Factors and mechanisms driving among-lake variability of mercury concentrations in a benthivorous fish in the Canadian subarctic.

Wild-caught fish are an important subsistence food source in remote northern regions, but they can also be a source of exposure to mercury (Hg), which has known health hazards. We investigated factors and mechanisms that control variability of Hg concentrations in Lake Whitefish (Coregonus clupeaformis) among remote subarctic lakes in Northwest Territories, Canada. Integrating variables that reflect fish ecology, in-lake conditions, and catchment attributes, we aimed to not only determine factors that best explain among-lake variability of fish Hg, but also to provide a whole-ecosystem understanding of interactions that drive among-lake variability of fish Hg.

Harvester selection and observed mercury levels in Eastern Beaufort Sea and Western Hudson Bay beluga whales (Delphinapterus leucas).

Mercury in marine biota has been extensively studied across Inuit Nunaat because it bioaccumulates and biomagnifies in high trophic level species, such as the beluga whale (Delphinapterus leucas), or qilalugaq in Inuktut. Qilalugaait (pl) are a staple in many coastal Inuit communities, including Tuktoyaktuk, Northwest Territories and Arviat, Nunavut. We examine how total mercury (THg) concentrations in two beluga populations are influenced by biased sampling resulting from local harvester preferences.

Can remotely sensed catchment to lake area ratios predict mercury levels in subarctic fishes?

Mercury concentrations ([Hg]) in fish reflect a complex array of interacting biogeochemical and ecological variables. In northern regions where fish are a critical subsistence food, understanding and predicting fish [Hg] can be particularly difficult, largely due to a paucity of comprehensive data associated with the logistical challenges of field sampling. Building on previous work where we elucidated causal relationships between fish [Hg] and a variety of catchment, water quality, and ecological variables in subarctic lakes, we investigated whether using only ratios of catchment area to lake area (CA:LA) can predict [Hg] in northern freshwater fish species.

Gill raker and pyloric caeca counts differ between Arctic char (Salvelinus alpinus) and Dolly Varden (S. malma) populations across their ranges.

Meristic characters are often used to differentiate between closely related forms, morphs, and species of fishes, and lend insight into ecology and post-glacial recolonization in taxa with complicated or contentious phylogenies, including the genus Salvelinus. Previous studies of meristics in Salvelinus have focused mostly on individual populations. We collated data from 456 populations/systems across the North American and Russian Arctic and sub-Arctic, and found that counts of pyloric caeca and gill rakers differed consistently between fish visually and/or genetically identified as Arctic char and Dolly Varden across their distributional ranges.

Migration timing and marine space use of an anadromous Arctic fish (Arctic Char, Salvelinus alpinus) revealed by local spatial statistics and network analysis.

Background: The ice-free season (typically late-June to early-October) is crucial for anadromous species of fish in the Arctic, including Arctic Char (Salvelinus alpinus), which must acquire adequate resources for growth, reproduction, and survival during a brief period of feeding in the marine environment. Arctic Char is an important food fish for Inuit communities across the Arctic. Understanding drivers and patterns of migration in the marine environment is thus essential for conservation and management of the species.

Mercury bioaccessiblity in freshwater fish species from northern Canada.

Indigenous communities in northern Canada rely on locally harvested traditional foods, including fish, which provides them with nutritional, cultural, and social benefits. However, mercury exposure from fish consumption can pose a health risk for populations that consume large amounts of fish with elevated mercury concentrations. The bioaccessiblity of mercury in the tissue of northern Canadian freshwater fish is not yet known.

Mercury concentrations decline with age in the fur of females of an insectivorous terrestrial mammal (Myotis lucifugus).

Methylmercury (MeHg) is a toxic form of mercury that bioaccumulates in organisms and biomagnifies through food webs. MeHg concentrations can be high in aquatic environments, and this puts high trophic-level predators who derive energy originating from aquatic environments at risk of toxic effects. Due to the potential for bioaccumulation of MeHg over an individual's life, the risk of MeHg toxicity may increase as animals age, and this risk may be especially high in species with relatively high metabolic rates.

Investigating effects of climate-induced changes in water temperature and diet on mercury concentrations in an Arctic freshwater forage fish.

