This record contains a comprehensive synthesis of previously published highly branched isoprenoid (HBI) results, providing a quantitative spatial and temporal assessment of carbon partitioning within the Arctic marine ecosystem and validating estimates of sea-ice particulate organic carbon (iPOC) values as quantitative predictors of ice algal carbon in Arctic food webs.This publication was a collaborative effort with the following contributors: David Yurkowski (Fisheries and Oceans Canada), Lisa Loseto (Fisheries and Oceans Canada), Steve Ferguson (Fisheries and Oceans Canada), Bruno Rosenberg (Fisheries and Oceans Canada), C.W. Koch (Natural History Museum, London, UK; University of Maryland Center for Environmental Science, Maryland, US); T.A. Brown (Scottish Association for Marine Science, Oban, Scotland); R. Amiraux (Centre for Earth Observation Science, University of Manitoba, Canada); C. Ruiz-Gonzalez (Scottish Association for Marine Science, Oban, Scotland); M. Maccorquodale (Scottish Association for Marine Science, Oban, Scotland); G. Yunda-Guarin (Québec-Océan and Takuvik, Biology Department, Laval University, Canada); D. Kohlbach (Norwegian Polar Institute, Fram Centre, Tromsø, Norway); N.E. Hussey (Integrative Biology, University of Windsor, Ontario, Canada).

PURPOSE:This Archer fiord data is associated with a larger program ArcticCORE, which was created to fulfill knowledge gaps and develop long term protection in the extremely remote Tuvaijuittuq region. The main objectives of this expedition were to improve our comprehension of the key drivers for productive capacity, diversity and ecosystem structure in areas connected to Baffin Bay and Tuvaijuittuq, including Archer fiord.DESCRIPTION:ArcticCORE is a 5-year broader program aiming to characterize Tuvaijuittuq’s unique ecosystem and its influence and connectivity with the adjacent ecosystems to inform sustainable management and conservation initiatives in Tuvaijuittuq and the eastern Arctic. In an Arctic Ocean with rapidly declining sea ice, Tuvaijuittuq area retains the oldest and thickest sea ice, and can act as a refuge for ice-dependent species. This program aims to characterize the Arctic marine ecosystem and establish baseline measurements for future comparisons in the region. From 2023, water collection was carried out at four stations throughout Archer Fiord and analyzed for primary productivity, chlorophyll a, phytoplankton flow cytometry and phytoplankton taxonomy down to the lowest identifiable level. These data will contribute to a better understanding of the key drivers for productive capacity, diversity and ecosystem structure in Archer fiord. Characterization of these upstream areas are relevant for an ecosystem-based approach to fisheries management in Baffin Bay, a priority for DFO and an intrinsic part of mandated activities, as they influence the ecosystem and fisheries resources downstream.

PURPOSE:Given the paucity of information on Arctic char along western Hudson Bay, in 2018, Fisheries and Oceans Canada (DFO) hosted an Arctic char workshop in Rankin Inlet, Nunavut, bringing together local resource users, knowledge holders, and co-management groups (e.g., Hunters and Trappers Organizations, Regional Wildlife Organization) to identify and discuss community-based Arctic char research priorities across the Kivalliq region of Nunavut. Communities were especially interested in examining “what Arctic char were eating” and “why the colour of their muscle is different” along the western Hudson Bay coastline, and in the summer of 2018, a regional community-based Arctic char monitoring program was implemented across the region. DESCRIPTION:Climate-induced alterations to Arctic sea ice dynamics are influencing the availability and distribution of resources, and in turn, the nutrient and energy intake of opportunistic predators across the food web. These temporal changes in local prey communities likely influence the availability of carotenoid-rich prey types, as well as the foraging ecology of opportunistic predators that forage in the marine environment, such as anadromous Arctic char (Salvelinus alpinus). Despite its socioeconomic importance across its range, anadromous Arctic char foraging ecology and its influence on muscle pigmentation, particularly in relation to sea ice dynamics, remains understudied. Here, over two years (2021, 2022) with contrasting sea ice dynamics, we investigated the foraging ecology of anadromous Arctic char and its influence on their muscle pigmentation at a southern (Rankin Inlet) and northern (Naujaat) location along western Hudson Bay using a combination of stomach contents, stable isotopes (δ¹³C and δ¹⁵N), highly branched isoprenoids, carotenoid spectrophotometry, and a standard muscle colour scale (DSM SalmoFan). Spatiotemporal variation in Arctic char diet occurred, where Rankin Inlet Arctic char generally consumed more fish and phytoplankton-based carbon sources, occupied a higher trophic position, and displayed a similar isotopic niche breadth compared to Arctic char in Naujaat. Invertebrates were higher in carotenoid concentration than fishes, and in association with a more invertebrate-based diet, Arctic char in Naujaat contained higher muscle carotenoid concentrations (e.g., astaxanthin) compared to Rankin Inlet Arctic char in 2021. In 2022, however, muscle carotenoid concentrations in Naujaat and Rankin Inlet Arctic char were more similar, as the diet of Arctic char in both locations was largely fish-based despite muscle colour remaining redder in Naujaat Arctic char. Overall, the observed plastic foraging ecology of Arctic char highlights this species' ability to adjust to inter-annual variability in environmental changes, which then impacts their muscle carotenoid concentration. Such inter-annual variation in Arctic char foraging ecology is anticipated to increase with unpredictable climate-driven environmental changes in the region, which could therefore negatively affect local resource users over the long term, resulting in socioeconomic impacts across the Arctic.Collection/sampling methodology:Arctic char were collected by angling and gillnetting (5.5” mesh, regularly checked) between June and August in the estuarine and marine environments near the communities of Rankin Inlet and Naujaat, Nunavut. In 2021, Naujaat Arctic char were collected by community fishers as part of a community-based sampling program. Concurrently, invertebrate prey types were opportunistically collected in the vicinity of Arctic char sampling sites using a conical zooplankton net (200-μm mesh; 10-minute tows) or obtained fresh from Arctic char stomachs. Additionally, marine fishes were opportunistically collected by angling or obtained fresh from Arctic char stomachs over both years in Rankin Inlet, while samples from the Naujaat area were collected in 2018 and 2019.The Kivalliq Wildlife Board (Rankin Inlet, NU) and Arviq Hunters and Trappers Association (Naujaat, NU) each supported this community-formulated research project and assisted with sample collections throughout the duration of the project. We would like to recognize and thank Sonny Ittinuar (Kivalliq Wildlife Board/Rankin Inlet Local Resource User), Clayton Tartak (Kivalliq Wildlife Board), Vincent L’Herault (ArctiConnexion), and Gail Davoren (University of Manitoba MSc co-supervisor) for their participation in the project. We would also like to thank Sonny Ittinuar, Poisey (Adam) Alogut, John-El, Peter, Quassa, and Goretti Tinashlu, who assisted in field work. USE LIMITATION:To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.

