Bowhead Research Articles

Recent abundance of bowhead whales in Isabella Bay, Canada

An aerial survey of the late-summer distribution of bowhead whales, Balaena mysticetus, in Isabella Bay, Nunavut, Canada, was conducted on 19 September 2009. A total of 28 sightings were obtained during 155km of survey effort and >90% of the sightings were detected by both platforms. Corrections were made for whales that were submerged during the passage of the survey plane, resulting in an abundance estimate of 1,105 bowhead whales (95% CI: 532–2,294). No cow-calf pairs were observed confirming earlier observations that east Baffin Island is primarily visited by subadult and adult whales.

Sea ice directs changes in bowhead whale phenology through the Bering Strait

BackgroundClimate change is warming the Arctic faster than the rest of the planet. Shifts in whale migration timing have been linked to climate change in temperate and sub-Arctic regions, and evidence suggests Bering–Chukchi–Beaufort (BCB) bowhead whales (Balaena mysticetus) might be overwintering in the Canadian Beaufort Sea.MethodsWe used an 11-year timeseries (spanning 2009–2021) of BCB bowhead whale presence in the southern Chukchi Sea (inferred from passive acoustic monitoring) to explore relationships between migration timing and sea ice in the Chukchi and Bering Seas.ResultsFall southward migration into the Bering Strait was delayed in years with less mean October Chukchi Sea ice area and earlier in years with greater sea ice area (p = 0.04, r2 = 0.40). Greater mean October–December Bering Sea ice area resulted in longer absences between whales migrating south in the fall and north in the spring (p < 0.01, r2 = 0.85). A stepwise shift after 2012–2013 shows some whales are remaining in southern Chukchi Sea rather than moving through the Bering Strait and into the northwestern Bering Sea for the winter. Spring northward migration into the southern Chukchi Sea was earlier in years with less mean January–March Chukchi Sea ice area and delayed in years with greater sea ice area (p < 0.01, r2 = 0.82).ConclusionsAs sea ice continues to decline, northward spring-time migration could shift earlier or more bowhead whales may overwinter at summer feeding grounds. Changes to bowhead whale migration could increase the overlap with ships and impact Indigenous communities that rely on bowhead whales for nutritional and cultural subsistence.

Resources of commercial cetacean species in the Russian Federation and whaling in 2014–2021.

Data about population state of commercial species of cetaceans in the Russian Federation and whaling volumes for the period 2014–2021 are presented. Large-scale whaling in the Far-Eastern seas has been stopped since mid-1990s, and currently whaling exists as traditional economic activities of local indigenous population, although until 2019 it was used for educational and cultural purposes also. During the period of planned economic activities the hanting for marine mammals was an integral part of Soviet economy. In the early 1990s, as the state holding stopped, hunting for marine mammals operated with traditional methods, and so the volume of hanting and the amount of scientific information both reduced. Based on the current data on the abundance of the Far-Eastern populations of commercial cetacean species (except killer whales and small cetaceans, which whaling ceased entirely) potential number of beluga whales for hunting removal can reach 74 in the Bering and Chukchi Seas, up to 100 in the Sea of Okhotsk, and 150 in the White, Kara and Barents Seas. Whaling the gray and bowhead whales is carried out in accordance with recommendations of the International Whaling Commission (IWC), and there are no plans now to increase existing quotas.

Correction factors account for the availability of bowhead whales exposed to seismic operations in the Beaufort Sea

The accuracy of estimates of cetacean density from line-transect survey data depends in large part on how visible the target species is to the observer. Behavioural data (i.e. surface and dive times) from government- and industry-funded aerial observation programmes (1980–2000) were used to calculate availability correction factors needed to estimate the number of bowhead whales (Balaena mysticetus) from aerial survey sighting data. Correction factors were calculated for bowhead whales exposed and not exposed to seismic operations. Travelling non-calf whales were found to be less likely to be available for detection than other whales, and their availability further declined in the presence of seismic operations. Noncalves were also less available to observers during autumn when exposed to seismic operations than when not exposed, regardless of activity (travelling or otherwise). Such differences in availability appear to reflect behavioural responses to the sound of seismic operations that alters the surfacing and diving patterns of bowhead whales. Localised abundance estimated from aerial surveys may range from 3% to as much as 63% higher in areas ensonified by seismic operations if correction factors are applied to account for differences in availability associated with the presence of seismic operations, compared to abundance estimates derived from assessments that only account for changes in availability of undisturbed whales. These results provide the first empirical estimates of availability for bowhead whales exposed to seismic operations and highlight the implications of not correcting for disturbance-related availability in density assessments in the vicinity of seismic operations.

