Andrew R. Majewski

• Researcher at Fisheries and Oceans Canada

The high Arctic shelves are the particularly understudied area of the Arctic. Climate change is predicted to cause increase in primary production with cascading effect on the Arctic ecosystems, and predicted increased ship traffic through the now-ice-free areas will create anthropogenic disturbance. Thus, understanding the high Arctic shelves is re...

Supplementary material for 'Cephalopod distribution and ecology over the high Arctic shelves in the Laptev, East-Siberian, and Beaufort seas'

This study investigated methylmercury (MeHg) concentrations in Arctic benthic invertebrates from two shelf sites in the Canadian Beaufort Sea. Carbon, nitrogen, and sulfur stable isotopes and fatty acids were measured to examine diet influences on MeHg concentrations in 476 individuals from 53 taxa of benthic invertebrates representing three differ...

Arctic cod (Boreogadus saida) is the most abundant forage fish species in Arctic seas and plays a pivotal role in the transfer of energy between zooplankton and top predators. The dominance of Arctic cod and the Arctic’s relatively low biodiversity interact such that changing population dynamics of Arctic cod have cascading effects on whole Arctic...

The Arctic cod (Boreogadus saida (Lepechin, 1774)) represents the most widespread and abundant fish in the Arctic and is a critical trophic link in its ecosystems. Like many species endemic to the region, it has lost essential habitat as the extent and thickness of sea ice have declined substantially in recent decades. Extreme warming induced by cl...

This study presents the first evidence that a diverse suite of phycotoxins is not only being actively produced by the toxigenic algal communities in the Canadian Arctic waters, but is also entering the marine food web. We detected measurable amounts of Amnesic Shellfish Toxins (ASTs) and Paralytic Shellfish Toxins (PSTs), as well as trace amounts o...

Passive acoustic monitoring is a powerful tool for observing soniferous species in remote marine environments over long periods of time, which can inform conservation planning and wildlife management. In this study, we collected seven months of passive acoustic data from early February to early September 2019 in Minto Inlet, Northwest Territories,...

Forage fish form a critical trophic link in marine ecosystems, and yet, for many species, there is limited information available. As nations move from single species stock assessments to ecosystem approaches to fisheries management (EAFMs), more information on forage fish will be required. In this study, 50 years of scientific literature were syste...

In the Arctic, climate-driven alterations to the quality and quantity of organic matter reaching the seafloor will likely affect benthic food web function. We used biomass-weighted diversity measures based on trophic traits (those related to feeding behaviours, e.g., mobility, size, food source), stable isotope ratios (δ¹⁵N and δ¹³C), and taxonomy...

As marine ecosystems respond to climate change and other stressors, it is necessary to evaluate current and past hybridization events to gain insight on the outcomes and drivers of such events. Ancestral introgression within the gadids has been suggested to allow cod to inhabit a variety of habitats. Little attention has been given to contemporary...

Understanding fish movement in the Arctic is paramount during the current era of rapidly warming seas, receding sea ice and associated shifting species distributions and fishing effort. We synthesized the literature and identified key knowledge gaps on the movement ecology of Arctic cod (Boreogadus saida) and Polar/Ice cod (Arctogadus glacialis, bo...

The eastern Beaufort Sea (EBS) beluga whale Delphinapterus leucas population has experienced a 20 yr decline in inferred growth rates of individuals, which is hypothesized to have resulted from changes in prey availability. We used fatty acid signatures and stable isotope ratios to reconstruct the proportional contributions of 14 prey species to th...

Previous work found that an earlier ice breakup favors the recruitment of juvenile polar cod (Boreogadus saida) by enabling early hatchers to survive and reach a large size by late summer thanks to a long growth season. We tested the hypothesis that, in addition to a long growth season, an earlier ice breakup provides superior feeding conditions fo...

Polar cod, Boreogadus saida, is an important part of Arctic and boreal marine ecosystems. Knowledge of polar cod population genetic structuring can provide insight into how the species may respond to environmental change, and allow for establishment of meaningful management units. To examine population genetic structure of B. saida, we analysed nin...

High-latitude fish typically exhibit a narrow thermal tolerance window, which may pose challenges when coping with temperatures that shift outside of a species’ range of tolerance. Due to its role in aerobic metabolism and energy balance, the mitochondrial genome is likely critical for the acclimation and adaptation to differing temperature regimes...

Overview and synthesis of the present state of the Arctic Seas of Canada

Specific case studies in support of the main technical report 3344

Understanding drivers of benthic-pelagic coupling in Arctic marine ecosystems is key to identifying benthic areas that may be sensitive to climate-driven changes in hydrography and surface production. We coupled algal biomass and sedimentary characteristics with stable isotope data for 113 fishes and invertebrates in the Canadian Beaufort Sea and A...

The Canadian Arctic is facing new issues with increased marine traffic, exploration and exploitation of resources. Knowledge of the environment is needed to address these issues. Fisheries and Oceans Canada conducted a survey during summers 2012 to 2014 in the Canadian Beaufort Sea and the Amundsen Gulf. The “BREA-MFP” Beaufort Regional Environment...

