Uria Lomvia Research Articles

Metals and other trace elements in plasma and feathers of seabirds breeding in Svalbard

We assessed the concentrations of metals and other trace elements in two of the most common seabird species breeding on Svalbard, the black-legged kittiwake (Rissa tridactyla) and the Brünnich's guillemot (Uria lomvia). Both of these species feed mostly on fish and crustaceans but have different foraging strategies, kittiwakes being surface feeders while guillemots are divers. We investigated the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb), selenium (Se) and zinc (Zn) in the plasma and body feathers of black-legged kittiwakes (n = 17), as well as in the body feathers of Brünnich's guillemots (n = 13). Samples were collected from adult birds at two time points, one week apart during July 2017 in Kongsfjorden, Svalbard. Of the non-essential trace elements, As was found at the highest median concentration at both the first (56.23 ng/g ww) and second (39.99 ng/g ww) sampling timepoints in the kittiwake plasma. When separating for the sexes, as well as sampling time, males sampled at the first sampling time point had significantly higher concentrations of As (median at 0.087 ng/g versus 0.039 ng/g) and Se (median 0.26 ng/g versus 0.16 ng/g) compared to males sampled at the second time point. There was no significant difference in plasma concentrations between females at first and second sampling time points. Kittiwake feathers contained significantly higher concentrations of As, Cd and Hg than guillemot feathers, while guillemot feathers had significantly higher concentrations of Cu, Pb and Zn. However, of the non-essential elements in both kittiwake and guillemot feathers Hg was found with the highest median concentrations at 5160 and 1080 ng/g, respectively, thus in kittiwakes exceeding the level of 5000 ng/g associated with adverse effect (e.g., impaired reproduction). Levels of Hg and Se found in the kittiwake feathers were higher than previous studies on seabirds in the Arctic.

Decades of monitoring plastic pollution in seabirds in Canada: Spatial, temporal, and methodological insights

Plastic ingestion by seabirds is an increasing issue worldwide, yet species can vary in ingestion based on ecological and morphological differences. This provokes the ecological question of which species are better suited to monitor plastic ingestion across regions and time. In Canada, we examined plastic ingestion in sympatric northern fulmars (Fulmarus glacialis), black-legged kittiwakes (Rissa tridactyla), thick-billed murres (Uria lomvia), and black guillemots (Cepphus grylle). Here, we present new data and compare to historical work to inform plastic pollution monitoring in Canada. In 2021, 51 % of fulmars, 7 % of kittiwakes and 7 % of murres contained plastic, whereas guillemots had no pieces >1 mm. Regardless of the methods used to collect and process samples, fulmars continue to have low levels of ingestion compared to the European Arctic, but high levels compared to other species in the Canadian Arctic, emphasizing their continued utility as a monitoring tool for plastic pollution in Canada.

Thick-billed Murres in breeding pairs migrate and overwinter far apart but in similar photic environments

Scheduling between mates in species with long-term pair bonds can be essential for positive fitness. The annual cycle in photoperiod is the primary environmental cue used by many animals to synchronize behavior and physiology among members of a population, and animals that migrate must have similar annual schedules to ensure successful breeding. However, we know little about whether members of mated pairs in migratory species experience similar photic environments across the year, which could allow for synchronization in annual phenology. Here, we used light-based geolocation to estimate positions of mated pairs of Thick-billed Murres (Uria lomvia, a seabird a.k.a. Brünnich’s Guillemot) which bred above the northern polar circle in Greenland. We tested the hypothesis that individuals in mated pairs occur in more similar locations and photic environments than randomly matched females and males. We found no difference in the amount of spatial separation or in the photic environment between mates and randomized heterosexual pairings. In general, the distance between females and males ranged from 1,198.5 km during August to 737.4 km during January. The sexes remained in photic environments with highly correlated photoperiods and moderately correlated times of solar noon in UTC. The spatial separation of, but similar photic environments experienced by, female and male murres regardless of pair status is probably adaptive by facilitating the synchronization of annual schedules between sexes, while allowing individuals in mated pairs the freedom to pursue the best foraging opportunities during migration and overwintering independent of their mate.

