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Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator–prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under‐ice food web to meet its energy needs. In this study, we assessed whether polar bears maintained dietary energy density by prey switching in response to spatiotemporal variation in prey availability. We compared the macronutrient composition of diets inferred from stable carbon and nitrogen isotopes in polar bear guard hair (primarily representing summer/fall diet) during periods when bears had low and high survival (2004–2016), between bears that summered on land versus pack ice, and between bears occupying different regions of the Alaskan and Canadian Beaufort Sea. Polar bears consumed diets with lower energy density during periods of low survival, suggesting that concurrent increased dietary proportions of beluga whales (Delphinapterus leucas) did not offset reduced proportions of ringed seals (Pusa hispida). Diets with the lowest energy density and proportions from ringed seal blubber were consumed by bears in the western Beaufort Sea (Alaska) during a period when polar bear abundance declined. Intake required to meet energy requirements of an average free‐ranging adult female polar bear was 2.1 kg/day on diets consumed during years with high survival but rose to 3.0 kg/day when survival was low. Although bears that summered onshore in the Alaskan Beaufort Sea had higher‐fat diets than bears that summered on the pack ice, access to the remains of subsistence‐harvested bowhead whales (Balaena mysticetus) contributed little to improving diet energy density. Because most bears in this region remain with the sea ice year round, prey switching and consumption of whale carcasses onshore appear insufficient to augment diets when availability of their primary prey, ringed seals, is reduced. Our results show that a strong predator–prey relationship between polar bears and ringed seals continues in the Beaufort Sea. The method of estimating dietary blubber using predator hair, demonstrated here, provides a new metric to monitor predator–prey relationships that affect individual health and population demographics. [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]

Abstract Vessel traffic has been increasing rapidly in the Arctic, and within the Canadian Arctic, tourist vessels are the fastest growing maritime sector. Vessel traffic can cause a variety of impacts on whales, including ship strikes and acoustic disturbance. Here, the overlap between tourist vessels (e.g., pleasure craft/yachts and passenger vessels/cruise ships) and whale concentration areas is assessed within the Inuvialuit Settlement Region of the western Canadian Arctic. Different management measures which could be used to reduce impacts on whales are also assessed. Passenger vessels have had a relatively constant overlap with whale concentration areas through time, whereas pleasure craft have had a recent and rapid increase. Passenger vessels may have a greater impact on whales, compared to pleasure craft, since they are larger and travel faster. Excluding vessels from the two marine protected areas in the region would have no impact on whales within concentration areas, since vessels would likely just be displaced to adjacent areas with similar whale concentrations. Restricting vessels to the Canadian government's proposed low-impact corridor may reduce impact slightly, but creating a corridor completely outside of the known whale area could more significantly reduce the potential impact of vessels on whales in those areas. Restricting vessel speed within whale areas would also reduce the impact of passenger vessels, but would not likely reduce the impact of pleasure craft. Overall, a combination of management measures may be the best way to reduce impacts on whales in concentration areas. [ABSTRACT FROM AUTHOR]

As the Arctic warms and sea ice decreases, increased shipping will lead to higher ambient noise levels in the Arctic Ocean. Arctic marine mammals are vulnerable to increased noise because they use sound to survive and likely evolved in a relatively quiet soundscape. We model vessel noise propagation in the proposed western Canadian Arctic shipping corridor in order to examine impacts on marine mammals and marine protected areas (MPAs). Our model predicts that loud vessels are audible underwater when > 100 km away, could affect marine mammal behaviour when within 2 km for icebreakers vessels, and as far as 52 km for tankers. This vessel noise could have substantial impacts on marine mammals during migration and in MPAs. We suggest that locating the corridor farther north, use of marine mammal observers on vessels, and the reduction of vessel speed would help to reduce this impact. [ABSTRACT FROM AUTHOR]

