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This issue of the Anatomical Record is focused on the theme of Mysticete Anatomy. There are six included articles that explore the anatomy of the nasal region (Marquez et al., 2018; Maust-Mohl et al., 2018), larynx (Damien et al., 2018), lungs (Fetherston et al., 2018), sublingual fascia (Werth et al., 2018), and brain (Raghanti et al., 2018). These papers document anatomical features exhibited by mysticetes (baleen whales) and their related cousins (including other whales, and the semiaquatic moose and hippopotamus). This theme stems from a 2-day MiniConference on Mysticete Anatomy, hosted at the Icahn School of Medicine at Mount Sinai in New York City on May 2016. Anatomy is explored in the contexts of function and evolution of aquatic adaptations. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc. Anat Rec, 302:663-666, 2019. © 2019 Wiley Periodicals, Inc., (© 2019 Wiley Periodicals, Inc.)

We describe a case series of benign hepatic fatty tumors in 10 subsistence-harvested bowhead whales. Microscopic features included lipomatous and myelolipomatous masses. Extensive atrophy and/or destruction of hepatic parenchyma was not observed. No other significant disease was present except in an animal with unrelated chronic pleuritis. Based on our longitudinal case series (1980-2016) which identified 1-2 hepatic lipomas and myelolipomas in landed whales annually at Barrow, Alaska (USA), since 2012, hepatic lipomas and myelolipomas are occasionally seen in hunter-harvested bowhead whales. A conservative estimate for the percentage of bowhead whales with hepatic fatty tumors in landed whales in Barrow from 2012 to 2016 was 6% (7/111). The pathogenesis and exact cell origin of these benign fatty tumors in bowhead whales is undetermined. Assessment of further cases is warranted to better define the tissue distribution and pathogenesis of these tumors in bowhead whale liver.

This study addresses the question: why do rats get cataracts at 2 years, dogs at 8 years, and whales do not develop cataracts for 200 years? Whale lens lipid phase transitions were compared with the phase transitions of other species that were recalculated. The major phospholipids of the whale lens were sphingolipids, mostly dihydrosphingomyelins with an average molar cholesterol/phospholipid ratio of 10. There was a linear correlation between the percentage of lens sphingolipid and lens lipid hydrocarbon chain order until about 60% sphingolipid. The percentage of lens sphingolipid correlated with the lens lipid phase transition temperature. The lifespan of the bowhead whale was the longest of the species measured and the percentage of whale lens sphingolipid fit well in the correlation between the percentage of lens sphingolipid and lifespan for many species. In conclusion, bowhead whale lens membranes have a high sphingolipid content that confers resistance to oxidation, allowing these lenses to stay clear relatively longer than many other species. The strong correlation between sphingolipid and lifespan may form a basis for future studies, which are needed because correlations do not infer cause. One could hope that if human lenses could be made to have a lipid composition similar to whales, like the bowhead, humans would not develop age-related cataracts for over 100 years., (Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.)

This study presents refined epigenetic clocks for cetaceans, building on previous research that estimated ages in several species from bottlenose dolphins to bowhead and humpback whales using cytosine methylation levels. We combined publicly available data (generated on the HorvathMammalMethylChip40 platform) from skin (n = 805) and blood (n = 286) samples across 13 cetacean species, aged 0 to 139 years. By combining methylation data from different sources, we enhanced our sample size, thereby strengthening the statistical validity of our clocks. We used elastic net regression with leave one sample out (LOO) and leave one species out (LOSO) cross validation to produce highly accurate blood only (Median Absolute Error [MAE] = 1.64 years, r = 0.96), skin only (MAE = 2.32 years, r = 0.94) and blood and skin multi-tissue (MAE = 2.24 years, r = 0.94) clocks. In addition, the LOSO blood and skin (MAE = 5.6 years, repeated measures r = 0.83), skin only (MAE = 6.22 years, repeated measures r = 0.81), and blood only (MAE = 4.11 years, repeated measures r = 0.95) clock analysis demonstrated relatively high correlation toward cetacean species not included within this current data set and provide evidence for a broader application of this model. Our results introduce a multi-species, two-tissue clock for broader applicability across cetaceans, alongside single-tissue multi-species clocks for blood and skin, which allow for more detailed aging analysis depending on the availability of samples. In addition, we developed species-specific clocks for enhanced precision, resulting in four blood-specific clocks and eight skin-specific clocks for individual species; all improving upon existing accuracy estimates for previously published species-specific clocks. By pooling methylation data from various studies, we increased our sample size, significantly enhancing the statistical power for building accurate clocks. These new epigenetic age estimators for cetaceans provide more accurate tools for aiding in conservation efforts of endangered cetaceans.

Six species of cetaceans have been found to occur in the Chukchi Sea adjacent to the Pacific walrus rookery at Cape Vankarem: the gray whale, the bowhead whale, the humpback whale, the killer whale, the beluga whale, and the fin whale. The humpback whale is noted to have become abundant in the Chukchi Sea in the summer in recent years. The coastal mortality of cetaceans in a 100-km section in the western part of the distribution range of both gray and bowhead whales has been established to average 1.66 and 0.3 whales per year, respectively. Mostly young animals of 1–2 years of age appear to die, the main cause of death of which is predation by killer whales. The most common whales in that area in the summer–autumn period are humpback whales, which at the same time form significant concentrations in the coastal waters during the accumulation of the main food items. Both bowhead and gray whales are much less frequent, found rather irregularly, while despite the relative scarcity of encounters, these species account for the lion's share of all dead cetaceans. [ABSTRACT FROM AUTHOR]

Data from Bering‐Chukchi‐Beaufort Seas bowhead whales (Balaena mysticetus), harvested during 1973–2021 by aboriginal subsistence hunters, were used to estimate reproductive parameters: length at sexual maturity (LSM), age at sexual maturity (ASM), pregnancy rate (PR), and calving interval. Sexual maturity (N = 187 females) was determined from the presence/absence of corpora in the ovaries, or a fetus. Using sampling bias‐corrected logistic regression, LSM was estimated at 13.5 m, 95% CI [13.0, 13.8]. There was a downward trend in LSM over time, statistically significant with one method but marginal with another. A growth model translated this estimate to an ASM estimate of 23.5 years, 95% CI [20.4, 26.7]. Pregnancy rate was determined from mature females (N = 125), and from a subset limited to certain autumn‐caught whales (n = 37) to reduce bias. The PR was estimated at 0.46 globally, 95% CI [0.36, 0.55] and 0.38 for the autumn sample, 95% CI [0.20, 0.51]. Both estimated PRs are consistent with a 3‐year calving interval, because the larger estimate includes two cohorts of pregnant whales harvested in spring, and bowhead whale gestation is longer than 12 months. These analyses represent the most conclusive empirical estimates of ASM, LSM, and PR for this bowhead whale stock from the largest available data sets to date. [ABSTRACT FROM AUTHOR]