This dataset presents the first comprehensive, high-resolution (10-meter) wetland inventory map covering the entire 32.2 million square kilometers of the Pan-Arctic region, of which 14 million square kilometers (43%) is terrestrial and 18.4 million square kilometers (57%) is marine. Generated through advanced Earth Observation and machine learning techniques, the map was produced using multi-year (2020–2022), multi-source satellite imagery—including Sentinel‑1, Sentinel‑2, and ALOS PALSAR‑2—as well as various environmental features such as elevation. Over 1,000 wetland polygons were analyzed using an object-based random forest classification workflow on the Google Earth Engine cloud platform, achieving an average overall classification accuracy of 89%.The mapping extent was defined according to the Arctic Council’s Conservation of Arctic Flora and Fauna (CAFF) boundary, resulting in the identification of 2,947,618 km² of wetlands, representing 20% of the land area within the Pan-Arctic region. This dataset establishes a consistent and authoritative baseline for pan-Arctic wetlands, leveraging the latest advances in Earth Observation, machine learning, and cloud computing. The Canadian Wetland Classification System was used and includes the major wetland classes: bog, fen, marsh, swamp, and water.The overall wetlands coverage by country within the CAFF boundary was: Canada (27%), United States of America (i.e., Alaska 39%), Finland (31%), Iceland (8%), Norway (17%), Sweden (26%), Kingdom of Denmark (i.e., Greenland 1%), and the Russian Federation (21%).​Development of this product was undertaken by Natural Resource Canada's Canada Centre for Mapping and Earth Observation and the Canadian Geospatial Data Infrastructure Division in collaboration with the Arctic Council’s CAFF biodiversity group, CAFF Wetland Experts Group, national organisations mandated to monitor wetlands, and Arctic National Mapping Agencies, and Canadian company C-CORE, integrating ground truth data collected from Alaska, Finland, Sweden, and the Kingdom of Denmark through partner agencies and digital image interpretation. More than 60,000 images (2020-2022), primarily covering summer periods, were processed to ensure robust results.This dataset provides essential baseline information for Earth Observation monitoring of climate change impacts and supports critical environmental surveillance for Arctic and remote northern communities.

Commercial and exploratory fisheries for Arctic Char, Salvelinus alpinus, provide significant economic opportunities for Nunavummiut in several Nunavut communities. Having an accurate understanding of the weight of the Arctic Char that are harvested is important for tracking harvest and for understanding how biological parameters may be changing over time as a result of exploitation and/or climactic and environmental changes. Unfortunately, most fish enter the processing plants as dressed (gills and viscera removed) and therefore conversion factors have to be applied to reconcile whole (round) weight from dressed weight. Here, we provide an updated conversion factor based on linear regression for Arctic Char from the Halokvik River (locally known as 30 Mile) near the community of Cambridge Bay. This conversion factor can be used moving forward as the Halokvik River continues to be commercially harvested.

