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In this study, we assess prey consumption by the marine mammal community in the northeast Atlantic [including 21 taxa, across three regions: (I) the Icelandic shelf, Denmark Strait, and Iceland Sea (ICE); (II) the Greenland and Norwegian Seas (GN); and (III) the Barents Sea (BS)], and compare mammal requirements with removals by fisheries. To determine prey needs, estimates of energetic requirements were combined with diet and abundance information for parameterizing simple allometric scaling models, taking uncertainties into account through bootstrapping procedures. In total, marine mammals in the ICE, GN, and BS consumed 13.4 [Confidence Interval (CI): 5.6–25.0], 4.6 (CI: 1.9–8.6), and 7.1 (CI: 2.8–13.8) million tonnes of prey year–1. Fisheries removed 1.55, 1.45, and 1.16 million tonnes year–1 from these three areas, respectively. While fisheries generally operate at significantly higher trophic levels than marine mammals, we find that the potential for direct competition between marine mammals and fisheries is strongest in the GN and weakest in the BS. Furthermore, our results also demonstrate significant changes in mammal consumption compared to previous and more focused studies over the last decades. These changes likely reflect both ongoing population recoveries from historic whaling and the current rapid physical and biological changes of these high-latitude systems. We argue that changing distributions and abundances of mammals should be considered when establishing fisheries harvesting strategies, to ensure effective fisheries management and good conservation practices of top predators in such rapidly changing systems.

Environmental change and increasing levels of human activity are threats to marine mammals in the Arctic. Identifying marine mammal hotspots and areas of high species richness are essential to help guide management and conservation efforts. Herein, space use based on biotelemetric tracking devices deployed on 13 species (ringed seal Pusa hispida, bearded seal Erignathus barbatus, harbour seal Phoca vitulina, walrus Odobenus rosmarus, harp seal Pagophilus groenlandicus, hooded seal Cystophora cristata, polar bear Ursus maritimus, bowhead whale Balaena mysticetus, narwhal Monodon monoceros, white whale Delphinapterus leucas, blue whale Balaenoptera musculus, fin whale Balaenoptera physalus and humpback whale Megaptera novaeangliae; total = 585 individuals) in the Greenland and northern Barents Seas between 2005 and 2018 is reported. Getis-Ord Gi* hotspots were calculated for each species as well as all species combined, and areas of high species richness were identified for summer/autumn (Jun-Dec), winter/spring (Jan-May) and the entire year. The marginal ice zone (MIZ) of the Greenland Sea and northern Barents Sea, the waters surrounding the Svalbard Archipelago and a few Northeast Greenland coastal sites were identified as key marine mammal hotspots and areas of high species richness in this region. Individual hotspots identified areas important for most of the tagged animals, such as common resting, nursing, moulting and foraging areas. Location hotspots identified areas heavily used by segments of the tagged populations, including denning areas for polar bears and foraging areas. The hotspots identified herein are also important habitats for seabirds and fishes, and thus conservation and management measures targeting these regions would benefit multiple groups of Arctic animals.

NRM was supported by Colciencias (Departamento Administrativo de Ciencia, Tecnología e Innovación, Colombia), the University of St Andrews, and NAMMCO. This study investigated the oceanic drivers of sei whale (Balaenoptera borealis) distribution in the central and eastern North Atlantic, and explored how distribution may have changed over almost three decades. Cetacean sightings data were available from Icelandic, Faroese and Norwegian surveys conducted throughout the central and eastern North Atlantic during summer between 1987 and 2015. Effective strip half width was estimated from the data to take account of variation in detection probability. Spatially-referenced environmental variables used as predictors in generalised additive models of sei whale relative density included: relief-related variables seabed depth, slope and aspect; monthly-varying physical oceanographic variables sea surface temperature (SST), mixed layer depth, bottom temperature, salinity, and sea surface height anomaly (SSH); and monthly-varying biological oceanographic variables chlorophyll-a concentration and primary productivity. Preliminary analysis considered which month (March-August) in the dynamic oceanographic variables explained most variability in sei whale density. Models including all variables (“full models”) could only be run for 1998-2015 because data for several variables were missing in earlier years. “Simple models" including only relief-related variables and SST were therefore run for 1987-89, and also for 1998-2015 for comparison. The best-fitting full model for 1998-2015 retained the covariates depth, May SST, May bottom temperature, July salinity, July SSH and July primary productivity. Of these, depth, May SST and July SSH were the strongest predictors of sei whale density. In the simple models for both 1987-89 and 1998-2015, depth (especially), May SST and seabed slope were the strongest predictors of sei whale density. The highest densities of sei whales were predicted in the Irminger Sea and over the Charles-Gibbs Fracture Zone; a pattern driven by large negative SSH, deep water (>1500m) and polar-temperate SST (5-12oC). There was some inter-annual variability in predicted distribution and there appears to be a northward expansion in distribution consistent with prey species responding to ocean warming. The models could be used to predict future distribution of sei whales based on future environmental conditions predicted by climate models. Publisher PDF