In a rapidly changing Arctic, multiple lines of evidence suggest that bowhead whale migration is changing. To explore these changes further, we used passive acoustic data to examine bowhead whale presence in the western Beaufort Sea (12 years) and Chukchi Plateau (11 years) spanning 2008 to 2022. Departure from the western Beaufort Sea shifted 45 days later over the 12‐year period. Summer presence increased at both sites, suggesting feeding areas within the Chukchi Sea are becoming more favorable. Likewise, findings from the Bering Strait suggest that some whales are remaining north of the Bering Strait for the winter instead of in the Bering Sea. These Pacific Arctic‐wide changes to migration have occurred over only one decade. Questions remain about prey availability in the Chukchi Sea, implications of migratory changes, such as a northward shift in the core overwintering area, and impact to communities south of the Bering Strait. Plain Language Summary: Bowhead whales are an important top predator in the Pacific Arctic. With increasing temperatures and decreasing sea ice, changes are occurring in the migration patterns of this "ecosystem sentinel" throughout the Pacific Arctic. We analyzed passive acoustic data from the western Beaufort Sea and Chukchi Plateau from 2008 to 2022. Whales are delaying their fall departure from the western Beaufort Sea and spending more time in the western Beaufort Sea and Chukchi Plateau, which, along with increased habitat use on the Chukchi Shelf, suggests that conditions there are becoming more favorable for feeding. Combined with previous data from the Bering Strait, which showed that some whales are spending winter in the southern Chukchi Sea rather than in the northern Bering Sea, these findings suggests that changes are occurring over a short period of time throughout the Pacific Arctic. A northward shift could put bowhead whales in the direct path of ships, especially along the western side of the Chukchi Sea, and impact whaling communities south of the Bering Strait. Key Points: Acoustic data reinforce known delay in bowhead fall departure from the western Beaufort Sea and overwintering in the southern Chukchi SeaIncreased presence in the western Beaufort Sea and Chukchi Plateau suggests these regions are becoming more favorable for bowhead feedingWhales are adapting to a rapidly changing Arctic, but changes and emerging threats may impact them and communities south of Bering Strait [ABSTRACT FROM AUTHOR]

The bowhead whale is a vital component of the maritime environment. Using deep learning techniques to recognize bowhead whales accurately and efficiently is crucial for their protection. Marine acoustic remote sensing technology is currently an important method to recognize bowhead whales. Adaptive SWT is used to extract the acoustic features of bowhead whales. The CNN-LSTM deep learning model was constructed to recognize bowhead whale voices. Compared to STFT, the adaptive SWT used in this study raises the SCR for the stationary and nonstationary bowhead whale whistles by 88.20% and 92.05%, respectively. Ten-fold cross-validation yields an average recognition accuracy of 92.85%. The method efficiency of this work was further confirmed by the consistency found in the Beaufort Sea recognition results and the fisheries ecological study. The research results in this paper help promote the application of marine acoustic remote sensing technology and the conservation of bowhead whales. [ABSTRACT FROM AUTHOR]

The 2019 ice-based survey of Bering-Chukchi-Beaufort Seas bowhead whales was challenged by missed survey effort, unusual ice conditions and frequent use of motor-powered skiffs by hunters. All three of these likely led to downward bias in the abundance estimate of Givens et al. (2021). Data were collected about boat excursions during the survey period. Indices of short-term whale abundance at the survey perch and short-term boat noise disturbance were computed from the available data, where ‘short term’ refers to a few hours. A generalised additive model (GAM) was fitted to the results, predicting short-term whale abundance as a smooth function of the boat noise disturbance index, after controlling for long-term variation in the whale passage rate over the course of the season. The fitted GAM was then used to predict passage with and without the presence of boat noise. The ratio of the integrals of these two predicted passage curves provided a correction factor which can be applied post hoc to the abundance estimate of Givens et al. (2021). Variance of this correction factor was estimated using two approaches and found to be small. A wide array of sensitivity analyses was conducted to examine the robustness of the result to potential changes in methodology and the correction factor was found to be quite stable. The estimated correction factor would inflate the original abundance estimate by about 12%, yielding a corrected abundance of 14,025 (CV = 0.228). We recommend this replace the original abundance estimate. [ABSTRACT FROM AUTHOR]

Information on factors contributing to the morbidity and mortality of the Bering–Chukchi–Beaufort seas stock of bowhead whales (Balaena mysticetus) is fundamental to its successful management and recovery. The Alaska Arctic coastline is remote and expansive, making monitoring for and gross examination of carcasses difficult. However, sighting data and imagery collected during aerial surveys in the eastern Chukchi (EC) and western Beaufort (WB) seas from 2009 through 2019 provide information on bowhead whale mortality. We present bowhead whale carcass data from the 2019 aerial surveys that add to the long series of consistent information on floating and beach-cast bowhead whale carcasses. The 2019 carcass data suggest an increased occurrence of probable killer whale (Orcinus orca) predation on bowhead whales in the WB. Eleven bowhead whale carcasses were photo-documented from July to October 2019 in the EC and WB study areas. Of the 11 carcasses documented, 7 had injuries consistent with probable killer whale predation—2 in the EC and 5 in the WB. Probable cause of death could not be assigned to four carcasses. No carcasses were associated with aboriginal subsistence hunting. Despite similar annual survey effort from 2009 to 2019, several compelling deviations in carcass numbers and locations were observed in 2019. Compared to 2009–2018, 2019 had the highest yearly number of documented carcasses and the most categorized as probable killer whale predation. Carcass locations exhibited a striking shift from the EC to the WB. Lastly, more carcasses were categorized as probable killer whale predation in the WB during 2019 than in 2009–2018 combined. [ABSTRACT FROM AUTHOR]

With global climate change and increasing ocean-based human activities, large whales face novel challenges in the Arctic seas. Understanding and assessing large whale occurrence and the links between occurrence and environmental variables in this region is a key issue in current management and conservation strategies for Arctic marine mammal species. During the Chukchi Sea Environmental Studies Program, large whale occurrence data were collected from vessel surveys during >56,909 km of observation effort in summer and autumn, 2008 to 2014, in the northeastern Chukchi, southern Beaufort, and Bering Seas. The most-recorded species were the Bowhead (Balaena mysticetus) and Gray (Eschrichtius robustus) Whales. Subarctic species recorded included the Humpback Whale (Megaptera novaeangliae), Fin Whale (Balaenoptera physalus), and Minke Whale (Balaenoptera acutorostrata). Sightings data were analyzed with respect to environmental variables: sea-surface temperature (SST), depth (m), and distance from shore (km), by month and year. Investigating occurrence associations with environmental parameters is a key element for predicting large whale trends in these Arctic seas and for understanding marine mammals as sentinels of oceanic shifts. [ABSTRACT FROM AUTHOR]