Age classification of bowhead whales using recursive partitioning

An algorithm was derived for using morphometric data to classify bowhead whales into three age brackets: over 90 years (‘very old’); 60–90 years (‘old’); and under 60 (‘younger’). Recursive partitioning was applied to a subset of the data from post mortem examinations. This subset consisted of whales with higher quality data scores and with either estimated ages or characteristics of very old animals such as: near-maximum body length and baleen length; heavy scarring; and ancient weapons embedded in them. Statistical analysis suggested that for males, body length and peduncle girth provide the most useful information for this age classification. For females, anterior flipper length and body length were the key variables for classifying age. If anterior flipper length is not available for females, then body length, baleen length and peduncle girth may be used to classify age.

Possible signs of recovery of the nearly extirpated Spitsbergen bowhead whales: calves observed in east Greenland

The Spitsbergen population of bowhead whales (Balaena mysticetus) was harvested to near extinction during the whaling era. Here, we show possible signs of recovery of the population by reporting observations of two calves in the Scoresby Sund polynya in East Greenland on 2 and 4 May 2022, and it is the first observation of this kind in this area since the early 1900s.

Revisiting the footprints of climate change in Arctic marine food webs: An assessment of knowledge gained since 2010

In 2011, a first comprehensive assessment of the footprints of climate change on Arctic marine ecosystems (such as altered distribution ranges, abundances, growth and body conditions, behaviours and phenologies, as well as community and regime shifts) was published. Here, we re-assess the climate-driven impacts reported since then, to elucidate to which extent and how observed ecological footprints have changed in the following decade (2011 to 2021). In total, 98 footprints have been described and analysed. Most of those impacts reported in the 2011 assessment are reconfirmed and can, hence, be assumed as continuing trends. In addition, novel footprints (behavioural changes, diet changes, altered competition and pathogen load) are described. As in 2011, most reported footprints are related to changes in distribution ranges, abundances, biomass and production. Range shifts have mostly been observed for fish species, while behavioural changes have mainly been reported for mammals. Primary production has been observed to further increase in Arctic seas. The footprints on pelagic herbivores, particularly the key species Calanus spp., are less clear. In comparison to 2011, more complex, cascading effects of climate change, such as increased bowhead whale body conditions due to increased primary production, have been reported. The observed footprints, and the trends that they indicate, strongly suggest that due to further northward range shifts of sub-Arctic and boreal species Arctic seas are likely to experience increasing species richness in the future. However, a tipping point may be reached, characterized by subsequent biodiversity decline, when Arctic-endemic species will go extinct as ocean warming and/or acidification will exceed their physiological adaptation capacity. Furthermore, as invading boreal species have a competitive advantage due to their wider physiological and trophic range, Arctic species abundances are predicted to decrease. Overall, the future Arctic Ocean will very likely experience increasing numbers and intensities of climate-change footprints.

A note on sightings of bowhead whales in the North Water Polynya, Northern Baffin Bay, May-June, 1998

As part of a multidisciplinary research cruise by icebreaker in the North Water Polynya in northern Baffin Bay, we conducted shipboard surveys of marine mammal distribution and abundance throughout the area from April to July 1998. Fourteen sightings of at least ten individual bowhead whales (Balaena mysticetus) were made during May and June. Five additional large baleen whales, whose identities were not confirmed, were also seen. As well as being an important feeding ground, the polynya may also serve as an overwintering site for bowhead whales of the Davis Strait/Baffin Bay stock.