This study was financed by the Norwegian Research Council ICE whales grant (No. 244488/E10), The Foreign Ministry of Norway (Norwegian-Russian programme), WWF Sweden and the Norwegian Polar Institute. T.A.M. was supported in part by CEAUL (funded by FCT - Fundação para a Ciência e a Tecnologia, Portugal, through the project UID/MAT/00006/2013). The Arctic is experiencing rapid warming, and resultant sea ice losses represent a serious threat to ice-associated species in the region. This study explored the distribution and abundance of the 3 Arctic resident whale species: narwhals, bowhead and white whales, in the marginal ice zone and into the sea ice north of the Svalbard Archipelago. Line-transect surveys were conducted using a combination of helicopter-based and ship-based efforts in August 2015. Twenty-six sightings, involving 27 bowhead whales and 58 narwhals, occurred along the helicopter transects, while no whales were recorded along ship transects. No white whales were observed during these surveys. After correcting for surface availability, distance sampling produced abundance estimates of 343 (CV = 0.488) bowhead whales and 837 (CV = 0.501) narwhals within the 52 919 km(2) study area. Bowhead whales were predominantly seen close to the ice-edge, whereas narwhals were located deeper into the ice. To contextualize these results within the broader Svalbard cetacean community, all whale sightings from the Norwegian Polar Institute's Svalbard Marine Mammal Sighting Data Base, from the period of the survey, were mapped to compare general distributions. These opportunistic sightings included numerous cetacean species, especially seasonally occurring ones. However, white whales dominated in terms of the numbers of individuals reported. Our results suggest little spatial overlap between seasonally occurring whales and the 3 Arctic resident whales. Bowhead whales and narwhals were tightly associated with sea ice, and white whales were tightly coastal. In contrast, the seasonally occurring species were found over the shelf and along its edges. Publisher PDF

The common minke whale (Balaenoptera acutorostrata acutorostrata) is a boreo-arctic species, and the summer period is generally characterized by intensive feeding and consequently seasonal fattening at high latitudes. The fat deposited is stored as energy reserves for overwintering at lower latitudes where feeding is greatly reduced. It is therefore expected that their body condition on the summer grounds will reflect food availability during their most intensive feeding period and thus indicate how well the high-latitude ecosystems can support the populations. During the commercial catch operations on feeding grounds in Norwegian waters, body condition data (blubber thickness and girth) were collected from 10,556 common minke whales caught from 1993 to 2013. To investigate associations between condition and time/area, we applied the following three models: (1) multiple regression models with covariates, sex, year, latitude and longitude, to find significant coefficients of the covariate; (2) random effect models involving the random effects of variations by year or area and with sex as a fixed variable; (3) varying coefficient models, which were applied to investigate variation with year/area and to interpret covariate effects by visualizations. The significance of the estimated coefficients can be assessed by statistical tests. In conclusion, the total trend over the 2 decades of data available suggests a decrease in minke whale condition. However, this trend was most pronounced during the high summer season when we considered the seasonal effect over the annual sampling periods from April to September.

The application of genetics for the management of natural resources is expanding, and within this field, DNA registers will play an increasing role. The Norwegian minke whale DNA register, established in 1996, was designed primarily as a control system to detect any attempts at illegal trade of products derived from other stocks of minke whale, or other whale species, under cover of the legal Norwegian harvest originating from the Northeast Atlantic. The register contains genetic data for 7644 of 7751 whales landed in the period 1997–2010. Profiles are established from sequencing part of the mtDNA control region, analysis of 10 STRs and a sex-determining marker. Probabilities of genotypes matching between two randomly selected whales are 6.0−04 and 3.0−08 for five and eight of the STR loci, respectively. This permits verification of traded whale products via match to the register. The register has also been used in a number of ad hoc scientific studies resulting through the accumulation of genetic, demographic and biological data. Here, we review the register’s logistics, specifications and evaluate the potential to apply similar registers to control the exploitation of other marine species.