The amount of mercury (Hg) in Arctic lake food webs is, and will continue to be, affected by rapid, ongoing climate change. At warmer temperatures, fish require more energy to sustain growth; changes in their metabolic rates and consuming prey with potentially higher Hg concentrations could result in increased Hg accumulation. To examine the potential implications of climate warming on forage fish Hg accumulation in Arctic lakes, we quantified growth and Hg accumulation in Ninespine Stickleback Pungitius pungitius under different temperature and diet scenarios using bioenergetics models.

Estimates, spatial variability, and environmental drivers of mercury biomagnification rates through lake food webs in the Canadian subarctic.

Biomagnification of mercury (Hg) through lake food webs is understudied in rapidly changing northern regions, where wild-caught subsistence fish are critical to food security. We investigated estimates and among-lake variability of Hg biomagnification rates (BMR), relationships between Hg BMR and Hg levels in subsistence fish, and environmental drivers of Hg BMR in ten remote subarctic lakes in Northwest Territories, Canada. Lake-specific linear regressions between Hg concentrations (total Hg ([THg]) in fish and methyl Hg ([MeHg]) in primary consumers) and baseline-adjusted δN ratios were significant (p < 0.

Contributions and perspectives of Indigenous Peoples to the study of mercury in the Arctic.

Arctic Indigenous Peoples are among the most exposed humans when it comes to foodborne mercury (Hg). In response, Hg monitoring and research have been on-going in the circumpolar Arctic since about 1991; this work has been mainly possible through the involvement of Arctic Indigenous Peoples. The present overview was initially conducted in the context of a broader assessment of Hg research organized by the Arctic Monitoring and Assessment Programme.

Mercury biomagnification in benthic, pelagic, and benthopelagic food webs in an Arctic marine ecosystem.

Mercury (Hg) is a ubiquitous toxic metal that biomagnifies in food webs, and can reach high concentrations in top predators. Evaluating Hg biomagnification in Arctic marine food webs is critical for understanding Hg dynamics and estimating exposure to understudied fish and wildlife consumed by humans. The majority of studies conducted on Hg biomagnification in the Arctic have focused on pelagic food webs.

Molecular Classes and Growth Hormone Treatment Effects on Behavior and Emotion in Patients with Prader-Willi Syndrome.

Prader-Willi syndrome (PWS) is a complex genetic disorder with three genetic classes. Patients with PWS are characterized by severe hypotonia, developmental delay, behavioral problems, learning disabilities and morbid obesity in early childhood if untreated. Data were collected through Rare Disease Clinical Research Network (RDCRN) from four study centers which evaluated patients with PWS.

Overwintering ecology and movement of anadromous Arctic char (Salvelinus alpinus) in a large, ice-covered river in the Canadian Arctic.

Arctic char (Salvelinus alpinus) is a facultatively anadromous fish species that is critically important to many Inuit communities in the Canadian Arctic. Plasticity in life history has allowed the species to persist in a diversity of challenging Holarctic environments. Despite their ecological and cultural importance and their presence in aquatic ecosystems that are ice-covered for much of the year, few under-ice studies of Arctic char have been conducted.

A meta-collection of nitrogen stable isotope data measured in Arctic marine organisms from the Canadian Beaufort Sea, 1983-2013.

Objectives: Existing information on Arctic marine food web structure is fragmented. Integrating data across research programs is an important strategy for building a baseline understanding of food web structure and function in many Arctic regions. Naturally-occurring stable isotope ratios of nitrogen (δN) and carbon (δC) measured directly in the tissues of organisms are a commonly-employed method for estimating food web structure.

Hair to blood mercury concentration ratios and a retrospective hair segmental mercury analysis in the Northwest Territories, Canada.

Concentrations of total mercury were measured in blood and hair samples collected as part of a human biomonitoring project conducted in First Nations communities of the Mackenzie Valley, Northwest Territories, Canada. Hair (n = 443) and blood (n = 276) samples were obtained from six communities in the Dehcho region and three communities in the Sahtú region of the Mackenzie Valley. The aim of this paper was to calculate hair to blood mercury ratios (for matched samples) and determine if: 1) ratios differed significantly between the two regions; 2) ratios differed from the 250:1 ratio proposed by the WHO; and, 3) point estimates of hair to blood mercury ratios could be used to estimate blood mercury concentrations.