Records of marine mammal sightings (N = 5,324) collected by ASOs and submitted to Fisheries and Oceans Canada (DFO) between 1979-2024, across three DFO regions: the Arctic, Newfoundland and Labrador, and the Maritimes. Methods for initial data compilation are provided in the associated technical report "Marine mammal records collected by the at-sea observer (ASO) program in Arctic, Newfoundland and Labrador, and Maritimes regions: a summary of challenges and opportunities for future research." Cite this data as: Feyrer, L.J., Colbourne, N., Lawson, J.W., Moors-Murphy, H.B., Ferguson, S. Dataset update to Marine mammal records collected by the At-Sea Observer program in Arctic, Newfoundland and Labrador and Maritimes regions. Published: February 2025. Ocean Ecosystems Science Division, Fisheries and Oceans Canada, Dartmouth, N.S.

In 2018, Fisheries and Oceans Canada initiated the Multidisciplinary Arctic Program (MAP) – Last Ice, the first ecosystem study of the poorly characterized region of Tuvaijuittuq, where multiyear ice still resides in the Arctic Ocean. The program MAP-Last Ice takes a coordinated approach to integrate the physical, biochemical, and ecological components of the sea ice-ocean connected ecosystem and its response to climate and ocean forcings. This program provides baseline ecological knowledge for Tuvaijuittuq and, in particular, for its unique multiyear ice ecosystem. The database provides baseline data on fatty acid composition and stable isotopes signatures of sea ice communities in multi- and first-year ice in Tuvaijuittuq. The data were collected during the 2018 spring field campaign of the MAP-Last Ice Program, offshore of Canadian Forces Station (CFS) Alert, in the Lincoln Sea.

In 2018, Fisheries and Oceans Canada initiated the Multidisciplinary Arctic Program (MAP) – Last Ice, the first ecosystem study of the poorly characterized region of the Lincoln Sea in the Marine Protected Area of Tuvaijuittuq, where multiyear ice still resides in the Arctic Ocean. MAP-Last Ice takes a coordinated approach to integrate the physical, biochemical, and ecological components of the sea ice-ocean connected ecosystem and its response to climate and ocean forcings. The cross-disciplinary program establishes baseline ecological knowledge for Tuvaijuittuq and, in particular, for its unique multiyear ice ecosystem. The database provides baseline data on the abundance of bacteria and viruses in multi- and first-year ice and in surface waters of the Lincoln Sea in Tuvaijuittuq, and their relation to bio-physical conditions. The data were collected during the 2018 spring field campaign of the MAP-Last Ice Program, at an ice camp offshore of Canadian Forces Station (CFS) Alert.

PURPOSE:The focus of this research is on changes in the distribution of killer whales in the Canadian Arctic, which is within the field of marine biogeography and marine megafauna. Our research details change in killer whale presence and ties it to changes in sea ice coverage. These are novel results, presenting trends in the arrival and departure dates of killer whales into the eastern Canadian Arctic for the first time. We go on to discuss the impacts of these changes on other aspects of Arctic ecosystems and how increasing in killer whale presence might affect other species and the management of those species in Canada. Killer whales are a widespread species of interest, especially in the Canadian Arctic as their presence is tied to multiple aspects of a region rapidly changing from the effects of climate change. DESCRIPTION:This study examines 20 years of killer whale (Orcinus orca) sightings in the eastern Canadian Arctic, drawing from a comprehensive sighting database spanning 1850-2023. Despite inherent biases favoring data collection near communities and coastal areas, spatiotemporal analyses reveal significant shifts in killer whale distribution linked to changing sea ice conditions. We developed a clustering metric representing the mean distance to the five nearest sightings and results show that killer whales are progressively moving away from historically high-use areas and that sighting locations are becoming more dispersed over time. A significant year × sea ice interaction indicates observations occur earlier during their arrival period at lower sea ice concentrations over time, suggesting that declining sea iceconcentration contributes to earlier arrival. Conversely, for departure periods, killer whales are observed farther south later in the year, likely linked to earlier freeze-up at higher latitudes, and are overall observed later into the year over time. This trend has led to a near doubling of their average presence from 26 days in 2002 to 48 days in 2023 (27 July to 13 September) reflecting an extended open-water season. These findings underscore the prolonged seasonal use of Arctic regions by killer whales, driven by diminishing sea ice and expanding openwater habitat. Such shifts highlight potential implications for Arctic marine ecosystems as killer whales increasingly overlap with endemic species.

Fisheries and Oceans Canada (DFO) conducts research and undertakes monitoring surveys of the marine and freshwater environment in support of sustainable fisheries, healthy aquatic ecosystems and living resources, and safe and effective marine services. In an effort to effectively inform and ensure Canadians feel engaged in the delivery of its science mandate, DFO produces Fieldnotes, an annual compendium of planned science field operations in the North Pacific and Arctic oceans, as well as in the coastal and interior waters of British Columbia and Yukon.