This study established the first baseline of changing elemental concentrations in bowhead whale baleen over time (1958–1999). From previously published stable isotope data, year, season (summer or winter), and location (Beaufort or Bering/Chukchi seas) were attributed to each sample. Thirteen elements (Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V, Zn) in baleen from nine subsistence-harvested bowhead whales (n = 138) were detected. Al, Cu, and Fe were the highest concentrations while Cd and V were among the lowest. Our data supports absorption as the main route of exposure to environmental elements rather than biomagnification due to bowhead whales' low trophic position. A linear mixed-effects model confirmed most elements' concentrations increased with time, while location and sex were insignificant explanatory factors. These temporal fluctuations were most likely a product of environmental changes due to a warming climate and human activities. [ABSTRACT FROM AUTHOR]

Bowhead whales occur in the Arctic year‐round. Their movements are largely correlated with seasonal expansions and reductions of sea ice, but a few recent extralimital sightings have occurred in the eastern and western North Atlantic and one was also documented in the western North Pacific over 50 years ago. Here we present details of a juvenile bowhead whale that was photographed and filmed from above and below the water while it was skim‐feeding in Caamaño Sound, BC, Canada on May 31, 2016. This sighting occurred over 2000 km southeast from the nearest known range for this species in the Bering Sea at a time that most bowhead whales in that region would have been migrating northeast. This sighting represents the first and only documentation of a bowhead whale in the eastern North Pacific to date. [ABSTRACT FROM AUTHOR]

The history of bowhead whaling and hunt management in the eastern and central Canadian Arctic is reviewed. Subsistence hunting of bowhead whales by Inuit resumed in the 1990s under co-management arrangements that were part of land-claims settlement agreements. Removals by whaling in both Canada and Greenland have been accounted for in IWC Scientific Committee assessments of the Eastern Canada-West Greenland (EC-WG) stock, but Canada, having withdrawn from IWC membership in 1982, has no legal obligation to consider IWC management advice. From 1994-2021 the total reported catch of bowheads in the central and eastern Canadian Arctic was 39 (not including struck-and-lost whales or whales that died from entanglement in fishing gear). Sixteen different communities, most of which had a long history of bowhead whaling prior to the arrival of commercial whalers, took at least one bowhead over that 27-year period. More than half of the recent catches have been by the communities of Igloolik, Sanijarak, Naujaat and Coral Harbour, all in the Foxe Basin-Repulse Bay-northern Hudson Bay region where at least occasional hunting of bowheads by local people had persisted until well into the 1970s. Greenland's reported landed catches totaled 8 from 2009-2015, with no successful hunts reported since 2015. Well over a third of the whales landed by both countries combined have been mature females, the most valuable class in terms of potential for population increase. Several factors in addition to hunting and entanglement in fishing gear are likely affecting EC-WG bowheads, including increased exposure to killer whale predation (linked to the massive reduction in sea ice) and other changes in ecological conditions driven primarily by climate change (e.g. more industrial activity, more vessel traffic, more noise). Recent analyses suggest the ECWG stock of bowheads has grown considerably since the end of commercial whaling, with best estimates of current abundance in the range of 6,000-7,000 individuals. Even though the population appears capable of sustaining present levels of removal and disturbance, it is important for monitoring efforts to continue in both Canada and Greenland, with regular Indigenous participation. [ABSTRACT FROM AUTHOR]

The Chukchi Sea environment changes considerably in physical and biological conditions, driven by the expanding volume of warm Pacific summer water. These environmental changes can affect the migration timing of baleen whales in the southern Chukchi Sea. However, few studies have been conducted in this area to determine the migration timing of bowhead whales (Balaena mysticetus), the only baleen whale species endemic to the Arctic region. In this study, we conducted a fixed passive acoustic monitoring of bowhead whales in the southern Chukchi Sea from July 2012 to October 2015 and compared the occurrence patterns of vocalizations to physical and biological environmental factors. Bowhead whale calls were detected in fall/winter and spring during the ice-freezing and retreating periods, respectively. The fall migration timing of bowhead whales through the southern Chukchi Sea was delayed in the years when the timing of sea ice formation was late, and it formed increasingly later in the years 2013, 2014, and 2012, in that sequence. Moreover, the sea surface temperature decreased before freeze-up, which affected the timing of fall migration of bowhead whales. There was no clear relationship between the occurrence of bowhead whale calls and the abundance of prey, especially in spring, suggesting that most bowhead whales use the southern Chukchi Sea as a corridor during their spring northward migrations. However, the occurrence of bowhead whales and high abundance of zooplankton in October–November present the possibility that bowhead whales expand their feeding area in the southern Chukchi Sea. [ABSTRACT FROM AUTHOR]

The remote and harsh environment that endemic Arctic whales (bowhead, narwhal and beluga) reside in has so far limited their exposure to many human activities. However, Arctic industrialisation coupled with increasingly accessible ice-free waters means these species increasingly co-occur, and are exposed to, a number of potentially impactful activities, many of which are directly or indirectly associated with marine vessels. We conducted a systematic map, using five search databases, to ascertain the current level of understanding relating to how Arctic whales respond to marine vessels and vessel-associated activities. We identified a limited volume of literature (n = 169), and a disparity in volume between species, subpopulations, and vessel types. Several vessel types are increasingly present in the Arctic (e.g. cruise ships, fishing vessels), yet received limited consideration. Similarly, several endangered subpopulations have received little attention. Only with sufficient understanding of the associated impacts of vessels can we develop appropriate management and mitigation measures which can effectively conserve these unique, vulnerable and inherently valuable species. [Display omitted] • Marine vessel traffic in the Arctic is increasing, and often overlaps with Arctic whale range (beluga, bowhead, narwhal). • We used a systematic map to review current knowledge of Arctic whale response(s) to vessels, and found research has been limited, and is unequal across species, stocks and vessel types. • Many endangered subpopulations have little research related to their response to vessels. • Vessel types that are increasing in the Arctic, e.g. fishing, cruise, have so far received limited research effort. • Knowledge gaps should be addressed to inform the development of proactive and adaptive vessel-related management approaches. [ABSTRACT FROM AUTHOR]

