Killer Whale Ecotypes Research Articles

Auto machine learning tools to distinguish between two killer whale ecotypes

Auto machine learning tools to distinguish between two killer whale ecotypes

The Racialization of Killer Whales: An Application of Gene-Culture Coevolutionary Theory

Abstract An expanding body of research aims to identify culture in cetaceans, often positing killer whales as an exemplar species. To this end, gene-culture coevolutionary theory provides a conceptual language with which whales are discussed in raciological terms. It renders killer whale ecotypes as discrete cultures that are intrinsically xenophobic and evolutionarily divergent. Such research on whale culture intends to substantiate theories of divergent natural selection between human cultures as well. This effort furthers the essentialism, simultaneously biological and cultural, that has long impelled colonial technoscientific projects of racial typologization. The exchange between the raciologies of humans and killer whales is facilitated by the infrahumanizing frameworks of gene-culture coevolutionary theory that locate whale populations alongside indigenous peoples on a spectrum of cultural simplicity and complexity. At this convergence of the animal and the human, gene-culture coevolutionary theory posits indigenous peoples and killer whales as evidence for social Darwinist theories that dehistoricize and naturalize intercultural conflict and ethnicization. The extension of raciology beyond the human species signals an urgent need to decolonize the biological sciences.

Revised taxonomy of eastern North Pacific killer whales (Orcinus orca): Bigg's and resident ecotypes deserve species status.

Killer whales (Orcinus orca) are currently recognized as a single ecologically and morphologically diverse, globally distributed species. Multiple morphotypes or ecotypes have been described, often associated with feeding specialization, and several studies have suggested taxonomic revision to include multiple subspecies or species in the genus. We review the ecological, morphological and genetic data for the well-studied 'resident' and Bigg's (aka 'transient') ecotypes in the eastern North Pacific and use quantitative taxonomic guidelines and standards to determine whether the taxonomic status of these killer whale ecotypes should be revised. Our review and new analyses indicate that species-level status is justified in both cases, and we conclude that eastern North Pacific Bigg's killer whales should be recognized as Orcinus rectipinnus (Cope in Scammon, 1869) and resident killer whales should be recognized as Orcinus ater (Cope in Scammon, 1869).

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

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

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.

Evidence of Type A-Like Killer Whales (Orcinus orca) Predating on Marine Mammals Along the Atacama Desert Coast, Chile

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

Echolocation click discrimination for three killer whale ecotypes in the Northeastern Pacific.

Three killer whale ecotypes are found in the Northeastern Pacific: residents, transients, and offshores. These ecotypes can be discriminated in passive acoustic data based on distinct pulsed call repertoires. Killer whale acoustic encounters for which ecotypes were assigned based on pulsed call matching were used to characterize the ecotype-specific echolocation clicks. Recordings were made using seafloor-mounted sensors at shallow (∼120 m) and deep (∼1400 m) monitoring locations off the coast of Washington state. All ecotypes' echolocation clicks were characterized by energy peaks between 12 and 19 kHz, however, resident clicks featured sub peaks at 13.7 and 18.8 kHz, while offshore clicks had a single peak at 14.3 kHz. Transient clicks were rare and were characterized by lower peak frequencies (12.8 kHz). Modal inter-click intervals (ICIs) were consistent but indistinguishable for resident and offshore killer whale encounters at the shallow site (0.21-0.22 s). Offshore ICIs were longer and more variable at the deep site, and no modal ICI was apparent for the transient ecotype. Resident and offshore killer whale ecotype may be identified and distinguished in large passive acoustic datasets based on properties of their echolocation clicks, however, transient echolocation may be unsuitable in isolation as a cue for monitoring applications.

