PURPOSE: To provide access to detailed stomach content data and associated metadata from Atlantic Bluefin Tuna sampled in the southern Gulf of St. Lawrence from 2018 to 2023. These data support fisheries science by contributing to analyses of predator–prey dynamics, diet composition, and ecosystem understanding, as well as informing stock assessment and fisheries management activities within Fisheries and Oceans Canada. DESCRIPTION: This dataset contains metadata and stomach content information collected from Atlantic Bluefin Tuna (ABFT) caught from mid-August to late September in the commercial fishery in the southern Gulf of St. Lawrence between 2018 and 2023. Stomach samples were primarily obtained from fish harvested near the eastern end of Prince Edward Island, with additional samples collected from the Miscou/Baie‑des‑Chaleurs area in 2018 and 2019. SAMPLING METHODS: Fish were measured to the nearest curved fork length (cm) and weighed to the nearest round weight (kg). Stomachs were obtained directly from harvesters or through a fish buyer and were stored at −20 ◦C before being processed in the laboratory. Stomachs identification numbers were cross-referenced with ABFT tag numbers recorded by fish provider in order to obtain logbook and port data (catch location, time, weight length, sex, gear, etc.) for each sample. Stomachs were thawed in the laboratory and the content was sorted and identified to the lowest possible taxonomic level. For each stomach, prey were weighed collectively as a taxonomic group and individually to the nearest 0.1 g. Dead bait used to capture ABFT, identified by cut marks, were recorded and weighed but excluded from the analysis. Live bait items cannot be identified from stomach content analyses. Only a few otoliths were found in 2018 and their degraded quality precluded performing ageing or species identification. Rare and small prey items such as algae and rocks were classified in the category “other”. Fish remains that could not be identified were classified in the category “Unidentified teleostei remains”. For 2019 to 2023, when stomach content items could not be visually identified and when tissue was available, tissue samples were collected and stored at −20 °C for DNA barcoding analysis. DNA extraction, mitochondrial cytochrome oxidase subunit 1 amplification, Sanger sequencing and species assignation were performed at the Plateforme d’Analyses Génomiques and Plateforme Bio-informatique of the Institut de Biologie Intégrative et des Systèmes (PAG-IBIS, Université Laval, Quebec city, QC, Canada, http://www.ibis.ulaval.ca/en/services-2/genomic-analysis-platform/). DNA was extracted from 20 mg of muscle tissue using the Omega Bio-tek E-Z-96 Tissue DNA Kit (Omega Bio-tek, Norcross GA, USA) following manufacturer instructions. The mitochondrial cytochrome oxidase subunit 1 region was amplified and sequenced as described in Hashemzadeh Segherloo et al., 2021). Sanger forward and reverse reads were analyzed independently using the Basic Local Alignment Search Tool against non-redundant sequences to identify the top hit for each sequence. When samples could not be identified by a top hit sequence they were classified as “unidentifiable fish”. Prey items that were successfully identified using DNA barcoding were incorporated into the stomach content analysis database and used in all subsequent diet analyses (abundance, occurrence and weight). The weight of the items used in the database was the weight of the remains as they were, and not reconstructed weights calculated for a live animal of the species identified by the barcoding. 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 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.

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 rock crab (Cancer irroratus) includes the metadata, sample weight, shell width, shell condition and the sex of the specimens measured. This dataset covers the periods of 1990 and 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: These data have been updated following a Canadian Science Advice Secretariat (CSAS) Regional Science Advisory Process. Associated publications are available in the citation section below or will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available. The dataset supports stock assessment by providing estimates of total returns of large and small Atlantic salmon to each Salmon Fishing Area (SFA) from 15 to 18, as well as to Gulf region rivers overall. DESCRIPTION: This dataset contains annual estimates of total returns of large and small Atlantic salmon to Salmon Fishing Areas (SFAs) 15 to 18 and to Gulf region rivers, as part of the stock assessment process up to the year 2022. 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.

Fisheries and Oceans Canada (DFO) conducted a winter multidisciplinary scientific surveys with a bottom trawl in the northern Gulf of St. Lawrence and Cabot Straight from 1978 to 1994. The specificities of the missions onboard the MV Gadus Atlantica 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. Collect samples for various research projects Survey description This winter survey covers the northern Gulf of St. Lawrence, that is the divisions 4R, 4S and 3Pn 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 Gadus Atlantica is an Engel 145 Otter trawl. 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 subsample. 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 Greenland halibut and Atlantic cod. Invertebrates are weighted and counted (no individual measurements). The biological data are divided into 4 files: a “Stations” file containing set information, a “Catches” file containing catches per set for all species caught, a “Carbio” file containing biological and morphometric measurements per individual, and a “Freql” file containing the length frequency of fish. The columns source_info, no_survey, nbpc and station_number serve as a common key linking the four datasets. To further link the “Captures” and the “Carbio” files to the species level (for fish and certain invertebrate species), use the columns source_info, no_survey, nbpc, station_number, strap_code, and category. Data collection methods and sampling protocols have varied over the years. These changes may affect the comparability of the data across sampling periods. For more information about the protocols used, please contact the data management team (gddaiss-dmsaisb@dfo-mpo.gc.ca). 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).