An ice‐based visual survey of the Bering‐Chukchi‐Beaufort Seas stock of bowhead whales (Balaena mysticetus) was conducted in spring 2019 near Utqiaġvik (formerly Barrow), Alaska. A Horvitz‐ Thompson‐type estimator is used to estimate population abundance from the resulting data, correcting for detection probabilities, whale availability within visual range, and whale passage during periods of missed effort. Analytical methods mirror those used for the 2011 survey as much as possible; however, unlike 2011, no simultaneous acoustic monitoring was conducted in 2019, so the availability correction factor had to be estimated from past years. The estimated abundance was 12,505 with 95% confidence interval of (7,994, 19,560) and a CV of 0.228. This estimated abundance is markedly lower than the 2011 estimate of 16,820, but the 2019 confidence interval wholly encompasses the 2011 interval. We do not interpret this finding as evidence of a decline for many reasons including: highly unusual ice conditions, an unusual migration route that was sometimes too distant from observers to detect whales, failure to conduct watch because of closed leads during the early weeks of the migration when numerous whales likely passed, an unusually short perch, and hunters’ heavy use of powered skiffs near the observation perch which likely disturbed the whales during the survey. Furthermore, bowhead health assessment information for 2019 suggests that harvested bowheads did not exhibit obvious reductions in health condition, and aerial surveys in summer 2019 indicated high calf production. Despite the challenges of this survey, the estimate is adequate for use with the International Whaling Commission’s management procedure and complies with the survey requirements of the Aboriginal Whaling Scheme. [ABSTRACT FROM AUTHOR]

Imagery and sighting data on bowhead whale (Balaena mysticetus) carcasses documented from 2009 to 2018 during aerial surveys in the eastern Chukchi and western Beaufort seas have provided evidence for killer whale (Orcinus orca) predation on bowhead whales of the Bering–Chukchi–Beaufort Seas stock. The Aerial Surveys of Arctic Marine Mammals (ASAMM) project provides information on distribution, behavior, and relative density of marine mammals. ASAMM surveys large areas of bowhead whale and killer whale summer and autumn habitat and offers consistent information on bowhead whale carcasses. Thirty-three bowhead whale carcasses were documented in July–October, from 2009 to 2018. Carcasses were distributed across the eastern Chukchi and western Beaufort seas from 141.6° W to 168.1° W and 68.9° N to 72.0° N. Carcass sighting rates (carcasses/1000 km) varied by month, year, and region. Statistical results suggest an alternating series of high and low annual carcass sighting rates. Eighteen bowhead whale carcasses having injuries consistent with probable killer whale predation were photo-documented: four each in 2016 and 2018, three each in 2013 and 2015, two in 2012, and one each in 2010 and 2017. Four carcasses, two in 2015 and one each in 2013 and 2018, were likely whales struck and lost during aboriginal subsistence hunting. Cause of death could not be determined for 11 carcasses. This study is the first systematic inquiry into non-harvest related mortality of bowhead whales in the U.S. Pacific Arctic and provides multi-year evidence for killer whale predation on bowhead whales in this portion of their range. [ABSTRACT FROM AUTHOR]

We used satellite telemetry to examine bowhead whale movement behavior, residence times, and dive behavior in the Alaskan Beaufort Sea, 2006 - 18. We explored the timing and duration of use of three subregions (western, central, eastern) within the Alaskan Beaufort Sea and applied a two-state switching state-space model to infer bowhead whale behavior state as either transiting or lingering. Transiting whales made direct movements whereas lingering whales changed direction frequently and were presumably feeding. In spring, whales migrated across the Alaskan Beaufort Sea in 7.17 ± 0.41 days, primarily off the continental shelf over deep water. During the autumn migration, whales spent over twice as much time crossing the Alaskan Beaufort Sea than in spring, averaging 18.66 ± 2.30 days, spending 10.05 ± 1.22 days in the western subregion near Point Barrow. Most whales remained on the shelf during the autumn migration and frequently dove to the seafloor, where they spent 45% of their time regardless of behavioral state. Consistent dive behavior in autumn suggests that the whales were looking for food while migrating, and the identification of lingering locations likely reflects feeding. The lack of lingering locations in the eastern and central subregions suggests that prey densities are rarely sufficient to warrant whales pausing their migration for multiple days, unlike in the western subregion near Point Barrow, where bowhead whales regularly lingered for long periods of time. [ABSTRACT FROM AUTHOR]

Abstract—The bay waters of the Sea of Okhotsk near the Shantar Islands are the most important summer grazing areas for bowhead whales (Balaena mysticetus) of the Okhotsk population. A hydrobiological survey during the period from July 12–28th, 2016, demonstrated that waters around the Shantar archipelago are characterized by high concentrations of humic substance supplied by the peat-laden banks of rivers flowing into the bays. The average chlorophyll concentrations in bottom waters of Uda and Academy bays were 1.1 and 4.3 mg/m3, respectively. Uda and Academy bays are mainly considered heterotrophic and autotrophic basins, respectively. The measured zooplankton biomass in Uda Bay ranged from 9.5 to 2513 mg/m3, averaging 736 mg/m3; the corresponding characteristics in Academy Bay were 0.38 to 3620 mg/m3, averaging 458 mg/m3. In the Shantar water area, copepods of the species Calanus glacialis were the dominant contributor in terms of zooplankton biomass and species abundance. During early summer, nine bowhead whales were sighted south off Feklistov Island and lone whales were recorded in the North Strait and at the mouth of Nikolai Bay. The low density of polar whales in the Shantar water area in early summer may be due to the low zooplankton biomass after spring bloom and the last spawning. [ABSTRACT FROM AUTHOR]

The Bering‐Chukchi‐Beaufort Seas (BCBS) bowhead whale (Balaena mysticetus) has been considered at low‐risk for entanglement injuries and ship strikes because their range is mainly north of commercial fisheries; nevertheless, changes to their arctic habitat, including a longer open water period and declining sea ice, have resulted in increasing commercial activity and concern about fisheries interactions. We examined interyear matches (between 1985 and 2011) from a photo identification project and identified whales that had acquired entanglement injuries. We estimated the probability of a bowhead acquiring an entanglement injury using two statistical methods: interval censored survival analysis and a simple binomial model. Both methods give similar results, suggesting a 2.2% (95% CI: 1.1%–3.3%) annual probability of acquiring a scar. We also include an entanglement scar frequency analysis of aerial photographs from the 2011 spring and fall surveys near Point Barrow, Alaska, which suggest 12.4% of live bowheads show evidence of entanglement scarring. Entanglement rates for the BCBS bowhead stock are lower than many other large whale stocks, and abundance has increased over the past 35 yr; however, our findings indicate that fishing gear entanglement is a more serious concern for the BCBS bowhead whale population than previously thought. [ABSTRACT FROM AUTHOR]