Passive acoustic monitoring reveals feeding attempts at close range from soaking demersal longlines by two killer whale ecotypes

AbstractOdontocetes depredating fish caught on longlines is a serious socio‐economic and conservation issue. A good understanding of the underwater depredation behavior by odontocetes is therefore required. Historically, depredation on demersal longlines has always been assumed to occur during the hauling phase. In this study, we have focused on the depredation behavior of two ecotypes of killer whales, Orcinus orca, (Crozet and Type D) from demersal longlines around the Crozet Archipelago (Southern Indian Ocean) using passive acoustic monitoring. We assessed 74 hr of killer whale acoustic presence out of 1,233 hr of recordings. Data were obtained from 29 hydrophone deployments from five fishing vessels between February and March 2018. We monitored killer whale buzzing activity (i.e., echolocation signals) as a proxy for feeding attempts around soaking longlines. These recordings revealed that the two ecotypes were feeding at close range from soaking longlines, even when fishing vessels were not present. Our results suggest that both killer whale ecotypes are likely to depredate soaking longlines, which would imply an underestimation of their depredation rates. The implication of underestimating depredation rates is inaccurate accounting for fish mortality in fisheries' stock assessments.

A long postreproductive life span is a shared trait among genetically distinct killer whale populations.

The extended female postreproductive life span found in humans and some toothed whales remains an evolutionary puzzle. Theory predicts demographic patterns resulting in increased female relatedness with age (kinship dynamics) can select for a prolonged postreproductive life span due to the combined costs of intergenerational reproductive conflict and benefits of late‐life helping. Here, we test this prediction using >40 years of longitudinal demographic data from the sympatric yet genetically distinct killer whale ecotypes: resident and Bigg's killer whales. The female relatedness with age is predicted to increase in both ecotypes, but with a less steep increase in Bigg's due to their different social structure. Here, we show that there is a significant postreproductive life span in both ecotypes with >30% of adult female years being lived as postreproductive, supporting the general prediction that an increase in local relatedness with age predisposes the evolution of a postreproductive life span. Differences in the magnitude of kinship dynamics however did not influence the timing or duration of the postreproductive life span with females in both ecotypes terminating reproduction before their mid‐40s followed by an expected postreproductive period of about 20 years. Our results highlight the important role of kinship dynamics in the evolution of a long postreproductive life span in long‐lived mammals, while further implying that the timing of menopause may be a robust trait that is persistent despite substantial variation in demographic patterns among populations.

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

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.

Size and body condition of sympatric killer whale ecotypes around the Antarctic Peninsula

Killer whales Orcinus orca are apex predators, and their health can indicate trophic dynamics in ecosystems that support them. We used aerial photogrammetry to estimate body lengths, to better understand size differences and food requirements, and widths, to infer current nutritional condition, of killer whales in the rapidly warming waters around the Antarctic Peninsula. A remotely controlled hexacopter drone was used to collect aerial images of 242 killer whales of 3 sympatric ecotypes (Type A, n = 34; Type B1, n = 19; and Type B2, n = 189) in the austral summers between 2015/2016 and 2018/2019. Total length (TL) varied between ecotypes, with B2s being diminutive in size, indicating large differences in energy requirements. The mean length for adult females ranged from 5.82 m (B2s) to 6.93 m (B1s), and the mean for adult males ranged from 6.44 m (B2s) to 7.80 m (As). We also found significant differences in head width (HW, proxy for body condition), with B2s being significantly leaner. Although this variation may reflect natural shape differences, we also estimated divergent regression lines of HW~TL indicating that this difference was greater at larger body sizes, with some anomalously thin adult female B2s. We suggest that these dissimilarities may indicate a density-dependent response, with leaner body condition in adults with higher energetic requirements, as the abundance of B2s is almost an order of magnitude greater than that of B1s and As. We hypothesize that food limitation resulted from a decline in carrying capacity during recent reductions in sea ice and warmer ocean temperatures.