In the Arctic, warming and concomitant reductions in sea ice will affect the underwater soundscape, with the greatest changes likely being linked to anthropogenic activities. In this study, an acoustic recorder deployed on an oceanographic mooring in western Fram Strait documented the soundscape of this area, which is important habitat for the Critically Endangered Spitsbergen bowhead whale population. The soundscape was quasi-pristine much of the year, with low numbers of ships traversing the area. However, during summer/autumn, signals from airgun surveys were detected > 12 h/day. Mean received peak-to-peak SPLs for loud airgun pulses reached 160.46 ± 0.48 dB 1 μPa when seismic-survey ships were close (at ~ 57 km). Bowhead whales were present almost daily October–April in all years, with singing occurring in almost every hour November–March. Currently, loud anthropogenic sound sources do not temporally overlap the peak period of bowhead singing. This study provides important baseline data for future monitoring. [ABSTRACT FROM AUTHOR]

Each spring, most Bowhead Whales (Balaena mysticetus) of the Bering-Chukchi-Beaufort (BCB) population migrate to the Canadian Beaufort Sea and Amundsen Gulf for summer feeding. Occasionally, Inuvialuit hunters and others observe beachcast (stranded) or adrift Bowhead Whale carcasses. From 1987 to 2016, 26 such occurrences were recorded. Most (65%) were found by Inuvialuit hunters travelling on the land, with the majority (54%) reported during 2000-2006. Bowhead Whale carcasses were found widely distributed throughout the region, with twice as many in Amundsen Gulf (65%) compared with the southeastern Beaufort Sea (35%). It was possible to measure or estimate standard length for 17 of 26 specimens, and all were either provisional 'subadults' (7-9.5 m; n = 10; 59%) or provisional 'mature adults' (13-16 m; n = 7; 41%). The cause(s) of mortality was not determined for any of the specimens. Whales in the 'subadult' group were likely 1-4 years old, while the 'mature adult' group were likely mostly mature animals (~25 y), including some potentially very old (>100 y). There was evidence or direct observation of Polar Bears (Ursus maritimus) and/or Grizzly Bears (U. arctos) scavenging at 60% of the carcasses for which presence or absence of bears or bear sign (scats and/or tracks) was reported. It is important to continue to record incidental observations of beachcast Bowhead Whales, as this may enable stranding rates to be evaluated. [ABSTRACT FROM AUTHOR]

An analysis of the stable isotopes of oxygen (δ 18 O) and hydrogen (δD) was used to examine the linkage between sea ice concentration and the migration of western arctic bowhead whales ( Balaena mysticetus ; WABW). We compared δ 18 O and δD variability along the length of WABW baleen with isotopic values of zooplankton prey from different WABW habitat, with published δ 13 C and δ 15 N data, and with historical sea ice records. Zooplankton signatures varied widely (δ 18 O = −13‰–56‰; δD = −220‰ to −75‰), with regional separation between winter (Bering Sea) and summer (eastern Beaufort Sea) habitats of WABW observable in δD. The δ 18 O and δD of WABW varied significantly along the length of baleen (δ 18 O = 8–18‰; δD = −180 to −80‰), confirming seasonal migration and reflecting distinct regional dietary variation in isotopes. WABW migration appears to have varied concomitant with temporal sea ice concentration (SIC) changes; in years with high SIC, the difference in δD of WABW baleen between seasonal habitats was significantly greater than low SIC periods. This work shows that SIC is not only a determinant of habitat accessibility for WABW, but baleen may also be a record of historical SIC and Arctic climate. [ABSTRACT FROM AUTHOR]

As a precautionary measure to protect the culturally-significant bowhead whale (Balaena mysticetus) from vessel strike, this paper explores the potential for having the International Maritime Organization endorse ships' routeing measures in the Bering Strait region. The confined nature of the Bering Strait forces both vessel traffic and the migrating Bering-Chukchi-Beaufort stock of bowhead whales to occupy the same narrow space, thus putting individual animals at risk of vessel strike. The potential for vessel strike may become exacerbated as the reduction of Arctic sea ice makes the Arctic increasingly accessible, allowing vessels to transit through the Strait in greater densities. In drawing from lessons learned in the successful reduction of vessel strike to the North Atlantic right whale (Eubalaena glacialis), the author provides broad recommendations for implementing ships' routeing measures in the Bering Strait region based on findings by Citta et al. (2012). It is recommended that both the western side of Big Diomede Island and the western side of St. Lawrence Island be designated as seasonal Areas To Be Avoided (ATBA) during fall months when bowheads are known to inhabit the area. Alternatively, it is proposed that Traffic Separation Schemes (TSSs) be implemented so that vessels must keep to the eastern side of both Big Diomede Island and St. Lawrence Island during this time. Both measures would reduce the amount of overlap between migrating bowhead whales and transiting vessel traffic, effectively reducing the potential for vessel strike. [ABSTRACT FROM AUTHOR]