Acoustic data from the spring 2011 bowhead whale census at Point Barrow, Alaska

Bowhead whales generally migrate into high Arctic waters in the summer months and move to lower latitudes in the wintertime. During the 1800s and early 1900s commercial whaling greatly reduced the numbers of bowhead whales in waters adjacent to the North Atlantic Ocean. In recent decades their numbers have been increasing. Thirteen sightings of a bowhead whale were recorded in four areas of the Gulf of Maine in 2012, 2014, and 2017 between latitudes 44°43’N and 41°36’N, far south of the normal range (54°N) for this species. Photographs obtained during these sightings were compared by experienced photo analysts and, based on scarring patterns, the sightings were confirmed to be of the same individual. The bowhead whale was observed alone, in addition to interacting in a social group and engaged in coordinated feeding with other mysticetes at times. The feeding and social behaviour of the bowhead whale was typical for the species but well south of its normal Arctic waters range and in the absence of conspecifics.

Observations of bowhead whales along the Northern Chukotka peninsula 2010–2012 with comparisons to 1994–1996 and 2002–2005

This paper contains information on the seasonal distribution of bowhead whales (Balaena mysticetus) in coastal waters of Chukotka (northeast Russia) in 2010–2012. Data from shore-based observation posts provides spatial and temporal information about whale distribution and migration in the coastal zones, as well as information about their relative numbers. The spring migration was observed only from Uelen, Russia (66°N, 149°W), near the northwestern entrance to the Bering Strait, and extended from the end of May through the first half of June. Some year-to-year differences in numbers and migration dynamics were observed. During summer, bowhead whales were sighted in the waters of the northern coast of Chukotka Peninsula in July and August. In 2010–2012, single whales and small groups of up to 4–8 whales were observed in the area for days making non-directed movements. Our observations in 2010–2012 demonstrated that many bowhead whales visited Chukotka coast in the autumn (September) before sea ice formation. From past observations, it appears that the autumn migration begins 2–3 weeks earlier on the northwestern coast of the Chukotka Peninsula than in the (northern) entry of the Bering Strait. The autumn migration of bowhead whales began with ice formation and ended with the complete freezing of the waters. Ice conditions appear to drive high variability in timing of the bowhead autumn migration. The northeastern Chukotka coast is one of the most important feeding areas for the Bering-Chukchi-Beaufort (BCB) bowhead whale population.

Age estimation for bowhead whales (Balaena mysticetus) using aspartic acid racemisation with enhanced hydrolysis and derivatisation procedures

Accurate determination of the ages of individual whales is key to developing effective conservation strategies for the bowhead whale (Balaena mysticetus). Previous attempts to develop reliable methods of age determination for this species have included using body length and baleen length measurements, baleen carbon cycling analysis, assessments of corpora accumulation, and aspartic acid racemisation (AAR; conversion of L to D enantiomers) measurements. Each of these methods has its limitations. The primary objective of this study was to improve the AAR analysis technique for determining age in bowhead whales in order to obtain consistent, reproducible results for D/L ratios for estimated ages. Using a modified AAR method, lenses from 68 bowhead whales were analysed and ages estimated. A comparison of the results to previous ageing by corpora counting or baleen carbon cycling methods for 11 of the whales showed smaller standard errors for the AAR analyses. The modified AAR methods applied in this study increase the precision of D/L measurements and provide improved bowhead whale AAR results.

Sightings of a bowhead whale (Balaena mysticetus) in the Gulf of Maine and its interactions with other baleen whales

Bowhead whales generally migrate into high Arctic waters in the summer months and move to lower latitudes in the wintertime. During the 1800s and early 1900s commercial whaling greatly reduced the numbers of bowhead whales in waters adjacent to the North Atlantic Ocean. In recent decades their numbers have been increasing. Thirteen sightings of a bowhead whale were recorded in four areas of the Gulf of Maine in 2012, 2014, and 2017 between latitudes 44°43’N and 41°36’N, far south of the normal range (54°N) for this species. Photographs obtained during these sightings were compared by experienced photo analysts and, based on scarring patterns, the sightings were confirmed to be of the same individual. The bowhead whale was observed alone, in addition to interacting in a social group and engaged in coordinated feeding with other mysticetes at times. The feeding and social behaviour of the bowhead whale was typical for the species but well south of its normal Arctic waters range and in the absence of conspecifics