Forty-six sightings of bowhead whales have been reported from the Svalbard area between 1940 and 2009. But, only three of these sightings are reported prior to 1980. Most observations involve only one or two whales, but groups of up to seven individuals have been seen recently. Increased ship traffic, particularly cruise-based tourism, in the north undoubtedly provides more opportunities for spotting this species, and the establishment of a structured cetacean sighting programme, as well as increase in effort in documenting sightings from a wider marine user-community, likely all play a role in more records being documented in recent years. The absence of a dedicated monitoring programme for ice-associated cetaceans and the generally low scientific activity level in this field in Svalbard Waters hampers firm conclusions about the trends in abundance of bowhead whales in the Svalbard area.

Skaug, H. J., Frimannslund, L., and Øien, N. I. 2007. Historical population assessment of Barents Sea harp seals (Pagophilus groenlandicus). – ICES Journal of Marine Science, 64: 1356–1365: –. Harp seals are an important component of the Barents Sea ecosystem. Population size is estimated to have been around 6 million seals in 1875, when large-scale exploitation by Norwegian and Russian hunters started. The estimate is obtained by fitting a population dynamics model to all available sources of data on Barents Sea harp seals, but because of a lack of information about several key parameters in the model, the uncertainty associated with the estimate is large. A sensitivity study involving three different mechanisms for density-dependence results in a range estimate of 3–7 million seals in 1875.

A combination of heavy metals, organochlorines (OC) and fatty acids (FA) that reflect long-term deposition (1+ year) in tissues was used in a Canonical Discriminant Analysis (CDA) exploring population substructure in 104 minke whales Balaenoptera acutorostrata that were sampled in West Greenland, the Central and Northeast Atlantic Sea and in the North Sea in 1998. Using a CDA that included mercury and cadmium in muscle, liver and kidney, and eight OCs and four unsaturated FAs in blubber we were able to separate the whales into four subpopulations: 1) a West Greenland group, 2) a Central Atlantic group represented by whales from Jan Mayen, 3) a Northeast Atlantic group (Svalbard, Barents Sea and northwestern Norway), and 4) a North Sea group. During an assignment test based on the data transformation developed by the CDA, about 84% of the individuals were correctly assigned to the area where they had been caught. The highest degree of misassignment was between Jan Mayen and the Northeast Atlantic ...

Information on population structure is essential for estimating population demographics and managing the impacts of exploitation of North Atlantic minke whales ( Balaenoptera acutorostrata ). New approaches including assessment of geochemical signatures in tissues can assist in defining such structure. This study determined regional variations in long-term elemental diagnostics of stock differences among 159 minke whales harvested in West Greenland, the Northeast Atlantic Ocean and the North Sea in 1998. The diagnostics tested included mercury (Hg), selenium (Se) and cadmium (Cd) in various tissues, and the trace and major element composition of baleen. Supporting data was also gathered on δ 15 N and δ 13 C and stable lead isotope ratios. For female whales, significant differences in at least one long-term diagnostic element occurred between several areas. Existence of the following population substructure was inferred: (a) West Greenland, (b) a central group represented by whales from Jan Mayen, (c) a northeastern stock encompassing the Barents Sea, Svalbard and coastal Norway, and (d) the North Sea. These groups were consistent with those defined genetically by Andersen et al. [Mar. Ecol., Prog. Ser. 247 (2003) 263]. Males appeared to fall into similar groupings to females but because of smaller sample sizes fewer significant differences occurred between areas. Stable-isotopic values in minke whales suggested lower trophic-level feeding in this species than hitherto suspected, with significant dietary differences between areas. Variations in feeding habits appeared to explain part of the geographical variation in tissue Cd, but not tissue Hg or Se. Differences among elements with a relatively long biological half-life in specific tissues suggested that groups of minke whales have fidelity to certain summer feeding areas at least for several years.