Indication that the behavioural responses of humpback whales to killer whale sounds are influenced by trophic relationships

Eavesdropping, the detection of communication signals by unintended receivers, can be beneficial in predator-prey interactions, competition, and cooperation. The cosmopolitan killer whaleOrcinus orcahas diverged into several ecotypes which exhibit specialised diets and different vocal behaviours. These ecotypes have diverse ecological relationships with other marine mammal species, and sound could be a reliable sensory modality for eavesdroppers to discriminate between ecotypes and thereby respond adaptively. Here, we tested whether humpback whalesMegaptera novaeangliaein the Northeast Atlantic responded differently to playback of the sounds of 2 killer whale ecotypes, Northeast Atlantic herring-feeding killer whales representing food competitors and Northeast Pacific mammal-eating killer whales simulating potential predators. We used animal-borne tags and surface visual observations to monitor the behaviour of humpback whales throughout the playback experiments. Humpback whales clearly approached the source of herring-feeding killer whale sounds (5 of 6 cases), suggesting a ‘dinner-bell’ attraction effect. Responses to mammal-eating killer whale sounds varied with the context of presentation: playback elicited strong avoidance responses by humpback whales in offshore waters during summer (7 of 8 cases), whereas the whales either approached (2 of 4 cases) or avoided (2 of 4 cases) the sound source in inshore waters during winter. These results indicate that humpback whales may be able to functionally discriminate between the sounds of different killer whale ecotypes. Acoustic discrimination of heterospecific sounds may be widespread among marine mammals, suggesting that marine mammals could rely on eavesdropping as a primary source of information to make decisions during heterospecific encounters.

Compliance of small vessels to minimum distance regulations for humpback and killer whales in the Salish Sea

To support optimal monitoring and enforcement investment, management aimed at minimizing disturbance to wildlife requires an understanding of how regulatory compliance might vary spatially as well as across species and human-user groups. In the Salish Sea, humpback whales (Megaptera novaeangliae) and two ecotypes (southern resident and Bigg's) of killer whales (Orcinus orca) now interact with a large and growing number of small commercial and recreational vessels that partake in whale watching. Those vessels often approach close to cetaceans and thus pose risk via collision, marine noise and pollution, exposure to which may result in disturbance, injury and death. The primary management tool for mitigating impacts is minimum distance regulations. Compliance, however, is poorly understood. We examined commercial and recreational small vessel compliance with viewing distances across two seasons (June–September 2018 and 2019) in over ≈404 h of on-water observation. Overall vessel compliance was nearly 80%, but several distinct patterns emerged. Recreational boats were significantly more likely to violate distance regulations and boaters were more likely to be non-compliant around killer whales. Compliance did not vary with day of week or time of day. Spatially, non-compliance was concentrated in waters closer to coastal communities. Collectively, these patterns suggest that optimal enforcement could be targeted to identify areas of high non-compliance, especially for killer whales, with effort spread across days and times. Finally, we discuss how investments in education could target recreational boaters at a time when multiple and interacting stressors are accumulating in the Salish Sea.

Ecotype and geographical variation in carbon and nitrogen stable isotope values in western North Pacific killer whales (Orcinus orca)

AbstractKiller whales are top predators in marine trophic chains, and therefore their feeding preferences can substantially affect the abundance of species on the lower trophic levels. Killer whales are known to feed on many different types of prey from small fish to large whales, but a given killer whale population usually focuses on a specific type of prey. Stable isotope analysis is widely used to study whale diets, because direct observations are often impossible. Killer whale feeding habits in the western North Pacific are poorly studied, and the large‐scale stable isotope analysis provides a unique opportunity to gain insights into the trophic links of this top predator. In this study, we compare the δ13C and δ15N stable isotope values from killer whale skin samples obtained in different areas of the western North Pacific from fish‐eating (R‐type) and mammal‐eating (T‐type) killer whale ecotypes. The effect of ecotype was highly significant: both carbon and nitrogen stable isotope values were lower in R‐type whales than in T‐type whales. The geographical variation also affected killer whale stable isotope values due to both the differences in killer whale diet and the variation in baseline stable isotope values across the study areas.

Amino acid δ15N underestimation of cetacean trophic positions highlights limited understanding of isotopic fractionation in higher marine consumers.