Canadian murre harvest management in the face of uncertainty: a potential biological removal approach

AbstractHow to manage harvest under great uncertainty is a fundamental question for many wildlife managers, particularly when resources necessary to estimate abundance or population trends are limited. The large Newfoundland and Labrador murre hunt is the only licensed harvest of seabirds in Canada. Though harvest of thick‐billed murres (Uria lomvia) and common murres (Uria aalge) has declined considerably since the 1960−1970s from >500,000 birds taken annually to approximately 100,000 annually in recent years, potential murre colony declines across the North Atlantic have again triggered concerns over the sustainability of murre harvest in Canada. The effect of current harvest is difficult to assess because there is considerable uncertainty in recent population size, trend, demographic rates, licensed harvest, fisheries bycatch, and illegal harvest. To assess the situation, we simulated the population size necessary to sustain current levels of approximated anthropogenic mortality using a potential biological removal approach, which simplifies and constrains population processes to a few key variables. Based on these simulations, the Canadian licensed harvest of thick‐billed murre is consistent with conservation management objectives, as is common murre licensed harvest and fisheries bycatch. Adding estimated illegal harvest resulted in unstainable mortality levels in both species. While wildlife managers will need to formally assess the relative costs and benefits of reducing uncertainty in this system through improved harvest and population monitoring, illegal harvest and commercialization need to be addressed to manage Canadian murre populations. Potential biological removal approaches can be a useful framework to assess harvest management decisions for marine birds and other data‐limited species.

Ice type matters: impacts of landfast and drift ice on body condition in a high Arctic seabird community

Sea ice, a central component of polar ecosystems, is undergoing profound changes due to climate change. In particular, the Arctic is experiencing unprecedented warming at quicker rates than other regions. This alarming trend of sea ice loss has dire consequences, with spill-over effects on the entire ecosystem, from phytoplankton to top predators. The complex and dynamic nature of sea ice gives rise to diverse habitats, each with the potential to affect larger ecosystems in different ways. However, our understanding of the relative importance of different ice types for higher trophic levels remains limited. To address this knowledge gap, we conducted a comprehensive study of the effects of drift ice, landfast ice, and total sea ice extent (landfast ice + drift ice) on the body condition of six species of polar-breeding seabirds using long-term monitoring data (2003-2021) from Kongsfjorden, Svalbard. These species fell into two categories: Arctic species (Little Auk Alle alle, Brünnich’s Guillemot Uria lomvia, and Glaucous Gull Larus hyperboreus) and “boreal” (or north temperate) species (Black-legged Kittiwake Rissa tridactyla, Arctic Skua Stercorarius parasiticus, and Great Skua Stercorarius skua). We found that the presence and extent of different types of sea ice may have different effects on seabird body condition. Though we did not find any relationship between total sea-ice extent and seabird body condition, drift ice and landfast ice extent did produce significant effects. For Arctic species, these effects were positive. For boreal species, the relationship between body condition and drift and landfast ice was more complex. Our study suggests that the use of a non-specific sea ice variable may mask the effects of sea ice on Arctic wildlife, highlighting the importance of not considering sea ice to be uniform and simple habitat.

Monitoring Canadian Arctic seabirds at the Prince Leopold Island Field Station, 1975–2023