Real recordings of bowhead whale signals and numerical simulation were used to investigate the propagation of such signals in an Arctic-type shallow-water waveguide. The authors analyzed attenuation and distortion of whale signals with increasing distance in the following conditions: (1) a soft and hard bottom, (2) different whale depths, (3) surface waves, (4) additive noise, and (5) reception by a single hydrophone and a vertical array. Signal attenuation was estimated by the change in sound pressure level (SPL). Signal distortion was estimated by the change in the correlation coefficient for the spectrograms of received signals and the reference spectrograms. It is shown that, compared to signals from a single receiver, the attenuation and distortion characteristics of the array output signals are more stable and resistant to changes in whale depth, to possible, under Arctic conditions, significant variations in sound speed in the bottom along the acoustic path, and to the effects of additive noise. The results can be used for passive monitoring of bowhead whales on the Arctic shelf. [ABSTRACT FROM AUTHOR]

Abstract Aerial surveys for bowhead whales have been conducted with a relatively consistent methodology over the Alaskan Beaufort Sea since 1989. Sightings of bowhead whales in the central Alaskan Beaufort Sea in September 1997 and September 2014 were unusual in that hundreds of whales were observed within a few kilometers of local barrier islands. We compare bowhead whale sightings, river discharge data, wind records, and satellite imagery to argue that the large numbers of bowhead whales observed nearshore in September 1997 and 2014 resulted from favorable feeding conditions established by high river discharges and prior upwelling events. These results are then generalized in a simple binary-based mechanistic framework that links the relevant physics to occurrences of observed and potential feeding opportunities for bowhead whales in the central Alaskan Beaufort Sea and in other locales along the Beaufort coast. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Bowhead whales (Balaena mysticetus) have a nearly circumpolar distribution, and occasionally occupy warmer shallow coastal areas during summertime that may facilitate molting. However, relatively little is known about the occurrence of molting and associated behaviors in bowhead whales. We opportunistically observed whales in Cumberland Sound, Nunavut, Canada with skin irregularities consistent with molting during August 2014, and collected a skin sample from a biopsied whale that revealed loose epidermis and sloughing. During August 2016, we flew a small unmanned aerial system (sUAS) over whales to take video and still images to: 1) determine unique individuals; 2) estimate the proportion of the body of unique individuals that exhibited sloughing skin; 3) determine the presence or absence of superficial lines representative of rock-rubbing behavior; and 4) measure body lengths to infer age-class. The still images revealed that all individuals (n = 81 whales) were sloughing skin, and that nearly 40% of them had mottled skin over more than two-thirds of their bodies. The video images captured bowhead whales rubbing on large rocks in shallow, coastal areas—likely to facilitate molting. Molting and rock rubbing appears to be pervasive during late summer for whales in the eastern Canadian Arctic. [ABSTRACT FROM AUTHOR]

Each spring, most bowhead whales of the Bering-Chukchi-Beaufort (BCB) population migrate to the southeast Beaufort Sea and summer in Canadian waters. In August and September, they form aggregations, which are known to occur mainly in the shallow, shelf waters when oceanographic conditions promote concentration of their zooplankton prey. The movements of individual bowheads while they occupy these late summer habitats are less well known; our knowledge is based on photographic evidence and limited tagging studies conducted from 1982 to 2000. In this study, 85% (17) of the 20 satellite-tagged whales that could have spent some time in the Canadian portion of the Beaufort Sea during late summer 2006 to 2012 spent all or part of August and September there. We analyzed location data for 16 whales, using a two-state switching correlated random walk (CRW) behavioural model, and classified locations in the Canadian waters as associated with lingering behaviour (inferred foraging) or directed travel. We found that these whales spent the greatest proportion of their time lingering (59%), followed by traveling (22%), and transitioning between lingering and traveling (19%). Using only lingering locations for these tagged whales in all study years pooled, we calculated kernel densities and defined five areas within the 75% density contour as aggregation areas. Together, the five aggregation areas we defined comprised 25 341 km2, 14.1% of the total area used by these tagged whales in Canadian waters during August and September of the deployment years. Three aggregation areas were located in shallow waters of the Beaufort Sea Shelf and were used almost exclusively by immature tagged whales in our sample. Two other aggregation areas were observed, one in Darnley Bay and one in Viscount Melville Sound in the Canadian Arctic Archipelago. Each of these was used by one mature whale. Tagged whales were observed to use one or two aggregation areas in a single season, and rarely more. The proportion of lingering time spent in each aggregation area was highly variable among individuals. The largest aggregation area (10 877 km2), located over the Beaufort Shelf north of the Tuktoyaktuk Peninsula (5 - 52 m depth), was used by 13 of the 16 tagged whales, almost exclusively by the immature whales, including three of four that were tracked in two consecutive summers. The Beaufort Shelf overall (and possibly the Tuktoyaktuk Shelf, including the Outer Shelf, in particular) was especially important for immature bowhead whales, while mature whales used habitats beyond the Beaufort Shelf during late summer. Findings may be important to inform both decisions on management and mitigative actions relating to bowhead whale use of the Beaufort Shelf and studies that aim to improve our understanding of the prey base of BCB bowhead whales in the Canadian Beaufort Sea region. [ABSTRACT FROM AUTHOR]

We analyzed scarring data for Bering-Chukchi-Beaufort (BCB) Seas bowhead whales (Balaena mysticetus) harvested by Alaska Native hunters to quantify the frequency of line entanglement, ship strikes, and killer whale-inflicted injuries. We had 904 records in our database for whales landed between 1990 and 2012, and after data quality screening, we found 521 records containing information on scarring. Logistic regression was used to evaluate different combinations of explanatory variables (i.e., body length, sex, year, year-group) to develop a prediction model for each scar type. We also list bowhead whales that were harvested, found dead, or observed alive entangled in commercial line/fishing gear. Our findings suggest that about 12% of harvested bowheads show entanglement scars. Their frequency is highly correlated with body length and sex: about 50% of very large bowheads (> 17 m) show such scars, while whales under 9 m rarely do, and males show a significantly higher rate than females. Scars associated with ship strikes are infrequent and occur on ~2% of all harvested whales; body length, sex, and year were not significant factors. Scarring from attempted killer whale predation was evident on ~8% of landed whales. As with entanglement injuries, the frequency of killer whale scars was much higher (> 40%) on whales more than 16 m in length and statistically more frequent in the second half of the study (2002 - 12). Increased killer whale injuries in the recent decade are consistent with studies conducted on bowheads of the Eastern Canada-West Greenland population. The findings presented here reflect the most thorough analysis of injury rates from entanglement, ships, and killer whales for the BCB bowheads conducted to date. They indicate that (1) entanglement rates primarily from pot fishing gear (crab or cod or both) are relatively high for very large and presumably older bowheads, (2) collisions with ships are infrequent at present, and (3) scarring from killer whales is frequent on very large adult whales (> 17 m). Considering that bowhead habitat is changing rapidly (e.g., sea ice reduction), industrial ship traffic in the Arctic is increasing, and commercial fishing operations are expanding to the north, we strongly recommend that monitoring of scarring and injuries on harvested bowheads continue into the future as a means of documenting change. [ABSTRACT FROM AUTHOR]

