In place since fall 1994, the sentinel fisheries program is the result of a collaboration between Fisheries and Oceans Canada (DFO) and Quebec and Newfoundland commercial fishermen's associations. Under this program, contracts are awarded by tender to fishermen’s associations to carry out fishing activities according to scientific protocols developed by DFO. The main objective of this survey is to collect data that will be used to calculate abundance indices for various fish stocks, including cod, Greenland halibut, Atlantic halibut and rockfish. Description of mobile survey The mobile gear sentinel fisheries of the northern Gulf of St. Lawrence are conducted in the sub-division 3Pn and the divisions 4R, 4S and the northern part of the division 4T of the Northwest Atlantic Fisheries Organization (NAFO). This program follows a stratified random survey plan according to depth strata, NAFO divisions and the type of substrate at the bottom. A standard tow is 30 minutes long and made at a speed of 2.5 knots. The fishing gear is a 300 Star Balloon trawl mounted on a Rock Hopper footgear. The trawl mesh size is 145 mm with a liner of 40 mm in the codend. Unless conditions at sea compromise safety during fishing activity, a retaining cable must be used to standardize the horizontal opening between vessels and the various depths fished. Data are collected by observers at sea or by technicians. The data contained in this program are divided into 4 different projects. -The summer series, carried out during the month of July -The fall series, which covers the period from 1995 to 2002 -The winter series, to study the mixing between the different stocks -The CRP (Cod reproductive potential) series, which targets the reproductive potential. Data For each trait, the total catch is sorted and weighed for each species. The number of individuals caught for each unmeasured fish species is noted. Biological data such as length, weight (sampled, per individual, gonad, liver and stomach), age, sex and maturity migth then be collected on a subsample of many species such as Atlantic halibut, Greenland halibut, lumpfish and Atlantic cod, using a variety of protocols. The biological data are divided into 4 files: a “Metadata” file containing set information, a “Catches” file containing catches per set for fish taxa, a “Carbio” file containing biological and morphometric measurements per individual, a “Freql” file containing the length frequency of fish. The data collected as part of this program is available below. It is important to note, however, that 1) only traits deemed successful have been retained; 2) historical data may contain inaccuracies; 3) the most recent survey is not available for validation purposes.

PURPOSE: This study is part of a two-decade series of research aimed to provide a comprehensive synthesis of the effects of harvest and environmental change on fisheries in Great Bear Lake. The main objectives are to assess demographic traits and the current status of harvested species, with a focus on evaluating sustainable harvest levels of lake trout, a cold-adapted species with a relatively narrow thermal niche. As part of this research, trends in water quality and primary productivity are monitored to evaluate potential effects of change on fisheries. DESCRIPTION: Great Bear Lake, one of the largest lakes in North America, contains culturally and recreationally important fish species. Great Bear Lake is located in the sub-Arctic and Arctic Circle. As part of a two-decade series of research aimed to provide a comprehensive synthesis of the effects of harvest and environmental change on fisheries in Great Bear Lake, the main objectives of this study are to assess demographic traits and the current status of harvested species, with a focus on evaluating sustainable harvest levels of lake trout, a cold-adapted species with a relatively narrow thermal niche. As part of this research, trends in water quality and primary productivity are monitored to evaluate potential effects of change on fisheries. From 2021 to 2024, surface water temperature data was collected at depths of 0.1 to 1.0 meters using an RBR Maestro3 through partnered community-led and community/Fisheries and Oceans Canada/university partner collaborative sampling. The project has strong community involvement, including youth through the Guardian Program, to facilitate capacity building and community leadership in the long-term monitoring of Great Bear Lake fisheries and the aquatic ecosystem. This data is an extension of baseline data sets on water quality on the lake. These data will contribute to a better understanding cumulative impacts of climate change on the functioning of large northern lake ecosystems and provide a benchmark for monitoring further change. This data will be important for developing effective strategies for maintaining community-led aquatic monitoring and managing natural resources, particularly fish, which are expected to be increasingly important to communities with declines in other country foods such as caribou. We acknowledge the data were collected in the Sahtú Settlement Area and are made publicly available with the agreement of the Délı̨nę Renewable Resources Council (Délı̨nę Ɂehdzo Got’ı̨nę (Renewable Resources Council)). Collaborators include: the Community of Délı̨nę partners (data collection), Délı̨nę Renewable Resource Council, Sahtú Renewable Resource Board, and University of Manitoba. Community of Délı̨nę partners and field workers that participated in data collection include Chris Yukon, Archie Vital, Ted Mackienzo, Daniel Baton, Lloyd Baton, Simon Neyelle, and Stanley Ferdanan. Funding and logistical support was provided by: Northwest Territories Cumulative Impact Monitoring, Sahtú Renewable Resource Board, the Polar Continental Shelf Program and Fisheries and Oceans Canada.