The research station at Prince Leopold Island (PLI), initiated in 1975, was the first seabird monitoring site created in the Canadian Arctic. The island supports 150 000 breeding pairs of seabirds, principally thick-billed murres ( Uria lomvia Linnaeus 1758), black-legged kittiwakes ( Rissa tridactyla Linnaeus 1758) and northern fulmars ( Fulmarus glacialis Linnaeus 1761), along with ∼70 pairs of glaucous gulls ( Larus hyperboreus Gunnerus 1767) and several thousand black guillemots ( Cepphus grylle Linnaeus 1758). Baseline observations of seabird breeding biology were made during 1975–1977. Subsequent monitoring has taken place in 22 of the 47 seasons, with work during 2001–2003 replicating the original baseline studies. Population trends of breeding seabirds have shown kittiwakes (sharply) and murres (gradually) increasing, while gulls (definitely) and fulmars (likely) have declined. The most striking scientific findings from PLI were related to the effect of annual ice break-up on seabird phenology, clutch size, and reproductive success. For contaminant research, PLI has become one of the core monitoring sites in Canada and internationally, documenting dramatic changes in concentrations of various contaminants in the Arctic marine environment. Given the international impact of research and monitoring at PLI for almost five decades, the continuation of seabird research at PLI, the most important seabird colony in the Canadian Arctic, is essential.

Spatiotemporal patterns of low and highly pathogenic avian influenza virus prevalence in murres in Canada from 2007 to 2022—a case study for wildlife viral monitoring

Migratory seabirds move across ocean basins and are one of the primary reservoirs of low pathogenic avian influenza virus (LPAIV). This includes the millions of thick-billed murres ( Uria lomvia) and common murres ( Uria aalge) that are distributed across northern hemisphere oceans. In response to increasingly frequent detections of highly pathogenic avian influenza virus (HPAIV) in Europe in 2020–2021, avian influenza virus (AIV) monitoring in wildlife has increased. We compiled data from murres tested for AIV in Canada between 2007 and 2022 to quantify spatiotemporal variation in the prevalence of LPAIV and HPAIV in these birds. No HPAIV was detected in murres prior to 2022, but HPAIV was present in 46% of both live/harvested and found dead murres in the northwestern Atlantic in 2022 with prevalence peaking at 63% among live birds in the summer. In the eastern Canadian Arctic, HPAIV prevalence in 2022 was <1% while LPAIV prevalence was 21%, which was significantly higher than previous sampling years. Power analyses suggest approximately 100 samples from breeding murres should be collected annually per colony or region to detect moderate changes in HPAIV prevalence. These analyses inform robust monitoring of viruses in wildlife, with implications for conservation, harvest management, and public health.

Influence of sea ice concentration, sex and chick age on foraging flexibility and success in an Arctic seabird.

Declining sea ice and increased variability in sea ice dynamics are altering Arctic marine food webs. Changes in sea ice dynamics and prey availability are likely to impact pagophilic (ice-dependent and ice-associated) species, such as thick-billed murres (Uria lomvia), through changes in foraging behaviour and foraging success. At the same time, extrinsic factors, such as chick demand, and intrinsic factors, such as sex, are also likely to influence foraging behaviour and foraging success of adult murres. Here, we use 3 years of data (2017-2019) to examine the impacts of environmental conditions (sea ice concentration and sea surface temperature), sex and chick age (as a proxy for chick demand) on foraging and diving behaviour (measured via biologgers), energy expenditure (estimated from activity budgets) and foraging success (measured via nutritional biomarkers) of thick-billed murres during the incubation and chick-rearing stages at Coats Island, Nunavut. Murres only exhibited foraging flexibility to environmental conditions during incubation, which is also the only stage when ice was present. When more ice was present, foraging effort increased, murres foraged farther and made deeper dives, where murres making deeper dives had higher foraging success (greater relative change in mass). During incubation, murre behaviour was also influenced by sex of the individual, where males made more and shorter trips and more dives. During chick-rearing, murre behaviour was influenced primarily by the sex of the individual and chick age. Males made shallower dives and fewer dive bouts per day, and more dives. Birds made longer, deeper dives as chicks aged, likely representing increased intra-specific competition for prey throughout the season. Our results suggest variation in sea ice concentration does impact foraging success of murres; however, sex-specific foraging strategies may help buffer colony breeding success from variability in sea ice concentration.