Year-round foraging across large spatial scales suggest that bowhead whales have the potential to adapt to climate change

The ecological impact of environmental changes at high latitudes (e.g., increasing temperature, and decreased sea ice cover) on low-trophic species, such as bowhead whales, are poorly understood. Key to understanding the vulnerability of zooplanktivorous predators to climatic shifts in prey is knowing whether they can make behavioural or distributional adjustments to maintain sufficient prey acquisition rates. However, little is known about how foraging behaviour and associated environmental conditions fluctuate over space and time. We collected long-term movement (average satellite transmission days were 397 (± 204 SD) in 2012 and 484 (± 245 SD) in 2013) and dive behaviour data for 25 bowhead whales (Balaena mysticetus) equipped with time-depth telemetry tags, and used hierarchical switching-state-space models to quantify their movements and behaviours (resident and transit). We examined trends in inferred two-dimensional foraging behaviours based on dive shape of Eastern Canada-West Greenland bowhead whales in relation to season and sea ice, as well as animal sex and age via size. We found no differences with regards to whale sex and size, but we did find evidence that subsurface foraging occurs year-round, with peak foraging occurring in fall (7.3 hrs d-1 ± 5.70 SD; October) and reduced feeding during spring (2.7 hrs d-1 ± 2.55 SD; May). Although sea ice cover is lowest during summer foraging, whales selected areas with 65% (± 36.1 SD) sea ice cover. During winter, bowheads occurred in areas with 90% (± 15.5 SD) ice cover, providing some open water for breathing. The depth of probable foraging varied across seasons with animals conducting epipelagic foraging dives (&amp;lt; 200 m) during spring and summer, and deeper mesopelagic dives (&amp;gt; 400 m) during fall and winter that approached the sea bottom, following the seasonal vertical migration of lipid-rich zooplankton. Our findings suggest that, compared to related species (e.g., right whales), bowheads forage at relatively low rates and over a large geographic area throughout the year. This suggests that bowhead whales have the potential to adjust their behaviours (e.g., increased time allocated to feeding) and shift their distributions (e.g., occupy higher latitude foraging grounds) to adapt to climate-change induced environmental conditions. However, the extent to which energetic consumption may vary seasonally is yet to be determined.

Comparative embryology of Delphinapterus leucas (beluga whale), Balaena mysticetus (bowhead whale), and Stenella attenuata (pan-tropical spotted dolphin) (Cetacea: Mammalia).

Embryogenesis of cetaceans (whales, dolphins, porpoises) is best known in Stenella attenuata, the pan-tropical spotted dolphin, based on a remarkably complete and well-studied prenatal ontogenetic series. Our study expands understanding of cetacean embryology by adding two additional cetacean taxa: the beluga whale (Delphinapterus leucas, Odontoceti), and the bowhead whale (Balaena mysticetus, Mysticeti). We identify key features that characterize these taxa at specific stages and highlight heterochrony between the odontocetes and mysticetes. The toothed whales are more similar in developmental timing to each other than either is to Balaena. The two odontocete taxa, Stenella and Delphinapterus, share similar developmental trajectories while early Balaena specimens differ from the odontocetes. This developmental variation proves challenging to ascribe to the existing Carnegie staging system. Most notably, flippers, hindlimbs, and flukes all provide morphological traits for characterization within the Carnegie staging system. A presomitic Delphinapterus embryo is also described. This study applies the Carnegie staging system to two more cetacean taxa and forms a framework for future research on cetacean developmental genetics and the modeling of fetal growth.