This dataset provides projected sea surface temperature and salinity as well as projected ocean bottom temperature and salinity in the Northwest Atlantic under a high emission scenario Representative Concentration Pathway (RCP) 8.5. The results are generated by a North Atlantic Ocean-ice Downsling System (NAODS) that downscales the global Climate Change System Model Version 4 (CCSM4) output. NAODS couples 1/12-degree model for the northwest Atlantic with a 1/4-degree model for the North Atlantic (Han et al., 2025). Bi-decadal means are included for 1986-2005, 2006-2025, 2026-2045, 2046-2065, 2066-2085, and 2080-2099, respectively.

This study aimed to identify chemical components that could distinguish chemical mixtures in oil sands process-affected water (OSPW) from natural groundwater sources. Oil sands process-affected samples were collected from two different oil sands development tailing ponds, and natural groundwater samples were collected from both far-field (greater than one kilometer (>1km) down- or upstream from an oil sands development site), and near-field (less than 200 meters (<200m) from an oil sands development site) locations. Water samples were assessed by geochemistry, total naphthenic acid analysis, and synchronous fluorescence spectroscopy (SFS) identifying those samples with acid-extractable organics (AEO). Using electrospray ionization high resolution mass spectrometry as well as multidimensional gas chromatography time-of-flight mass spectrometry profiling allowed for differentiation of natural from OSPW sources through the measurement of O2 : O4 ion class ratios. AEO profiles from OSPW and groundwater samples adjacent to tailings ponds were similar, suggesting a common source. All data are a part subject of a publication containing method details, full QA/QC, interpretation, and conclusions: Frank, R. A., Roy, J. W., Bickerton, G., Rowland, S. J., Headley, J. V., Scarlett, A. G., West, C. E., Peru, K. M., Parrott, J. L., Conly, F. M., & Hewitt, L. M. (2014). Profiling oil sands mixtures from industrial developments and natural groundwaters for source identification. Environmental science & technology, 48(5), 2660–2670. doi.org/10.1021/es500131k Response to comment: Frank, R. A., Roy, J. W., Bickerton, G., Rowland, S. J., Headley, J. V., Scarlett, A. G., West, C. E., Peru, K. M., Parrott, J. L., Conly, F. M., & Hewitt, L. M. (2014). Response to Comment on "Profiling oil sands mixtures from industrial developments and natural groundwaters for source identification". Environmental science & technology, 48(18), 11015–11016. doi.org/10.1021/es504008z

PURPOSE: Scope the distribution of Smallmouth Bass in the Miramichi River Watershed using eDNA DESCRIPTION: This dataset contains the results of work undertaken from 2019 to 2024 to scope the extent of the spread of Smallmouth Bass in parts of the Miramichi River Watershed using an eDNA-based species-specific qPCR approach. USE LIMITATION: To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.

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.