Spatial distribution of selenium-mercury in Arctic seabirds

Mercury (Hg) is a metallic trace element toxic for humans and wildlife that can originate from natural and anthropic sources. Hg spatial gradients have been found in seabirds from the Arctic and other oceans, suggesting contrasting toxicity risks across regions. Selenium (Se) plays a protective role against Hg toxicity, but its spatial distribution has been much less investigated than that of Hg. From 2015 to 2017, we measured spatial co-exposure of Hg and Se in blood samples of two seabird species, the Brünnich's guillemot (Uria lomvia) and the black-legged kittiwake (Rissa tridactyla) from 17 colonies in the Arctic and subarctic regions, and we calculated their molar ratios (Se:Hg), as a measure of Hg sequestration by Se and, therefore, of Hg exposure risk. We also evaluated concentration differences between species and ocean basins (Pacific-Arctic and Atlantic-Arctic), and examined the influence of trophic ecology on Hg and Se concentrations using nitrogen and carbon stable isotopes. In the Atlantic-Arctic ocean, we found a negative west-to-east gradient of Hg and Se for guillemots, and a positive west-to-east gradient of Se for kittiwakes, suggesting that these species are better protected from Hg toxicity in the European Arctic. Differences in Se gradients between species suggest that they do not follow environmental Se spatial variations. This, together with the absence of a general pattern for isotopes influence on trace element concentrations, could be due to foraging ecology differences between species. In both oceans, the two species showed similar Hg concentrations, but guillemots showed lower Se concentrations and Se:Hg than kittiwakes, suggesting a higher Hg toxicity risk in guillemots. Within species, neither Hg, nor Se or Se:Hg differed between both oceans. Our study highlights the importance of considering Se together with Hg, along with different species and regions, when evaluating Hg toxic effects on marine predators in international monitoring programs.

Photo Census Surveys of Thick-Billed Murres (Uria lomvia) at Cape Parry Migratory Bird Sanctuary, Northwest Territories

Photo Census Surveys of Thick-Billed Murres (Uria lomvia) at Cape Parry Migratory Bird Sanctuary, Northwest Territories

The consumption of ice-derived resources is associated with higher mercury contamination in an Arctic seabird

Sea ice plays a fundamental role in Arctic marine environments, by driving primary productivity and sustaining ice-associated ecosystems. Simultaneously, sea ice influences the contamination of Arctic marine organisms, by modifying contaminant cycles or their bioavailability. Changes in sea ice conditions could therefore profoundly impact the functioning of Arctic marine food webs and their contamination. Top predators such as seabirds, which are subject to bioaccumulation and biomagnification of contaminants, are particularly exposed. In this context, the present study aims to investigate the influence of sea ice and of the use of ice-derived resources on the contamination of seabirds by mercury (Hg). To this end, eggs of thick-billed murres (Brünnich's guillemots, Uria lomvia; n = 60) were collected on Prince Leopold Island (Canadian High Arctic) during four years of varying ice conditions (2010–2013). Trophic tracers (i.e., Highly Branched Isoprenoids, HBIs – an indicator of the use of ice-derived resources; carbon and nitrogen stable isotopes – indicators of foraging habitats and trophic status), as well as total Hg concentrations were quantified. Results showed that feeding on ice-derived resources (as indicated by HBI concentrations) was positively correlated to sea ice cover, and both positively influenced Hg concentrations in murre eggs. However, when testing for the best predictor with model selection, sea ice concentration only drove Hg contamination in murres. This work provides new insights into the role of sea ice and ice-derived resources in the contamination by Hg of Arctic wildlife. Further research is now needed to better understand the relationship between sea ice and Hg contamination in Arctic biota and its underlying mechanisms, but also to identify Hg sources in rapidly changing environmental conditions in the Arctic.