This dataset supports the assessment of plankton community structure and water quality within Toronto Area of Concern (AOC). The data was collected to evaluate the Beneficial Use Impairment (BUI) 13 - Degradation of Phytoplankton and Zooplankton Populations, and to provide georeferenced habitat information relevant to BUI 14 - Loss of Fish and Wildlife Habitat. The dataset provides a complete suite of water quality, microbial, phytoplankton and zooplankton observations collected from multiple georeferenced stations throughout the Toronto Harbor. Each datapoint includes latitude and longitude, sampling date, year and season, along with physiochemical measurements such as temperature, dissolved oxygen, total phosphorus, total nitrogen, nitrate + nitrite, chlorophyll-a and turbidity. Biological data includes phytoplankton, zooplankton and rotifer abundance and biomass across major taxonomic groups, as well as size structured zooplankton data distinguishing small and large taxa. The dataset also includes microbial community metrics and rate-based parameters such as bacterial growth rates, primary productivity and bacterial production. Sampling was conducted across multiple ecotypes identified by “Area” in the dataset (Inner Harbor, Islands, Habitat Cells and Embayments). The data structure allows for comparisons among sites, seasons, ecotypes and provides the basis for statistical analysis of plankton community composition, trophic relationships and ecological patterns within the AOC of Toronto Harbor. Results indicate water quality, zooplankton abundance and biomass differed across habitat ecotypes, with Inner Harbor exhibiting very low biomass similar to the open waters of Lake Ontario and a higher proportion of small taxa like rotifers, in spite of elevated nutrients. This pattern suggests environmental stress from runoff and contamination from the surrounding urban area. Zooplankton prey reductions are likely due to multiple urban environmental impacts including runoff and contaminants. Ecotype impacted zooplankton productivity but not primary productivity, indicating that protected systems (Island channels, Habitat Cells and Embayments) can offer diverse physical habitats and forage for fishes. Though primary productivity rates were reduced in most habitats, productivity was shunted into bacterial growth which were highly elevated throughout the entire AOC.

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 mackerel (Scomber scombrus) includes the metadata, sample weight, fish length, the sex and the number of specimens measured. This dataset covers the periods of 1976-1977 and 1984 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.

A research survey on snow crab (Chionoecetes opilio) was conducted on the Lower North Shore of the Gulf of St. Lawrence between Havre-Saint-Pierre and Blanc-Sablon in 2018, 2022 and 2024. The main objective of this survey was to assess the abundance of snow crab and species associated with snow crab habitat. Only data for benthic and demersal species associated with snow crab habitat are presented in this dataset. Data were collected according to a fixed station sampling design. A total of of 62 stations were sampled in 2018, 54 in 2022, and 46 in 2024, between 45 and 250 meters depth. Specimens were collected using a beam trawl with a total width of 2.8 meters and a total height of 0.76 meters. The codend was lined with a 16-17 millimeter stretched mesh net in order to harvest the small individuals. The hauls were made at a target speed of 2 knots and a target duration of 10 minutes depending on seabed conditions. Start and end positions were recorded to calculate the distance traveled on each tow using the geosphere library in R. The area covered at each tow was the product of the trawl opening and the distance traveled. The two files provided (DarwinCore format) are complementary and are linked by the "eventID" key. The "Activity_Information" file includes generic activity information, including date and location. The "occurrence_taxon" file includes the taxonomy of the species observed, identified to the species or lowest possible taxonomic level. For quality controls, all taxonomic names were checked against the World Register of Marine Species (WoRMS) to match recognized standards. All sampling locations were spatially validated. Abundance and density data for crabs under different size classes are available in a joint publication https://open.canada.ca/data/en/dataset/814e48c9-2dc7-4526-bd37-a4a120d66d6e

The contaminants in fish database is a compilation of contaminant data analysed from fish tissue at the Fresh Water Institute from 1970 to 2005. Data include lab number, region, analysis, organs, species, lake, form (whole fish, headon dressed, headless dressed), weight, and length and contaminant concentrations. Total mercury was the predominant contaminant measured. Results were expressed as ppm or ppb based on the parameter analyzed. Concentrations are expressed based on wet weight.