Journal home page: http://www.int-res.com/journals/meps/ Humpback whales Megaptera novaeangliae in the North Atlantic Ocean were severely depleted by exploitation. With legal protection since 1955, substantial recovery is likely to have occurred, but information on abundance and rates of increase has been limited. We present an assessment of humpback whale abundance in the North Atlantic Ocean based upon capturerecapture estimates using naturally marked individuals. These data result from a long-term collaborative effort combining large-scale dedicated projects and incidental data collection, leading to extensive geographical coverage. The application of robust statistical techniques produces estimates of greater accuracy and precision than has previously been possible. Abundance estimates ranging from 5930 to 12 580 individuals, with coefficients of variation (CVs) from 0.07 to 0.39, were calculated for the West Indies breeding population using data from 1979 to 1993. The most precise estimate for the West Indies breeding population is 10 752 (CV = 0.068) for 1992 and 1993. Due to application of new analytical methods, these estimates are larger and more precise than those previously published from similar time periods. The average rate of increase for the West Indies breeding population over a 14 yr period was estimated to be 0.031 (SE = 0.005). The best available estimate for the entire North Atlantic population of humpback whales is 11 570 (95% CI 10 290 to 13 390) based upon samples from 1992 and 1993. However, this estimate may be biased downwards to an unknown extent due to heterogeneity in capture probabilities that do not influence the West Indies estimates.

Levels of radioactive caesium (137Cs) were determined in minke whales (Balaenoptera acutorostrata) from West Greenland, the Northeast Atlantic region and the North Sea. The sample consisted of muscle tissue from 135 minke whales caught in 1998 in 7 different areas: West Greenland, n=44; East Greenland, n=4; Jan Mayen, n=22; Svalbard, n=14; Barents Sea, n=20; Vestfjorden/Lofoten, n=14; the North Sea, n=17. Mean 137Cs levels in whales ranged from 0.298 (SD=0.083) Bq kg–1 wet weight around Svalbard to 1.319 (SD=0.587) Bq kg–1 wet weight in the North Sea. The finding of the highest caesium concentration in minke whales from the North Sea is in accordance with previous findings that 137Cs levels in the marine environment of the North Atlantic region decrease with increasing distance from major point sources (i.e. nuclear-fuel reprocessing plants in the UK and France, and outflow from the Baltic Sea containing 137Cs from the 1986 Chernobyl accident). The mean 137Cs levels in minke whales from Svalbard and the North Sea differed significantly from mean levels in the other areas. This difference supports the indications from other studies that groups of minke whales are resident for some time at their feeding grounds in the North Atlantic and may occur in separate stocks during summer.

A white humpback whale ( Megaptera novaeangliae ) was observed on several occasions off Svalbard, Norway, during August 2012. The animal was completely white, except for a few small dark patches on the ventral side of its fluke. The baleen plates were light-coloured, but the animal’s eyes had normal (dark) colouration. This latter characteristic indicates that the animal was not an albino; it was a leucistic individual. The animal was a full-sized adult and was engaged in ‘‘bubble-feeding’’, together with 1520 other humpback whales, each time it was seen. Subsequent to these sightings, polling of the marine mammal science community has resulted in the discovery of two other observations of white humpback whales in the Barents Sea area, one in 2004 and another in 2006; in both cases the observed individuals were adult animals. It is likely that all of these sightings are of the same individual, but there is no genetic or photographic evidence to confirm this suggestion. The rarity of observations of such white individuals suggests that they are born at very low frequencies or that the ontogenetic survival rates of the colour morph are low. Keywords: White humpback whale; Megaptera novaeangliae ; Svalbard; leucism (Published: 26 April 2013) Citation: Polar Research 2013, 32 , 19739, http://dx.doi.org/10.3402/polar.v32i0.19739

Two beaked whales identified as Sowerby's beaked whale (Mesoplodon bidens) were observed in sea state 0–1 on 16 July 1995 at 71°30′N 04°00′E in the Norwegian Sea. A number of morphological features, such as dentition, were clearly seen during the encounter. The Sowerby's beaked whale's core distribution is in the North Sea and the previous northernmost sighting was made at 63°06′N 00°41′E. According to the literature, the species has never been recorded in the polar zone. The sighting in the Norwegian Sea suggests that the current data on the species distribution is uncertain, and that its range may include the polar waters of the Norwegian Sea.

Regional sighting surveys with two independent observers on each vessel were conducted each year from 1996 to 2001. Northern minke whales (Balaenoptera acutorostrata) are mostly solitary animals and are only available for observation at moments when they surface to breath. Thus, a stochastic point process model is developed for how the data are generated. The hazard probability of initially sighting a whale that surfaces depends on relative spatial coordinates and on other covariates. The parameters of the model are estimated by maximum likelihood. To account for interannual variation in spatial distribution of minke whales, a random effects model is developed and estimated by comparing current and past (1989 and 1995) survey data. A simulation approach is taken to remove bias from parameter estimates and to assess the uncertainty in the results. For total abundance, the result is a log-normal confidence distribution with quantiles 107 205·exp(0.137z), i.e., an abundance estimate of 107 205 with a coefficient of variation of ≈0.14. Together with these and earlier survey data, past data on catch, mark–recapture, and satellite tracking are reviewed to elucidate distribution and migration patterns in Northeastern Atlantic minke whales.