Quantifying marine traffic intensity in Northwest Greenland and the potential disturbance of two seabird colonies

Marine traffic poses a growing threat to wildlife in the marine environment, including Arctic seabirds, which are exposed to high vessel densities when breeding in coastal areas. However, little is known about the magnitude of the problem. Here, we utilized underwater acoustic monitoring to quantify marine traffic and above-water disturbances at two thick-billed murre colonies in Greenland in 2016. We detected a total of 307 vessels, and only 4 % was known from automatic monitoring systems. Based on proximity, noise emission, and boating behavior, we classified 11 vessels as disturbing and an additional 12 as potentially disturbing for the seabirds. One colony facing population decline was located closest to the main boating route and experienced 2–5 times more disturbances than the other (increasing) colony, suggesting a negative impact of marine traffic. Our study shows that underwater acoustics can be a useful method to quantify above-water disturbances of seabird colonies.

Demographic responses of Arctic seabirds to spring sea-ice variations

The Arctic experiences a rapid retreat of sea-ice, particularly in spring and summer, which may dramatically affect pagophilic species. In recent years, the decline of many Arctic seabird populations has raised concerns about the potential role of sea-ice habitats on their demography. Spring sea-ice drives the dynamics of phytoplankton blooms, the basis of Arctic food webs, and changes in spring sea-ice have the potential to affect the demographic parameters of seabirds through bottom-up processes. To better understand the effects of spring sea-ice on Arctic seabirds, we investigated the influence of spring sea-ice concentration on the survival and breeding success of three seabird species with contrasted foraging strategies in two Svalbard fjords in the high Arctic. We examined these relationships using long-term demographic data (2005–2021) from black-legged kittiwakes (Rissa tridactyla), Brünnich guillemots (Uria lomvia), and little auks (Alle alle). Spring sea-ice concentration was positively related to both the survival and breeding success of little auks, suggesting a higher sensitivity of this species to spring sea-ice. By contrast, the two other species were not particularly sensitive to changes in spring sea-ice, even though a potentially spurious negative effect on the breeding success of black-legged kittiwakes was observed. Overall, the study suggests that spring sea-ice may be involved in the demography of Arctic seabirds, but probably does not play a major role.

Lower nutritional state and foraging success in an Arctic seabird despite behaviorally flexible responses to environmental change

The degree to which individuals adjust foraging behavior in response to environmental variability can impact foraging success, leading to downstream impacts on fitness and population dynamics. We examined the foraging flexibility, average daily energy expenditure, and foraging success of an ice-associated Arctic seabird, the thick-billed murre (Uria lomvia) in response to broad-scale environmental conditions at two different-sized, low Arctic colonies located <300 km apart. First, we compared foraging behavior (measured via GPS units), average daily energy expenditure (estimated from GPS derived activity budgets), and foraging success (nutritional state measured via nutritional biomarkers pre- and post- GPS deployment) of murres at two colonies, which differ greatly in size: 30,000 pairs breed on Coats Island, Nunavut, and 400,000 pairs breed on Digges Island, Nunavut. Second, we tested whether colony size within the same marine ecosystem altered foraging behavior in response to broad-scale environmental variability. Third, we tested whether environmentally induced foraging flexibility influenced the foraging success of murres. Murres at the larger colony foraged farther and longer but made fewer trips, resulting in a lower nutritional state and lower foraging success compared to birds at the smaller colony. Foraging behavior and foraging success varied in response to environmental variation, with murres at both colonies making longer, more distant foraging trips in high ice regimes during incubation, suggesting flexibility in responding to environmental variability. However, only birds at the larger colony showed this same flexibility during chick rearing. Foraging success at both colonies was higher during high ice regimes, suggesting greater prey availability. Overall, murres from the larger colony exhibited lower foraging success, and their foraging behavior showed stronger responses to changes in broad-scale conditions such as sea ice regime. Taken together, this suggests that larger Arctic seabird colonies have higher behavioral and demographic sensitivity to environmental change.