David W. Schindler (1940-2021).

A world-renowned scientist who combined his formidable intellect with passionate advocacy to address problems affecting global freshwaters and the people who rely on them, while empowering generations of diverse peoples to action.

Anadromy and marine habitat use of Lake trout (Salvelinus namaycush) from the central Canadian Arctic.

Anadromy was documented in 16 lake trout, Salvelinus namaycush, from Canada's central Arctic using capture data and otolith microchemistry. For the first time, estuarine/marine habitat use was described for five individuals using acoustic telemetry. Age-at-first-migration to sea was variable (10-39 years) among individuals and most S.

Screening-level risk assessment of methylmercury for non-anadromous Arctic char (Salvelinus alpinus).

Non-anadromous forms of Arctic char (Salvelinus alpinus), those that are restricted to lakes and rivers, typically have higher mercury (Hg) concentrations than anadromous forms, which migrate to and from the sea. Using tissue burden data from the literature and our own analyses, we performed a screening-level risk assessment of methylmercury (MeHg) for non-anadromous Arctic char. Our assessment included 1569 fish distributed across 83 sites.

Design of a human biomonitoring community-based project in the Northwest Territories Mackenzie Valley, Canada, to investigate the links between nutrition, contaminants and country foods.

Community-based projects place emphasis on a collaborative approach and facilitate research among Indigenous populations regarding local issues and challenges, such as traditional foods consumption, climate change and health safety. Country foods (locally harvested fish, game birds, land animals and plants), which contribute to improved food security, can also be a primary route of contaminant exposure among populations in remote regions. A community-based project was launched in the Dehcho and Sahtù regions of the Northwest Territories (Canada) to: 1) assess contaminants exposure and nutrition status; 2) investigate the role of country food on nutrient and contaminant levels and 3) understand the determinants of message perception on this issue.

Mercury and omega-3 fatty acid profiles in freshwater fish of the Dehcho Region, Northwest Territories: Informing risk benefit assessments.

Traditional foods have significant nutritional, sociocultural and economic value in subarctic First Nations communities of the Northwest Territories, and play a crucial role in promoting cultural continuity and sovereignty. Omega-3 polyunsaturated fatty acids (N-3 PUFAs), including eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), carry significant benefits for neurocognitive development and cardiovascular health. However, the health risks posed by methylmercury may serve to undermine the benefits of fish consumption in Northern Indigenous communities.

Associations between omega-3 fatty acids, selenium content, and mercury levels in wild-harvested fish from the Dehcho Region, Northwest Territories, Canada.

To better understand the risks and benefits of eating wild-harvested fish from the Northwest Territories, Canada, levels of total mercury (HgT) and selenium (Se) and composition of omega-3 fatty acid (n-3 FA) were measured in muscle tissue of fish harvested from lakes in the Dehcho Region, Northwest Territories, Canada. Average HgT levels ranged from 0.057 mg/kg (cisco) to 0.

Distress tolerance is linked to unhealthy eating through pain catastrophizing.

Low distress tolerance, an important component of emotion regulation, is a risk factor for unhealthy eating. Identifying factors which explain the link between distress tolerance and unhealthy eating can advance the understanding of problematic eating and inform prevention and treatment of obesity and eating disorders. The present study examines pain catastrophizing as a mediator between distress tolerance and unhealthy eating in a nonclinical population, which has received little attention despite being a risk factor for unhealthy eating behaviors.

A new probabilistic method for quantifying n-dimensional ecological niches and niche overlap.

Considerable progress has been made in the development of statistical tools to quantify trophic relationships using stable isotope ratios, including tools that address size and overlap of isotopic niches. We build upon recent progress and propose a new probabilistic method for determining niche region and pairwise niche overlap that can be extended beyond two dimensions, provides directional estimates of niche overlap, accounts for species-specific distributions in niche space, and, unlike geometric methods, produces consistent and unique bivariate projections of multivariate data. We define the niche region (NR) as a given 95% (or user-defined a) probability region in multivariate space.