Abstract: The Arctic is one of the fastest-changing parts of the planet. Global climate change is already having major impacts on Arctic ecosystems. Increasing temperatures and reductions in sea ice are particular conservation concerns for ice-associated species, including three endemic cetaceans that have evolved in or joined the Arctic sympagic community over the last 5M years. Sea ice losses are also a major stimulant to increased industrial interest in the Arctic in previously ice-covered areas. The impacts of climate change are expected to continue and will likely intensify in coming decades. This paper summarizes information on the distribution and movement patterns of the three ice-associated cetacean species that reside year-round in the Arctic, the narwhal (Monodon monoceros), beluga (white whale, Delphinapterus leucas), and bowhead whale (Balaena mysticetus). It maps their current distribution and identifies areas of seasonal aggregation, particularly focussing on high-density occurrences during the summer. Sites of oil and gas exploration and development and routes used for commercial shipping in the Arctic are compared with the distribution patterns of the whales, with the aim of highlighting areas of special concern for conservation. Measures that should be considered to mitigate the impacts of human activities on these Arctic whales and the aboriginal people who depend on them for subsistence include: careful planning of ship traffic lanes (re-routing if necessary) and ship speed restrictions; temporal or spatial closures of specified areas (e.g. where critical processes for whales such as calving, calf rearing, resting, or intense feeding take place) to specific types of industrial activity; strict regulation of seismic surveys and other sources of loud underwater noise; and close and sustained monitoring of whale populations in order to track their responses to environmental disturbance. [Copyright &y& Elsevier]

Although market-based incentives have helped resolve many environmental challenges, conservation markets still play a relatively minor role in wildlife management. Establishing property rights for environmental goods and allowing trade between resource extractors and resource conservationists may offer a path forward in conserving charismatic species like whales, wolves, turtles, and sharks. In this paper, we provide a conceptual model for implementing a conservation market for wildlife and evaluate how such a market could be applied to three case studies for whales (minke [Balaenoptera acutorostrata], bowhead [Balaena mysticetus], and gray [Eschrictius robustus]). We show that, if designed and operated properly, such a market could ensure persistence of imperiled populations, while simultaneously improving the welfare of resource harvesters. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this paper was to investigate and illustrate how insights gained from experience managing human activities in order to protect North Atlantic right whales (Eubalaena glacialis) along the heavily industrialized east coast of North America might be applied in the Arctic, where bowhead whales (Balaena mysticetus) face some of the same risks as right whales. The reduced extent and thickness of sea ice and the resultant longer open-water season have major, complex implications for the Arctic marine ecosystem. Increased maritime ship traffic and commercial fishing in the Arctic are bound to affect bowheads and Native (indigenous) hunting communities who depend on whales for subsistence and cultural identity. Bowheads and right whales were greatly depleted by commercial whaling in the 19th and early 20th centuries. While the Western Arctic bowhead population has been recovering steadily in recent decades, North Atlantic right whales remain highly endangered because of persistent lethal and sublethal vessel strikes and frequent entanglement in commercial fishing gear. Entanglement can be transitory or persistent, with debilitation lasting for months before the animal finally succumbs. Vessel strike and fishing gear trauma has been documented in bowheads, but at a much lower rate than in right whales. Initiatives intended to mitigate the impacts of ship traffic on North Atlantic right whales have included speed limits and routing changes. Those meant to reduce the incidence and severity of entanglements include the modification of gear design and gear deployment practices. Management measures need to be considered in advance in the Arctic in order to minimize the risks to bowhead whales as shipping and industrial fishing expand in the Arctic with ice retreat. [Copyright &y& Elsevier]

The article presents a study which examines the seasonal selection behavior of sea ice landscape of bowhead whales or Balaena mysticetus based on satellite tracking data of the whales across Eastern Canada-West Greenland. The study investigates the movement of the whales and their habitat selection throughout summer and winter seasons, and employs resource selection functions to evaluate their habitat selection behavior. The results show that bowhead whales preferred areas with low ice coverage, thin ice and small floe size during winter, while areas with high ice coverage, thick ice and large floe size during summer.