Effects of chemical dispersants on feathers from Arctic seabirds

Chemical dispersion is an oil spill response strategy where dispersants are sprayed onto the oil slick to enhance oil dispersion into the water. However, accidental application could expose seabirds to dispersants, thereby negatively affecting their plumage. To understand the possible impacts on seabirds, feathers from common eider (Somateria mollissima) and thick-billed murre (Uria lomvia) were exposed to different dosages of the dispersant Dasic Slickgone NS. For all exposure dosages the feathers increased in weight, and mostly for common eider. Analysing the feather microstructure, e.g., the Amalgamation Index, showed that larger damages were found on thick-billed murre than common eider. A no-sinking limit was established at 0.109 ml/m2. Relating this value to desktop simulations of potential sea-surface dosages in real-life situations, and to published accounts of response operations, showed that the limit is likely to be exceeded. Thus, our results show that chemical dispersants in realistic dosages could impact seabirds.

Climate change in the Arctic: Testing the poleward expansion of ticks and tick-borne diseases.

Climate change is most strongly felt in the polar regions of the world, with significant impacts on the species that live there. The arrival of parasites and pathogens from more temperate areas may become a significant problem for these populations, but current observations of parasite presence often lack a historical reference of prior absence. Observations in the high Arctic of the seabird tick Ixodes uriae suggested that this species expanded poleward in the last two decades in relation to climate change. As this tick can have a direct impact on the breeding success of its seabird hosts and vectors several pathogens, including Lyme disease spirochaetes, understanding its invasion dynamics is essential for predicting its impact on polar seabird populations. Here, we use population genetic data and host serology to test the hypothesis that I. uriae recently expanded into Svalbard. Both black-legged kittiwakes (Rissa tridactyla) and thick-billed murres (Uria lomvia) were sampled for ticks and blood in Kongsfjorden, Spitsbergen. Ticks were genotyped using microsatellite markers and population genetic analyses were performed using data from 14 reference populations from across the tick's northern distribution. In contrast to predictions, the Spitsbergen population showed high genetic diversity and significant differentiation from reference populations, suggesting long-term isolation. Host serology also demonstrated a high exposure rate to Lyme disease spirochaetes (Bbsl). Targeted PCR and sequencing confirmed the presence of Borrelia garinii in a Spitsbergen tick, demonstrating the presence of Lyme disease bacteria in the high Arctic for the first time. Taken together, results contradict the notion that I. uriae has recently expanded into the high Arctic. Rather, this tick has likely been present for some time, maintaining relatively high population sizes and an endemic transmission cycle of Bbsl. Close future observations of population infestation/infection rates will now be necessary to relate epidemiological changes to ongoing climate modifications.

Shifting environmental predictors of phenotypes under climate change: a case study of growth in high latitude seabirds

Climate change is altering species' traits across the globe. To predict future trait changes and understand the consequences of those changes, we need to know the environmental drivers of phenotypic change. In the present study, we use multi‐decadal long datasets to determine periods of within‐year environmental variation that predict growth of three seabird species. We evaluate whether these periods changed over time and use them to predict future growth under climate change. We find that predictions of trait change could be improved by considering that 1) the timing of environmental factors used to predict traits (predictive‐environmental features) can change over time, and 2) the type of predictive‐environmental features can change over time. We find evidence of changes in the timing of environmental predictors in all populations studied and evidence for a change in the type of predictor in the studied Arctic murre population. Environmental models of growth predict that warming conditions will decrease growth rates and bird body sizes in two species (black‐legged kittiwake Rissa tridactyla and glaucous‐winged gull Larus Larus glaucescens), but not the third (thick‐billed murre Uria lomvia). Consequently, climate change is likely to decrease fledging rates in the gulls and kittiwakes. Further, we find that sea ice‐cover historically predicted murre chick growth well, but no longer does – instead air temperature is now a better predictor of murre growth. Our study highlights a need to investigate whether environmental determinants of trait variation commonly shift in a changing climate and whether such changes have implications for adaptation to novel environments.