Compound‐specific stable isotope analysis (CSIA) of amino acids (AAs) has been rapidly incorporated in ecological studies to resolve consumer trophic position (TP). Differential 15N fractionation of “trophic” AAs, which undergo trophic 15N enrichment, and “source” AAs, which undergo minimal trophic 15N enrichment and serve as a proxy for primary producer δ15N values, allows for internal calibration of TP. Recent studies, however, have shown the difference between source and trophic AA δ15N values in higher marine consumers is less than predicted from empirical studies of invertebrates and fish. To evaluate CSIA‐AA for estimating TP of cetaceans, we compared source and trophic AA δ15N values of multiple tissues (skin, baleen, and dentine collagen) from five species representing a range of TPs: bowhead whales, beluga whales, short‐beaked common dolphins, sperm whales, and fish‐eating (FE) and marine mammal‐eating (MME) killer whale ecotypes. TP estimates (TPCSIA) using several empirically derived equations and trophic discrimination factors (TDFs) were 1–2.5 trophic steps lower than stomach content‐derived estimates (TPSC) for all species. Although TPCSIA estimates using dual TDF equations were in better agreement with TPSC estimates, our data do not support the application of universal or currently available dual TDFs to estimate cetacean TPs. Discrepancies were not simply due to inaccurate TDFs, however, because the difference between consumer glutamic acid/glutamine (Glx) and phenylalanine (Phe) δ15N values (δ15NGlx‐Phe) did not follow expected TP order. In contrast to pioneering studies on invertebrates and fish, our data suggest trophic 15N enrichment of Phe is not negligible and should be examined among the potential mechanisms driving “compressed” and variable δ15NGlx‐Phe values at high TPs. We emphasize the need for controlled diet studies to understand mechanisms driving AA‐specific isotopic fractionation before widespread application of CSIA‐AA in ecological studies of cetaceans and other marine consumers.

Cold call: the acoustic repertoire of Ross Sea killer whales (Orcinus orca, Type C) in McMurdo Sound, Antarctica.

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.

Call discrimination for an unknown pod of killer whales (Orcinus orca) in the Eastern Canadian Arctic

Killer whales produce pulsed calls, which are used for communication. Calls are highly stereotyped, and repertoires are unique to individual pods. Discrimination amongst these calls and comparison of call repertoires between pods can help determine population structure in killer whales and can be used to track pod movements. Calls were detected in underwater acoustic recordings from August to September 2017 in the waters near the community of Pond Inlet, Nunavut, Canada. Eight stereotypic call types were identified using whistle contour extraction and network analysis to compare contours. We present a repertoire of killer whale calls recorded. The potential for increased killer whale presence and magnitude of predation on narwhals is a source of concern for management of the population and by Inuit subsistence hunters who rely on narwhals for food and economic benefit. Describing the acoustic repertoire of killer whales seasonally present in the Canadian Arctic may help identify the stock or pod and determine their seasonal movements. Comparisons of this repertoire with killer whale calls from other Atlantic pods has not yet yielded a match. However, the results presented may provide a basis for future comparisons and aid in identifying killer whale ecotypes making seasonal incursions into Arctic waters.

Evidence for discrimination between feeding sounds of familiar fish and unfamiliar mammal-eating killer whale ecotypes by long-finned pilot whales.