Regional variation in PCBs and organochlorine (OC) pesticide concentrations was examined using the blubber of 155 minke whales (Balaenoptera acutorostrata) sampled in seven regions in the North Atlantic and European Arctic, including western and southeastern Greenland, the Norwegian Sea, the North Sea and the Barents Sea. The levels and relative proportions of OCs were also used to examine the boundaries for North Atlantic minke whale stocks previously defined by the International Whaling Commission (IWC). Concentrations of major OC groups (sigmaPCB, 89.1-22 800 ng/g lipid; sigmaDDT, 65.3-6280 ng/g lipid; sigmaCHL, 33.3-2110 ng/g lipid) generally increased from west to east, while HCH concentrations (sigmaHCH,1-497 ng/g lipid) showed the opposite trend. Statistical comparison between six regions using sex-adjusted least squared mean concentrations showed that minke whales from the Barents Sea had significantly higher concentrations of EPCBs than those from the Vestfjorden/Lofoten, the North Sea, and west Svalbard, as well as significantly higher sigmaDDT concentrations compared to west Greenland animals. The differences in concentrations suggest that west and southeast Greenland minkes may represent one group of whales, which are distinct from both the Jan Mayen minkes and those from other IWC defined stocks in northern European waters. Principal components analysis using proportions of 71 PCB congeners and 20 OC pesticides (of total OCs) did not reveal any major differences among groups although minkes from the North Sea were distinguished from those from Greenland waters by higher loadings of more highly chlorinated PCBs and recalcitrant OC pesticides. The general similarity in mean levels of sigmaPCBs, sigmaDDT and sigmaCHL, as well as mean principal components analysis scores, among minkes sampled at Jan Mayen, Svalbard, Vestfjorden/Lofoten, the North Sea and the Barents Sea suggests that the whales are quite mobile and may feed in multiple areas within the northeastern Atlantic.

After experimental surveys by ship-borne helicopter and fixed-wing aircraft in 1990, harp seal breeding patches were surveyed in the Greenland Sea pack-ice (the West Ice) in the spring of 1991. Combined estimates based on data from visual helicopter transects and aerial photographic transect surveys indicate a minimum total production in excess of 55,000 harp seal pups in the West Ice in 1991. Extreme weather conditions and an exceptional westerly distribution of the pack-ice impeded attempts to survey West Ice hooded seal pups in 1994. Classified counts suggest late births of harp seal pups in 1990 when compared to 1991. Less precise data suggest comparable timing of peak pupping but a wider temporal distribution of hooded seal births in 1994 than in 1991. Published results from analyses of still-camera and video material confirm that image-analysis may be used to obtain useful information on environmental conditions and the spatial distribution and sizes of seals in pack-ice breeding patches.

During the period 1977–1994 about 17,000 harp seal pups have been tagged in the Greenland Sea and about 18,000 in the White Sea. The numbers of recoveries since 1977 have been approximately 870 and 50, respectively, from the two tagging operations. The recaptures indicate that Greenland Sea harp seals share common feeding grounds with both Northwest Atlantic and White Sea harp seals, albeit not breeding grounds. Recaptures made 1 year or more after tagging during the commercial catch operations in the Greenland Sea have been used to estimate pup production for several years during the period 1977–1991. It is evident from the analyses that the assumptions of mark-recapture estimates are violated, probably most seriously so by violations of the randomness assumption and non-uniform distribution of tagged animals. A mechanism of non-permanent emigration is suggested to explain the source of the bias, but no data are available to correct it although a truncation of recapture data assuming that temporary emigrated seals have returned to the population upon reaching sexual maturity might prove useful. Although mark-recapture experiments as a tool to estimate pup production certainly involve many problems which need to be accounted for, they should at least be considered as valuable supplements to other direct methods such as aerial surveys. In the case of ice-breeding seals in the Greenland Sea, the logistics and operational constraints on aerial surveys might even leave mark-recaptures experiments the only feasible alternative at present.