Differences in individual bowhead whale Balaena mysticetus habitat use, foraging dive depth and diet during the peak feeding season

Shifts in zooplankton quantity and quality caused by climate change could challenge the ability of bowhead whales to meet their energetic requirements. When facing such selection pressure, intra-population variation dampens the negative effects and provides population-level resilience. Previous studies observed inter-individual diet variation in bowhead whales, but the mechanism responsible for the variation was undetermined. We investigated foraging variability in Eastern Canada-West Greenland bowhead whales using dietary biomarkers (stable isotopes, fatty acids) and movement data (satellite telemetry with time-depth recorders) from the same individuals. We found that bowhead whale individuals using distinct summer and fall foraging habitats displayed differences in horizontal movements, foraging dive depth, and diet. For individuals using the Canadian Arctic Archipelago habitat (Foxe Basin, Gulf of Boothia, Prince Regent Inlet, Lancaster Sound and Admiralty Inlet, Nunavut), they performed long distance movements across regions, and their foraging dive depth was generally shallow, but increased from July to November. These whales displayed higher δ13C and δ15N values and ratios of C16:1n7/C16:0. Individuals using the West Baffin Bay habitat (Cumberland Sound, Baffin Bay, Davis Strait) were more localized in their horizontal movements and consistent over time in their foraging dive depth, which was generally deeper. These whales displayed lower δ13C and δ15N values and ratios of C16:1n7/C16:0. Overall, this inter-individual variation in diet and foraging behaviour could indicate some niche variation which would be beneficial for the population under changing habitats and prey availability.

Necrose gordurosa perirrenal bilateral em cervo sambar (Rusa unicolor)

ABSTRACT: The gross and histopathological findings of perirenal fat necrosis in a sambar deer (Rusa unicolor) are described in a 6-year-old female deer that was necropsied after showing severe apathy, weight loss, recumbency, and death. At post-mortem examination, two large white to yellow, irregular, and encapsulated masses involving both kidneys were observed. Microscopically, these masses consisted of fat tissue presenting multifocal to coalescing areas of necrosis, diffuse infiltration of lymphocytes, macrophages, occasional plasma cells, and multinucleated giant cells. Multifocally, the necrotic sites were replaced by mineralization and fibrosis. The described condition has not been reported in deer and the exact mechanisms of development of perirenal fat necrosis remain to be determined. Massive fat necrosis has been reported in other animal species such as dogs, cats, pigs, goats, cattle, and whales (Balaena mysticetus). It is usually an incidental finding during post-mortem examination that needs to be differentiated from neoplasms originating from the adipose tissue, kidneys and adrenals, and disorders resulting from pancreatitis and obesity.

Research on the design of intelligent flowerpot science and education toys

With the development of science and technology, children’s attention has gradually shifted from accompanying their childhood toys to electronic entertainment products. Gradually, children have also stepped into the ranks of “bow heads”. In order to let children put down their mobile phones and go out of the house, the author germinated the idea of integrating nature into children’s toys. Based on the cognitive characteristics of 3-6-year-old preschool children, this study takes children’s science and education toys as the research object, analyzes and summarizes the development trend of intelligent science and education children’s toys at home and abroad, finds new innovative ideas for the functions and forms of intelligent science and education children’s toys, combines the cognitive characteristics of preschool children with the mysteries of nature, and hopes to help children understand colors and respect nature, Learn more about plants in nature.

Tales of middle Mesolithic cultural transformations and marine adaptation:

Submerged archaeological sites from the early Holocene, along the south-western and western Norwegian coastline are important sources of new information about stone-age human populations and coastal adaptation. In this article we present a Mesolithic hatchet made of bone that was found at the harbor floor at Kirkehavn in southern Norway in 1997. While radiocarbon dating proved this hatchet to be the oldest directly dated in Scandinavia (9884–9480 cal BP), aDNA analysis has identified the species from which this hatchet was made as either bowhead whale (Balaena mysticetus) or northern right whale (Eubalaena glacialis). The deposit of the hatchet must be understood in light of other contemporary ritual deposits along the south coast of Norway like the sub-merged Middle Mesolithic ritual site at Hummervikholmen and the cultural transformations taking place during this time. The result supplements the tale of new introductions in cultural practice and in material culture concurrently indicating the introduction of more complex hunter gatherer societies, while the distinctly marine adaptation continued on this part of the coast.