The Canadian Arctic is facing new issues with increased marine traffic, exploration and exploitation of resources. Knowledge of the environment is needed to address these issues. Fisheries and Oceans Canada conducted a survey during summers 2012 to 2014 in the Canadian Beaufort Sea and the Amundsen Gulf. The “BREA-MFP” Beaufort Regional Environment...

Climate change is expected to drive shifts in abundance and distribution of marine forage fishes and possibly result in dietary overlap among sub-Arctic and Arctic species. Stable isotopes of carbon and nitrogen (δ13C, δ15N) were used as a proxy of dietary niche breadth and overlap between co-occurring, immature capelin (Mallotus villosus) and pola...

Trophic patterns for Greenland Halibut are reported for the first time in the Canadian Beaufort Sea and Amundsen Gulf (n = 269). Samples were collected from 2012 to 2014 on the upper (300–500 m) and lower continental slope (750–1500 m) and were analyzed for stomach contents, stable isotopes ratios and fatty acids (FA). Stomach contents indicated th...

Polar cod (Boreogadus saida) is one of the most studied Arctic marine fishes given its circumpolar distribution and centralised role in the Arctic marine food web. In contrast, relatively little is known about two other Arctic Gadidae: saffron cod (Eleginus gracilis) and Greenland cod (Gadus ogac). Climate change is expected to have an effect on se...

Accumulation of trimethylamine N-oxide (TMAO) by deep-sea animals is proposed to protect proteins against the destabilizing effects of high hydrostatic pressure (the piezolyte hypothesis). Chondrichthyan fishes (sharks, rays, and chimaeras) provide a unique test of this hypothesis because shallow-living species have elevated TMAO levels to countera...

Polar cod (Boreogadus saida) is the dominant forage fish in Arctic seas and the main prey of the ringed seal (Pusa hispida), the beluga (Delphinapterus leucas) and several seabird species. Changes in the abundance of polar cod will have cascading effects on arctic marine ecosystems. We tested the hypothesis that an earlier sea ice breakup and warme...

This report presents stable isotope data (δ15N, δ13C and C:N ratios) for marine fishes, benthic invertebrates, zooplankton and sediments collected as part of the Beaufort Regional Environmental Assessment Marine Fishes Project. Sampling was conducted along 12 transects in the Canadian Beaufort Sea and Amundsen Gulf during the open water seasons of...

The Northwest Territories (NWT) is home to a diverse group of plants and animals. About 30,000 species are estimated to occur here. An important first step in safeguarding biodiversity is to increase our knowledge of each species and to provide a mechanism to monitor the conservation status of each species regularly. Monitoring the status ranks of...

Marine fishes in the Canadian Beaufort Sea have complex interactions with habitats and prey, and occupy a pivotal position in the foodweb by transferring energy between lower- and upper-trophic levels, and also within and among habitats (e.g., benthic-pelagic coupling). The distributions, habitat associations, and community structure of most Beaufo...

Trophic ecology of most demersal Arctic fishes remains one of the major knowledge gaps for understanding food web dynamics and connectivity among ecosystems. In this study, fatty acids (FA) and stable isotopes (SI) were used to study the feeding ecology of seven species (n = 106) of the most abundant benthic fishes (eelpouts, sculpins and agonids)...

The Beaufort Sea Marine Fishes Project (BSMFP) was developed as a multistakeholder initiative aimed to address information gaps for deep-water fish communities relevant to the regulatory review, assessment, and management of offshore oil and gas exploration and development in the Canadian Beaufort Sea. The BSMFP provides important basic knowledge a...

The offshore marine ecosystem of the Canadian Beaufort Sea faces the double pressure of climate change and industrialization. Polar cod (Boreogadus saida) is a pivotal forage species in this ecosystem, accounting for 95 % of the pelagic fish assemblage. Its vertical distribution over the annual cycle remains poorly documented. Hydroacoustic records...

Reduction in sea ice due to climate change is expected to have a negative impact on habitat availability for Arctic marine fishes and induce range expansion of species from southern environments. Such an effect will likely be observed in the abundance of polar cod, Bore- ogadus saida (Lepechin, 1774), as well as interspecific interactions of this i...

Arctic Cod (Boreogadus saida) occur throughout the circumpolar north; however, their distributions at localized scales are not well understood. The seasonal habitat associations and diet preferences across life-history stages of this keystone species are also poorly known, thereby impeding effective regulatory efforts in support of conservation obj...

The quality and quantity of food reaching the seafloor is negatively related to water column depth. Lower food availability at depth may in turn affect trophic structure and result in depth-related patterns in biomass and body size (size spectra) in demersal fish communities. Here, we used demersal fish collected from four habitat depths in the Bea...

The BSMF project was developed as a multi-stakeholder initiative aimed to address information gaps for deep-water fish communities relevant to the regulatory review, assessment, and management of offshore oil and gas exploration and development in the Canadian Beaufort Sea. The BSMF project provides important basic knowledge as to what species are...