Re-establishment of an extinct breeding colony of Brünnich’s Guillemot Uria lomvia in West Greenland

The breeding population of Brünnich’s Guillemot Uria lomvia in South and West Greenland has been decreasing for decades and some colonies have even disappeared (Merkel et al. 2014). Among these was one of the largest colonies, Salleq in Uummannaq Fjord (70°96’N 52°25’W; Figure 1), which was estimated at half a million birds in c. 1920 (Bertelsen 1921) and 150,000 birds in 1949 (Salomonsen 1950). These figures are most likely overestimations (Falk &amp; Kampp 1997), but there is no doubt that the colony was among the largest in West Greenland. The colony then drastically decreased in size until 1975, when only 4,500 birds were counted (Falk &amp; Kampp 1997). In 1984, there were only 150 individuals present and all were observed on the water below the cliff. In 1987, 50 birds were observed on the cliff without evidence of breeding, and the site was completely deserted by 1990 (Evans &amp; Kampp 1991). The same fate was recorded for Black-legged Kittiwakes Rissa tridactyla (hereafter ‘Kittiwakes’) and Razorbills Alca torda. The former declined from around 10,000 pairs in 1949, to 800 nests in 1975 and to zero in 1994 (F. Salomonsen unpublished; Boertmann et al. 1996). Razorbills declined from a few pairs in 1949 and 1975 to zero in 1994 (Boertmann et al. 1996). However, no population changes have been recorded for the Northern Fulmars Fulmarus glacialis which breed in huge numbers on the cliff. The decline and extinction of the Salleq Brünnich’s Guillemot colony in the decades after the Second World War was primarily caused by excessive hunting during spring. Fleischer (1994), the former editor of a Greenlandic newspaper, described how in the 1930s it was common in spring, when sea ice still covered the waters, to camp below the Salleq cliff and hunt hundreds of Brünnich’s Guillemots in a day. This occurred every spring, and people would travel from afar to participate in this hunt. This high hunting pressure was reflected in a higher recovery rate of ringed birds from Salleq in comparison to colonies in other parts of West Greenland (Kampp 1991). Naturally, the colony could not sustain such hunting pressure across multiple decades, and eventually disappeared. Another factor impacting the Brünnich’s Guillemot populations in West Greenland was bycatch by an extensive offshore drift net fishery for Atlantic Salmon Salmo salar, which peaked around 1970 and stopped in 1976 (Falk &amp; Durinck 1991).

Re-establishment of an extinct breeding colony of Brünnich’s Guillemot Uria lomvia in West Greenland

Re-establishment of an extinct breeding colony of Brünnich’s Guillemot Uria lomvia in West Greenland

Trends in hepatic cadmium concentrations in marine bird species from the Canadian Arctic

Cadmium (Cd) is a trace element of toxicological concern that has been monitored in marine birds inhabiting the Canadian Arctic since 1975. Despite nearly 50 years of monitoring, research to date has largely evaluated single species, locations, or time points, and there is as of yet no holistic overview that jointly considers all available Cd data. We addressed this information gap by combining and analyzing most of the existing data on hepatic Cd concentrations in marine birds from the Canadian Arctic. Using data collected between 1975 and 2018 from eight seabird species from 12 Arctic breeding colonies, we examined temporal, spatial, and interspecific variation in hepatic Cd levels, and we evaluated possible drivers of marine bird Cd loads. Hepatic Cd concentrations ranged from 1.6 to 124 μg/g dry weight across species, and were highest in thick-billed murres (Uria lomvia) and king eiders (Somateria spectabilis), and lowest in black guillemots (Cepphus grylle), black-legged kittiwakes (Rissa tridactyla), and long-tailed ducks (Clangula hyemalis). All sites with multiple years of data showed interannual fluctuations in Cd, which were correlated with the North Atlantic Oscillation (NAO) index and with the previous year's June sea ice coverage, where marine birds exhibited higher Cd concentrations in positive NAO years and following years with lower sea ice coverage. Climate change is likely to shift the NAO to being more negative and to reduce sea ice coverage, and our results thus identify various ways by which climate change could alter Cd concentrations in marine birds in the Canadian Arctic. Understanding variations in marine bird contaminant burdens, and how these may be alters by other stressors such as climate change, is important for long-term marine bird conservation efforts.