The Scene with a Sacrifiicial Bull Depicted on a Votive Relief from Tyras

In the article the marble relief of the Thracian Horseman, discovered in 1961 in Tyras, and dated by the first half of the 3rd century AD, is analyzed. The relief was found together with another limestone relief in room no. 29 of the large house no. ІІІ. It depicts a complex scene with multiple members. In the middle of the relief a rider is depicted. He moves to the right, facing full face. The rider holds a spear in his raised right hand. His horse slowly approaches the kneeling bull with its head down. The dog under the body of the horse attacks the bull. The photo and the drawing show Hercules on the right and the man with the torch on the left. In the background (behind the horse’s tail) stands a man with a torch and a tympanum (?). There is an object that looks like a seashell above the man. The author of the article suggests the following interpretation of the scene: the kneeling bull with bowed head is a sacrificial animal, the rider is a priest preparing to perform or performing a sacrifice, and Hercules is the recipient of the sacrifice. The rhyton held by Hercules emphasizes the meaning of the scene, since this vessel is intended for making or receiving a libation. The man standing on the right with ritual attributes is a dedicant. The shell above the man can be a symbol of rebirth after death. The complete analogies to the scenes depicted on the relief haven’t been known yet. However, there are several reliefs with similar individual elements, in particular, those depicting a sacrificial bull. There is no dedicatory inscription on the plate, so nothing is known about the social status and ethnic origin of the dedicant, nor about the name and epithet of the god to whom it was addressed. We can only make the following assumptions: 1. The house in which votive plates were found belonged to a wealthy family. This is evidenced by finds of coins and gold jewellery. The head of the family obviously belonged to the local elite. 2. Perhaps the owner of the house was Thracian by origin. He could have been a veteran of the Roman army or his descendant. It is known that in the 2nd — the first half of the 3rd centuries AD the Roman garrison was located in Tyras. It was recruited in Lower Moesia. 3. Perhaps a marble relief was made to order. In this case, the customer could choose the plot himself, which reflected an episode from his personal experience, in particular, participation in mysteries. The room in which votive plates were discovered probably served as a home sanctuary (a place where the family performed certain religious activities and placed offerings to the gods).

Tattoo Skin Disease in Cetacea: A Review, with New Cases for the Northeast Pacific.

Tattoo skin disease (TSD) is a poxviral dermatopathy diagnosed in cetaceans. We review the literature on TSD aetiology, clinical characteristics, pathology and epidemiology and evaluate immune responses against the virus. In addition, necropsy reports for fifty-five harbour porpoises (Phocoena phocoena), twenty-two Delphinidae and four Kogiidae stranded in northern California in 2018-2021 were checked for diagnostic tattoo lesions. TSD occurs in the Mediterranean, North and Barents Seas, as well as in the Atlantic, eastern Pacific and Indian Oceans in at least 21 cetacean species, with varying prevalence. Two cetacean poxvirus (CePV) clades are recognised: CePV-1 in odontocetes and CePV-2 in mysticetes. CePV-1 isolates were recovered from six Delphinidae and one Phocoenidae in the Americas, Europe and Hong Kong. Strains from Delphinidae are closely related. Among Phocoenidae, poxviruses were sampled only in harbour porpoises around the British Isles. CePV-2 isolates were obtained from southern right whales (Eubalaena australis) and a bowhead whale (Balaena mysticetus). In healthy animals, an immune response develops over time, with young calves protected by maternal immunity. Salinity and sea surface temperature do not seem to influence TSD prevalence in free-ranging cetaceans. High concentrations of immunotoxic halogenated organochlorines may cause a more severe clinical disease. Substitution and loss of genes involved in anti-viral immunity may favour CePV entry, replication and persistence in the epidermis. Off California, Delphinidae were less often (26.3%) affected by TSD than harbour porpoises (43.6%). Male porpoises were significantly more prone (58.1%) to show clinical disease than females (25%). Among males, TSD affected a high proportion of juveniles and subadults. TSD was not detected in the Kogiidae.