Hierarchical cluster analysis of Arctic Cod (Boreogadus saida) gut content samples. Solid lines indicate groupings that are statistically different at α = 0.05

In 2012, Arctic cod (Boreogadus saida) were collected from offshore regions of the Beaufort Sea to determine the concentrations of CYP1A1 phase I metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) in liver and to correlate measured concentrations with (i) morphometric measurements that are known to be indicative of fish health and, (ii) bioc...

A proposal to conduct offshore exploratory drilling in the Beaufort Sea prompted an investigation of the biophysical conditions that prevail in the area during the winter. The drilling was to be conducted at the Paktoa site, approximately 50 km North East of Garry Island in the Mackenzie Delta, Northwest Territories, using a steel drilling caisson...

Distribution and diet of bottom-dwelling Arctic cod were studied in the nearshore Canadian Beaufort Sea in summer of 2006–2009 using a 3 m benthic beam trawl. In total, 82 stations were visited ranging in depth from 8 to 128 m. Fish densities were generally low for benthic habitats; pelagic fish occurrence was not assessed. We observed a gradual in...

This study examines the community structure of demersal marine fishes on the Canadian Beaufort Shelf and at Herschel Island, Yukon Territory. Fishes were sampled along five transects during the summers of 2006–2009 to assess community structure. Environmental parameters were documented to examine habitat associations of fishes. Results indicate a s...

The data set is composed of raw files recorded with a SIMRAD EK60 three-frequency (38, 120, 200 kHz) split-beam echosounder that was operated continuously during the 2012, 2013, and 2014 BREA cruise aboard the F/V Frosti. This entry also includes EK60 data collected during the ArcticNet cruise aboard the CCGS Amundsen in 2014. All three 7° transduc...

An Area of Interest (AOI) in Darnley Bay of the western Canadian Arctic is being considered for designation as a Marine Protected Area (MPA) under the Oceans Act. The AOI was nominated based on the presence of two Ecologically and Biologically Significant Areas (EBSAs). Under the Health of the Oceans Initiative, Fisheries and Oceans Canada (DFO) Sc...

Biological sampling was conducted along five transects, and 13 additional stations, within the Canadian Beaufort Sea between July 23rd and August 16th, 2008, as part of the Northern Coastal Marine Studies program. Fishing was conducted at 33 stations using a benthic trawl. The objective of this study was to contribute to the biological and ecologic...

Biological sampling was conducted along five transects, and six additional stations, within the Canadian Beaufort Sea between July 31st and August 12th, 2007, as part of the Northern Coastal Marine Studies program. Fishing was conducted using either a benthic trawl or gill nets. The objective of this study was to improve our understanding of the bi...

Biological sampling was conducted along two transects, and two additional stations, within the Canadian Beaufort Sea between July 29th and August 14th, 2005, as part of the Northern Coastal Marine Studies program. Fishing was conducted at 17 stations using a combination of mid-water trawling and multi-mesh gill nets. Fish were also collected as by-...

Biological sampling was conducted along two transects, and two additional stations, within the Canadian Beaufort Sea between August 1-12, 2006, as part of the Northern Coastal Marine Studies program. Fishing was conducted at 17 stations using a combination of mid-water trawling and benthic trawling. The objective of this study was to contribute to...

Mercury (Hg) concentrations in fish in boreal reservoirs have been shown to be increased for up to 3 decades after impoundment. However, the time course of increased concentrations is not well known. The purpose of this study was to determine the evolution of Hg concentrations in fish in the boreal reservoirs of northern Manitoba, Canada, and its r...

Large volumes of water are required by industry in the Northwest Territories (NWT) to conduct activities such as hydrocarbon exploration and winter road construction. Fish living in small lakes are particularly sensitive in late winter due to limited oxygen supplies. These oxygen supplies can be further reduced to harmful levels through winter wate...

Hydroelectricity is considered a relatively clean source of power, but flooding forests to create reservoirs can generate greenhouse gas emissions and accelerate mercury accumulation. For that reason, a scientific understanding of the environmental effects associated with this practice is important, say R. A. Bodaly, Kenneth G. Beaty, Len H. Hendze...

For the past 9 years, we experimentally flooded a wetland complex (peatland surrounding an open water pond) at the Experimental Lakes Area (ELA), northwestern Ontario, Canada, to examine the biogeochemical cycling of methyl mercury (MeHg) in reservoirs. Using input-output budgets, we found that prior to flooding, the wetland complex was a net sourc...

Among fishes, courtship behaviour and nesting defense are strong predictors of reproductive success. We conducted three experiments to assess the impacts of exposure to 17α-ethynylestradiol (EE2) on the ability of male fathead minnows (Pimephales promelas) to establish and defend a spawning territory. Fish were exposed to EE2 (2 or 8 ng L-1) for 27...

Among fishes, courtship behaviour and nesting defense are strong predictors of reproductive success. We conducted three experiments to assess the impacts of exposure to 17alpha-ethynylestradiol (EE2) on the ability of male fathead minnows (Pimephales promelas) to establish and defend a spawning territory. Fish were exposed to EE2 (2 or 8 ng L(-1))...