likely to cause population declines and suppress population recovery. In a large pan-European meta-analysis of stranded (n = 929) or biopsied (n = 152) cetaceans, three out of four species:- striped dolphins (SDs), bottlenose dolphins (BNDs) and killer whales (KWs) had mean PCB levels that markedly exceeded all known marine mammal PCB toxicity thresholds. Some locations (e.g. western Mediterranean Sea, south-west Iberian Peninsula) are global PCB “hotspots” for marine mammals. Blubber PCB concentrations initially declined following a mid-1980s EU ban, but have since stabilised in UK harbour porpoises and SDs in the western Mediterranean Sea. Some small or declining populations of BNDs and KWs in the NE Atlantic were associated with low recruitment, consistent with PCB-induced reproductive toxicity. Despite regulations and mitigation measures to reduce PCB pollution, their biomagnification in marine food webs continues to cause severe impacts among cetacean top predators in European seas.
PCB—still a problem
Until they were recognized as highly toxic and carcinogenic, polychlorinated biphenyls (PCBs) were once used widely. Their production was banned in the United States in 1978, though they are still produced globally and persist in the environment. Persistent organic compounds, like PCBs, magnify across trophic levels, and thus apex predators are particularly susceptible to their ill effects. Desforges et al. looked at the continuing impact of PCBs on one of the largest marine predators, the killer whale. Using globally available data, the authors found high concentrations of PCBs within killer whale tissues. These are likely to precipitate declines across killer whale populations, particularly those that feed at high trophic levels and are the closest to industrialized areas.
Science , this issue p. 1373
Non-social factors can influence animal social structure. In killer whales (Orcinus orca), fish-versus mammal-eating ecological differences are regarded as key ecological drivers of their multilevel society, including group size, but the potential importance of specific target prey remains unclear. Here, we investigate the social structure of herring-eating killer whales in Iceland and compare it to the described social structures of primarily salmon- A nd seal-eating populations in the Northeast Pacific, which form stable coherent basic units nested within a hierarchical multilevel society. Using 29 023 photographs collected over 6 years, we examined the association patterns of 198 individuals combining clustering, social network structure, and temporal patterns of association analysis. The Icelandic population had largely weak but non-random associations, which were not completely assorted by known ranging patterns. A fission-fusion dynamic of constant and temporary associations was observed but this was not due to permanent units joining. The population-level society was significantly structured but not in a clear hierarchical tier system. Social clusters were highly diverse in complexity and there were indications of subsclusters. There was no indication of dispersal nor strong sex differences in associations. These results indicate that the Icelandic herring-eating killer whale population has a multilevel social structure without clear hierarchical tiers or nested coherent social units, different from other populations of killer whales. We suggest that local ecological context, such as the characteristics of the specific target prey (e.g., predictability, biomass, and density) and subsequent foraging strategies may strongly influence killer whale social association patterns.
About 40 percent of a sample of Baltic ringed seal females of reproductive age showed pathological changes of the uterus. The uterine horns were closed by stenosis and occlusions, preventing any passage from the ovary out through the horn. This explains their low reproduction rate. Animals showing these changes had significantly higher levels of DDT and PCB substances than normal, pregnant females. These pathological changes were also found among grey seal from the Baltic area, as well as among harbor seal from the Swedish west coast. It is strongly indicated that PCB is responsible for the reproductive failure of seals in the Baltic area. A significant positive correlation between DDT and PCB levels and age was found in the males but not in the females. The levels of DDT and PCB substances were somewhat lower in fetuses, than in their mothers.