Fisheries and Oceans Canada (DFO) conducts an annual summer multidisciplinary scientific survey with a bottom trawl in the Estuary and the northern Gulf of St. Lawrence since 1984. Over the years, this survey has been conducted on four vessels: the MV Lady Hammond (1984-1990), the CCGS Alfred Needler (1990-2005), the CCGS Teleost (2004-2021) and the CCGS Cabot (2022-current). It is important to note that the objectives, the methods used and the identification of the species during these surveys have improved over time in response to DFO requests and mandates. The data are therefore not directly comparable between these surveys. The specificities of the missions onboard the MV Lady Hammond are described below. Objectives: 1. Assess groundfish populations abundance and condition 2. Assess environmental conditions 3. Conduct a biodiversity inventory of benthic and demersal megafauna 4. Monitor the pelagic ecosystem 5. Collect samples for various research projects Survey description The survey covers the northern Gulf of St. Lawrence, that is the divisions 4R, 4S and the northern part of division 4T of the Northwest Atlantic Fisheries Organization (NAFO). A stratified random sampling strategy is used for this survey and the fishing gear used on the MV Lady Hammond is a bottom trawl Western IIA. Standard trawling tows last 30 minutes, starting from the time the trawl touches the sea floor. Towing speed is 3.5 knots. Data For each fishing tow, the catch is sorted and weighed by taxa; individuals are counted and biological data are collected on a sub-sample. For fish, crab and squid, size and weight are measured by individual and, for some species, sex, gonad maturity, and the weight of certain organs (stomach, liver, gonads) are also evaluated. The soft rays of the anal fin are counted for redfish and otoliths are collected for redfish and Atlantic cod. Invertebrates are weighted and counted (no individual measurements). The biological data are divided into 4 files: a “Metadata” file containing set information, a “Catches” file containing catches per set for fish taxa, a “Carbio” file containing biological and morphometric measurements per individual and a “Freql” file containing the length frequency of fish. It's important to note that this is raw data. Only sets considered successful are retained. In each set, all species are kept, with a few exceptions. For more information please contact the data management team (gddaiss-dmsaisb@dfo-mpo.gc.ca).

Summary The Quebec region of the Department of Fisheries and Oceans (DFO) is responsible for the assessment of several fish and invertebrate stocks exploited in the Estuary and the northern Gulf of St. Lawrence. The commercial catches sampling program is one of the sources of information used to complete these assessments. The data collected by this program, at wharf or at sea, offers among other things the advantage of a relatively large spatio-temporal coverage and provides some of the necessary knowledge to assess the demography and the structure of the exploited populations. This program is implemented by specialized DFO staff whose main mandate is to collect biological data on groundfish, pelagic fish and marine invertebrate species that are commercially exploited in the various marine communities. Data This dataset on the Atlantic halibut (Hippoglossus hippoglossus) includes the metadata, sample weight, fish length, the sex and the number of specimens measured. This dataset covers the period of 1995 to present. In order to protect the confidentiality of the sources, some informations (such as those concerning the vessel) have been excluded and others (such as the date of capture) have been simplified. Entries where there was only one vessel in a fishing area for a given year were also excluded. Further information including the fishing areas coordinates can be found by clicking on the «Atlantic and Arctic commercial fisheries» and «Fishing areas» links below.

PURPOSE: To record hourly water temperatures throughout the Margaree watershed. DESCRIPTION: The Department of Fisheries and Oceans (DFO) has been deploying water temperature monitoring equipment since spring 1993 in the Margaree River watershed. Coverage has changed throughout the time series and there is little documentation regarding equipment used. In recent years data have been collected using VEMCOs. USE LIMITATION: To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.

Summary The Quebec region of the Department of Fisheries and Oceans (DFO) is responsible for the assessment of several fish and invertebrate stocks exploited in the Estuary and the northern Gulf of St. Lawrence. The commercial catches sampling program is one of the sources of information used to complete these assessments. The data collected by this program, at wharf or at sea, offers among other things the advantage of a relatively large spatio-temporal coverage and provides some of the necessary knowledge to assess the demography and the structure of the exploited populations. This program is implemented by specialized DFO staff whose main mandate is to collect biological data on groundfish, pelagic fish and marine invertebrate species that are commercially exploited in the various marine communities. Data This dataset on the common softshell clam (Mya arenaria) includes the metadata, sample weight, the shell width and the number of specimens measured. This dataset covers the periods of 1994 and 2004-2010. In order to protect the confidentiality of the sources, some informations (such as those concerning the vessel) have been excluded and others (such as the date of capture) have been simplified. Entries where there was only one vessel in a fishing area for a given year were also excluded. Further information including the fishing areas coordinates can be found by clicking on the «Atlantic and Arctic commercial fisheries» and «Fishing areas» links below.