We present findings on the prevalence and abundance of cyamid ectoparasites (Cyamus ceti) or "whale lice" on bowhead whales (Balaena mysticetus) harvested for subsistence in the Bering, Chukchi, and Beaufort Seas from 1973 to 2015. Cyamids were present on 20% of the 673 whales that were examined for cyamid ectoparasites. Logistic regression was used to determine factors associated with cyamid prevalence. The probability of cyamid presence increased with age, length, and improving body condition, but decreased over the past 35 years. Cyamid presence was also more probable on whales harvested in the spring than on those harvested in the fall. When present, cyamid abundance was typically low (< 10 per whale). Case histories provide ancillary information about the relationships between abundance of cyamids and their bowhead hosts. Environmental change and increasing anthropogenic disturbances are expected to occur in the Arctic regions inhabited by bowheads. We recommend continued monitoring of subsistence harvested whales for cyamids, as well as further investigations into the roles of environmental and anthropogenic variables in cyamid prevalence and abundance, as part of a comprehensive program of Arctic ecosystem assessment. [ABSTRACT FROM AUTHOR]

The evolution of baleen constituted a major evolutionary change that made it possible for baleen whales to reach enormous body sizes while filter feeding on tiny organisms and migrating over tremendous distances. Bowhead whales (Balaena mysticetus) live in the Arctic where the annual cycle of increasing and decreasing ice cover affects their habitat, prey, and migration. During the nursing period, bowheads grow rapidly; but between weaning and approximately year 5, bowhead whales display sustained baleen and head growth while limiting growth in the rest of their bodies. During this period, they withdraw resources from the skeleton, in particular the ribs, which may lose 40% of bone mass. Such dramatic changes in bones of immature mammals are rare, although fossil cetaceans between 40 and 50 million years ago show an array of rib specializations that include bone loss and are usually interpreted as related to buoyancy control. [ABSTRACT FROM AUTHOR]

Killer whales ( Orcinus orca) are increasing in occurrence and residence time in the eastern Canadian Arctic (ECA) in part due to a decrease in sea ice associated with global climate change. Killer whales prey on bowhead whales ( Balaena mysticetus) of the Eastern Canada-West Greenland (EC-WG) population, but their patterns of predation pressure and effect on the EC-WG population's ability to recover from historical whaling remain unknown. We analyzed photographs of individual bowhead whale flukes from five regions within the EC-WG population's geographic range (Cumberland Sound, Foxe Basin, Isabella Bay, Repulse Bay and Disko Bay), taken during 1986 and from 2007 to 2012, to estimate the occurrence of rake marks (parallel scars caused by killer whale teeth). Of 598 identified whales, 10.2 % bore rake marks from killer whales. A higher occurrence of rake marks was found in Repulse and Disko Bays, where primarily adult bowhead whales occur seasonally, than in Foxe Basin, where juveniles and females with calves occur. Older bowheads, which have had greater exposure time to killer whales due to their age, had higher occurrences of rake marks than juveniles and calves, which may indicate that younger whales do not survive killer whale attacks. A high proportion of adult females also had rake marks, perhaps due to protecting their calves from killer whale predation. In order to quantify the effect of killer whales on EC-WG population recovery, further research is needed on the relationship between the occurrence of rake marks and bowhead adult, calf, and juvenile mortality in the ECA, as well as more information about Arctic killer whale ecology. [ABSTRACT FROM AUTHOR]

Fifty-two eyes were collected and analyzed to estimate ages of 42 bowhead whales using the aspartic acid racemization aging technique. Between-eye and within-eye variance components for the ratio of the D and L optical isomers (D/L ratio) were estimated via analysis of variance using multiple measurements from nine whales with both eyes sampled and analyzed. For whales with more than one (D/L)act value, an inverse variance weighted average of the values was used as (D/L)act for the whale. Racemization rate ( kAsp) and D/L ratio at birth (D/L)0 were estimated using (D/L)act from 27 bowhead whales with age estimates based on baleen or ovarian corpora data and two term fetuses. The estimates were kAsp = 0.977 × 10−3/yr and (D/L)0 = 0.0250. The nonlinear least squares analysis that produced these estimates also estimated female age at sexual maturity as ASM = 25.86 yr. SE(age) was estimated via a bootstrap that took into account the SE of (D/L)act and the variances and covariance of kAsp and (D/L)0. One male exceeded 100 yr of age; the oldest female was 88. A strong linear relationship between kAsp and body temperature was estimated by combining bowhead data with independent data from studies of humans and fin whales. Using this relationship, we estimated kAsp and ASM for North Atlantic minke whales. [ABSTRACT FROM AUTHOR]

The article presents a study which obtained biological data on bowhead whales that were hunted in Disko Bay, West Greenland in April-May 2009-2011. The study took six female and one male bowhead whales for subsistence. It says that all of them were sexually mature and one of the females was pregnant. It mentions that the male was considered sexually mature and another female demonstrated no indications of recent pregnancy and had 7-8 corpora albicantia. It notes that the observations on reproduction and growth of the whales were consistent with that of Alaskan bowhead whales.

The article discusses a study which determined whether bowhead whale calls were directional. It states that a directional autonomous seafloor acoustic recorders (DASARs) array was put on the seafloor of Northstar island in Prudhoe Bay, Alaska. Results revealed that on average, calls of bowhead whales were directional.

The article focuses on agendas and issues discussed at the Third Intersessional Workshop on the Review of Maximum Sustainable Yield Rate (MSYR) for Baleen Whales held in Seattle, Washington from April 20 to 24, 2011. The findings of photo-identification studies of North Atlantic right whales, South Atlantic right whales and bowhead whales, among others, are detailed. The methodology employed for estimating the coefficient of variation (CV) and temporal autocorrelation for the calving proportion index and calving interval data is explained. The developments regarding issues listed in the Work Plan for Completion of the MSYR Review including other taxa, genetic data and environmental variability are also detailed.