Killer whales (KW) may be predators or competitors of other cetaceans. Since their foraging behavior and acoustics differ among populations ('ecotypes'), we hypothesized that other cetaceans can eavesdrop on KW sounds and adjust their behavior according to the KW ecotype. We performed playback experiments on long-finned pilot whales (Globicephala melas) in Norway using familiar fish-eating KW sounds (fKW) simulating a sympatric population that might compete for foraging areas, unfamiliar mammal-eating KW sounds (mKW) simulating a potential predator threat, and two control sounds. We assessed behavioral responses using animal-borne multi-sensor tags and surface visual observations. Pilot whales barely changed behavior to a broadband noise (CTRL-), whereas they were attracted and exhibited spyhops to fKW, mKW, and to a repeated-tonal upsweep signal (CTRL+). Whales never stopped nor started feeding in response to fKW, whereas they reduced or stopped foraging to mKW and CTRL+. Moreover, pilot whales joined other subgroups in response to fKW and CTRL+, whereas they tightened individual spacing within group and reduced time at surface in response to mKW. Typical active intimidation behavior displayed to fKW might be an antipredator strategy to a known low-risk ecotype or alternatively a way of securing the habitat exploited by a heterospecific sympatric population. Cessation of feeding and more cohesive approach to mKW playbacks might reflect an antipredator behavior towards an unknown KW ecotype of potentially higher risk. We conclude that pilot whales are able to acoustically discriminate between familiar and unfamiliar KW ecotypes, enabling them to adjust their behavior according to the perceived disturbance type.

The summer diet of fish-eating killer whales in the Avacha Gulf of Kamchatka: Are there any preferences?

Dietary specialization has led to the origin of several ecotypes of killer whales (Orcinus orca). Comparing the feeding habits of different populations within an ecotype is valuable for understanding the evolution of foraging strategies. In this study we investigated the diet of fish-eating killer whales in the Northwest Pacific Ocean (Avacha Gulf, Kamchatka) and compared it to the published data on Northeast Pacific fish-eating killer whales. We collected prey fragments (N = 141) after hunting events in the summer seasons of 2011–2016 and determined the species of prey. Killer whales fed mainly on various species of Pacific salmon in Avacha Gulf. Coho salmon (Oncorhynchus kisutch) (56% of samples) and chum salmon (O. keta) (31% of samples) predominated in the diet. The results are comparable to the peculiarities of the fish-eating killer whale diet in the Northeast Pacific where killer whales prefer Chinook salmon (O. tshawytscha) most of the summer but shift toward coho and chum in late summer. Avacha Gulf could be an area where killer whales come to hunt coho similar to Prince William Sound in Alaska where killer whales prefer coho to other salmon species. We found significant differences in the diet between sex-age categories. Females (N = 42) and juveniles (N = 15) were more selective and hunted mainly coho while males (N = 53) hunted chum equally to coho. Like Chinook in British Columbia, coho in Kamchatka has a prolonged spawning period. Coho is the most nutritious after Chinook. Coho’s prolonged abundance and nutritional value probably make it preferable to killer whales especially females.

Large-scale habitat segregation of fish-eating and mammal-eating killer whales (Orcinus orca) in the western North Pacific

Top predators strongly impact the structure of ecosystems through the top-down cascading effects on prey species. Killer whales (Orcinus orca), the top predators in marine ecosystems, are increasing their presence in the Arctic following the ice cover loss. The impact of killer whales on marine ecosystems differs dramatically across ecotypes: ‘resident’ R-type killer whales feed mostly on large fish, while ‘transient’ T-type whales feed mostly on marine mammals. We analyze the differences in geographical distribution of killer whale ecotypes in the western North Pacific in order to predict the potential effects of climate change on their range and the consequential impact on Arctic ecosystems. We show that R-type whales prevail in the coastal waters of eastern Kamchatka, Commander and Kuril Islands and in the central Okhotsk Sea, while T-type whales dominate the coastal waters of Chukotka and the coastal Okhotsk Sea. The most prominent difference between these areas is depth: in the regions where R-type whales prevail, deep waters occur close to shore, while the regions dominated by T-type whales are represented by wide shallows covered with ice in winter. We propose several hypotheses to explain this large-scale segregation, including distribution of prey species and ice cover. Habitat preferences suggest that range expansion in the Arctic induced by climate change will likely involve mostly T-type killer whales and consequently increase the predation pressure on marine mammals to a greater extent than on fish stocks. This should be considered in further studies and prediction models highlighting Arctic marine ecosystems change.