The article reports on the implications of sea ice cover on the bowhead whales' habitat in the western Arctic. The effects of sea ice cover on bowhead whale's, Balaena mysticetus, prey availability suggests that the diminution in sea ice cover will significantly increase prey availability. The western Arctic marine ecosystem is also inherently adaptable for bowhead whales and it opposes basin-scale characterization of extreme sea ice retreats, thinning, and wind-driven movements. Open water accrued accordingly in five small regions where bowhead whales were feeding or where prey availability were present, including the northern Chukotka coast and Beaufort slope in June; near Wrangel Island, Barrow Arc and Chukchi Borderland in September; and in Barrow Arc in November.

Abstract: Tissues of bowhead, beluga, and gray whales were analyzed for Ag, Cd, Cu, Se, Zn, THg and MeHg (belugas only). δ15N and δ13C in muscle were used to estimate trophic position and feeding habitat, respectively. Trace element concentrations in tissues were significantly different among whale species. Hepatic Ag was higher in belugas than bowheads and gray whales. Gray whales had lower Cd concentrations in liver and kidney than bowhead and belugas and a sigmoid correlation of Cd with length was noted for all whales. Renal and hepatic Se and THg were higher in belugas than in baleen whales. The hepatic molar ratio of Se:THg exceeded 1:1 in all species and was negatively correlated to body length. Hepatic and renal Zn in subsistence-harvested gray whales was lower than concentrations for stranded whales. Se:THg molar ratios and tissue concentrations of Zn may show promise as potential indicators of immune status and animal health. [Copyright &y& Elsevier]

Blubber and muscle were collected from male bowhead whales (n = 71) landed near Utqiaġvik (Barrow), Alaska, between 2006 and 2015 and analyzed for lipid content and concentrations of persistent organic pollutants (POPs) in order to determine levels and trends over the collection period. Collection year was a significant predictor of blubber concentrations for most classes of POPs, while for a few classes, animal length (proxy for age) was also a significant predictor. This is the first report on levels of PBDEs in bowhead whales; concentrations of these compounds are low (≤55 ng/g wet weight). Blubber concentrations were lower than those reported in samples collected between 1992 and 2000, and many POP classes in blubber declined significantly between 2006 and 2015. Concentrations of POPs in bowhead whale tissues, which are subsistence foods for Native Alaskan communities, appear to be declining at rates comparable with previously reported temporal trends in Arctic biota. • Blubber POPs were markedly lower in 2006–2015 than in samples from 1997 to 2000. • Most blubber POPs showed significant declining trends between 2006 and 2015. • Rates of decline similar to those reported for Arctic biota generally. • First report of PBDE levels in bowhead whales, which are mostly <3 ng/g, ww. [ABSTRACT FROM AUTHOR]

Aerial reconnaissance surveys were conducted in June, 1994, to document the distribution of Bowhead Whales in the coastal waters of Foxe Basin and Roes Welcome Sound during the spring migration. The summer distribution of Bowheads in northern Foxe Basin was examined using both aerial surveys and boat-based observers. Results indicated that there are potentially three migration routes used by Bowheads to enter Foxe Basin and that once in northern Foxe Basin. Bowheads aggregate in a well-defined area north of Igloolik Island. Three systemic aerialstrip surveys were done in August to estimate the number of surface whales present in northern Foxe Basin. Estimates of 256 q 31.3 and 284 q 48.6 Bowheads were derived from two useable surveys. [ABSTRACT FROM AUTHOR]