The frequency distributions of bowhead whale (Balaena mysticetus) size classes were studied as functions of year, location, water depth, and date. Whales were classified by size and status as calves, small subadults (non-calves < 10 m); large subadults (10-13 m); and adults (> 13 m). Adults include mothers with calves, which were also counted separately. During mid-August to early October of 1982, 1984-86, and 1998-2000, calibrated vertical photography was used to obtain known-scale images of 901 different whales in waters up to 200 m deep between Flaxman and Herschel islands (146° to 139° W) in the central Beaufort Sea. Age composition of the whales photographed over all years of our study was calves 6.2%, small subadults 31.4%, large subadults 33.3%, and adults 29.1%. We found proportionally more subadults and fewer adults than are estimated to be in the overall population, and this result was found both before and after making allowance for reduced effort to obtain photographs early and late in the migration period. Thus parts of the central Beaufort Sea up to 200 m deep appear to be more heavily used by subadult bowheads than by adults in most years. Significant interannual variation existed in length-frequency distributions of whales among years, geographic subdivisions of the study area, water depth categories, and time periods. This variation was due to variable use of the study area by each size class in different years, differences in the water depths used by different size classes, and different migration timing by each size class. Iin all years, small subadult whales were the dominant group in shallow (< 20 m) nearshore habitats, and the size of the whales increased with increasing water depth. Timing of movements into and through the study area were also related to size class: small subadults arrived first in late August and departed in late September, and adults arrived last in late September. Mothers and calves arrived in early September and were common until at least early October. [ABSTRACT FROM AUTHOR]

The article presents the observations of western gray whales by ship-based whalers in feeding areas in the 19th Century. It notes that the migration routes and wintering areas of this endangered population of whales are considered to be unknown. For this reason, the ship-based whalers from the U.S. and other countries held an intensive hunt for bowhead whales and North Pacific right whales in the Sea of Okhotsk from 1840s-1870s. Voyage logbooks indicate that the American whalers encountered gray whales in the northeastern corner of the Okhotsk Sea between May-late August. However, no evidence was found on gray whale observation off northeastern Sakhalin Island where most observations occur.

The article presents a study which investigates the reidentifications of bowhead whales that were photographed in various years during their spring migration past Point Barrow in Alaska. The photographs include 40 different whales seen between 1984-1994. It notes that the differences between dates of initial sightings and subsequent sightings ranged from -31 to +23 days comparing month and day only. The study considers the models for predicting resighting date from initial sighting date, whale length and presence of calf. It was found out that the individual mature bowheads do not have a consistent migration timing past Barrow. This indicates a single stock of whales with a plastic schedule.

Three songs were recorded from bowhead whales (Balaena mysticetus) in Disko Bay, West Greenland, during 59 h of recordings via sonobuoys deployed on seven days between 5 and 14 April 2007. Song elements were defined by units following the protocol of previous description of bowhead whale song. The two most prominent songs were loud, complex, and repeated in long bouts on multiple recording days while the third song was much simpler and recorded on only one day. Bowhead whale simple calls and faint song elements were also recorded using digital audio tape recorders and a dipping hydrophone deployed from the sea ice approximately 100–150 km southwest of Disko Bay on three separate days suggesting that song is also produced in the central portion of Baffin Bay in winter. Songs recorded in Disko Bay are from an area where approximately 85% of the whales have been determined to be adult females. Although it is not known which sex was singing, we speculate that, as in humpback whales (Megaptera novaeangliae), male bowhead whales may sing to mediate sexual competition or mate selection behaviors. This is the first detailed description of springtime songs for bowhead whales in the eastern Arctic. [ABSTRACT FROM AUTHOR]

The article presents a study which explores the method for calculating the percentage of calves in the Bering-Chukchi-Beaufort Seas (B-C-B) bowhead whales. It showed that the percentage of calves in a bowhead population can offer information on whether the population is increasing, stable or decreasing. It also revealed that the method can give an estimate of the percentage of calves in the population with a photographic effort at Point Barrow. It is stated that the method can also integrate information on the timing of migration with the percentage of calves being observed for calf index surveys.

The article presents a study which evaluates the genetic variation in the mitochondrial control region of bowhead whales in the Western Arctic. Study shows that there were no significant differences detected in spatial and temporal comparisons along Alaska's North Slope. However, there was a significant difference between autumn and spring whales from St. Lawrence Island. Moreover, it was concluded that the genetic variation of bowhead whales is established from mitochondrial cytochrome B gene sequences amplified from ancient DNA.

Abstract: The bowhead whale (Balaena mysticetus) is a species endangered over much of its range that is of great cultural significance and subsistence value to the Inuit of Northern Alaska. This species occupies subarctic and arctic regions presently undergoing significant ecological change and hydrocarbon development. Thus, understanding the health status of the Bering–Chukchi–Beaufort Sea (BCBS) stock of bowhead whales is of importance. In this study, we evaluated the concentrations of six essential and non-essential elements (Zn, tHg, Ag, Se, Cu and Cd) in liver and kidney of bowhead whales (n =64). These tissues were collected from the Inuit subsistence hunt in Barrow, Wainwright and Kaktovik, Alaska between 1983 and 2001. Reference ranges of these elements (including previously reported data from 1983–1997) were developed for this species as part of a health assessment effort, and interpreted using improved aging techniques (aspartic acid racemization and baleen isotopic 13C methods) to evaluate trends over time with increased statistical power. Interactions between element concentrations and age, sex and harvest season were assessed. Age was found to be of highest significance. Sex and harvest season did not effect the concentrations of these elements, with the exception of renal Se levels, which were significantly higher in fall seasons. In addition, histological evaluation of tissues from whales collected between 1998–2001 was performed. Associations between concentrations of Cd in kidney and liver and scored histopathological changes were evaluated. Liver Cd concentration was strongly associated with the degree of lung fibromuscular hyperplasia (P =0.001) and moderately associated with the degree of renal fibrosis (P =0.03). Renal Cd concentration influenced the degree of lung fibromuscular hyperplasia and renal fibrosis (P =0.01). A significant age effect was found for both pulmonary fibromuscular hyperplasia and renal fibrosis, indicating age may be a causative factor. Improvements in aging techniques and the addition of histological indices help clarify the relationships between elements and the influence of life history parameters on concentrations of these elements and potential impacts on health. These data provide essential baseline input useful for monitoring the effects of arctic ecosystem change as it relates to global climate change and industrial development, as well as help inform epidemiological studies examining the public health implications of heavy metals in subsistence foods. [Copyright &y& Elsevier]

The age of bowhead whales captured by Native Alaskan hunters in the Bering, Chukchi and Beaufort Seas has been estimated via chemical analyses of the eye lenses, and other techniques. The racemization-age estimates indicate that bowhead whales ( Balaena mysticetus) have a lifespan of more than a century. Stone and ivory weapon fragments recovered from bowhead whales hunted in Wainwright and Barrow (Alaska) in 1981, 1992, 1993 and 1997, provided rough but independent assessments of the whales’ longevity; however, their date of manufacture was unknown. Adding further confirmation of these age estimates, this note describes bomb lance fragments recovered recently (2007) and about 30 years ago (1980) from bowhead whales harvested by Eskimo hunters that were “dateable” and likely manufactured between 1879 and 1885. [ABSTRACT FROM AUTHOR]

During the 16th and 17th centuries, Basque whalers travelled annually to the Strait of Belle Isle and Gulf of St. Lawrence to hunt whales. The hunting that occurred during this period is of primary significance for the North Atlantic right whale, Eubalaena glacialis (Müller, 1776), because it has been interpreted as the largest human-induced reduction of the western North Atlantic population, with ∼12250-21 000 whales killed. It has been frequently reported that the Basques targeted two species in this region: the North Atlantic right whale and the bowhead whale, Balaena mysticetus L., 1758. To evaluate this hypothesis and the relative impact of this period of whaling on both species, we collected samples from 364 whale bones during a comprehensive search of Basque whaling ports from the 16th to the 17th century in the Strait of Belle Isle and Gulf of St. Lawrence. Bones were found and sampled at 10 of the 20 sites investigated. DNA was extracted from a subset (n = 218) of these samples. Analysis of the mitochondrial cytochrome b region identified five whale species. The identification of only a single right whale bone and 203 bowhead whale bones from at least 72 individuals indicates that the bowhead whale was likely the principal target of the hunt. These results imply that this whaling had a much greater impact (in terms of numbers of whales removed) on the bowhead whale population than on the western North Atlantic right whale population. [ABSTRACT FROM AUTHOR]

Historical and other poor-quality samples are often necessary for population genetics, conservation, and forensics studies. Although there is a long history of using mtDNA from such samples, obtaining and genotyping nuclear loci have been considered difficult and error-prone at best, and impossible at worst. The primary issues are the amount of nuclear DNA available for genotyping, and the degradation of the DNA into small fragments. Single nucleotide polymorphisms offer potential advantages for assaying nuclear variation in historical and poor-quality samples, because the amplified fragments can be very small, varying little or not at all in size between alleles, and can be amplified efficiently by polymerase chain reaction (PCR). We present a method for highly multiplexed PCR of SNP loci, followed by dual-fluorescence genotyping that is very effective for genotyping poor-quality samples, and can potentially use very little template DNA, regardless of the number of loci to be genotyped. We genotyped 19 SNP loci from DNA extracted from modern and historical bowhead whale tissue, bone and baleen samples. The PCR failure rate was < 1.5%, and the genotyping error rate was 0.1% when DNA samples contained > 10 copies/µL of a 51-bp nuclear sequence. Among samples with ≤ 10 copies/µL DNA, samples could still be genotyped confidently with appropriate levels of replication from independent multiplex PCRs. [ABSTRACT FROM AUTHOR]

Based on a series of 11 abundance estimates over 23 years, the western Arctic population of bowhead whale (WABW) has recovered substantially since it was listed under the US Endangered Species Act. We evaluate extinction risk for WABW to determine if this population should be considered for reclassification under the ESA. Given the uncertainty associated with distinguishing process error and observation error, we consider three scenarios reflecting different assumptions for process error. We applied the quantitative criteria for recovery and delisting using the approach proposed by [Gerber, L.R., DeMaster, D.P., 1999. An approach to endangered species act classification of North Pacific humpback whales. Conservation Biology, 13, 1203–1214] for large whales. To further examine the monitoring process and make recommendations for future data needs, we then re-ran the model using progressively smaller sub-samples of the census data. As longer time series of data were considered, the fraction of outcomes consistent with a “delisting” decision increased. For the 10 and 11-census year subsets, data unequivocally support a decision to delist this population for the 3 scenarios. Furthermore, the IUCN criteria for endangered and vulnerable are not met for this population of bowhead whale under any of our scenarios. Results from the population projections and application of the risk classification criteria are consistent with a determination that the risk of extinction for this population is insignificant in the foreseeable future. [Copyright &y& Elsevier]

The article reports on a survey for bowhead whales in the North Atlantic Ocean along the ice edge between Greenland and Svalbard in April 2006. The sea was acoustically monitored continuously throughout the survey and at least two persons with binoculars actively searched for whales from the bridge of the vessel. Spring sitings were consistent with the belief that habitat selection by bowhead whales change with season. A dense layer of zooplankton was detected in those areas where the whales were observed. It is proposed that the whales found in the Fram Strait were feeding on the copepods along the ice edge.

Bowhead whales ( Balaena mysticetus) are distributed in the Arctic in five putative stocks. All stocks have been heavily depleted due to centuries of exploitation. In the present study, nucleotide sequence variation of the mitochondrial control region was determined from bone remains of 99 bowhead whales. The bones, 14C dated from recent to more than 50 000 bp , were collected on Svalbard (Spitsbergen) and are expected to relate to ancestors of the today nearly extinct Spitsbergen stock. Fifty-eight haplotypes were found, a few being frequent but many only found in one individual. The most abundant haplotypes of the Spitsbergen stock are the same as those most abundant in the extant Bering-Chukchi-Beaufort (BCB) Seas stock of bowhead whales. Although FST indicates a slight but statistically significant genetic differentiation between the Spitsbergen and the BCB stocks this was not considered informative due to the very high levels of genetic diversity of mitochondrial DNA haplotypes in both bowhead whale stocks. Other measures such as KST also indicated very low genetic differentiation between the two populations. Nucleotide diversity and haplotype diversity showed only minor differences between the Spitsbergen and BCB stocks. The data suggest that the historic Spitsbergen stock — before the severe bottleneck caused by whaling — did not have substantially more genetic variation than the extant BCB stock. The similar haplotypes of the Holocene Svalbard samples and the current BCB stock indicate significant migration between these two stocks and question the current designation of five distinct stocks of bowhead whales in the Arctic. [ABSTRACT FROM AUTHOR]