Spatial distribution of the relative occurrence of Spotted Wolffish in the annual DFO groundfish research surveys conducted by the Québec (1978-2008) and Gulf (1971-2008) regions. Catch and effort data were aggregated by 100 km² cells. The probability of catching an Spotted Wolffish in a set and within a cell (relative occurrence) was calculated as the ratio of the number of sets in which a species was recorded and the total number of sets made. This method allows the mapping of catch and effort for numerous time series based on data from different programs in both the whole study area (research surveys and Sentinel Fisheries using bottom trawls and a random stratified design) or in specific areas within the Gulf. Source: Dutil, J.-D., S. Proulx, S. Hurtubise, and J. Gauthier 2011. Recent findings on the life history and catches of wolffish (Anarhichas sp.) in research surveys and in the Sentinel Fisheries and Observer Program for the Estuary and Gulf of St-Lawrence. DFO Can. Sci. Advis. Sec. Res. Doc. 2010/126: x + 71 pages. Associated publication: Dutil, J.-D., Proulx, S., Chouinard, P.-M., and Borcard, D. 2011. A hierarchical classification of the seabed based on physiographic and oceanographic features in the St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci. 2916: vii + 72 pages. http:/ / www.dfo-mpo.gc.ca/ Library/ 342703.pdf.

Spatial distribution of the Winter Skate relative occurrence based on the annual Department of Fisheries and Oceans (DFO) groundfish research surveys realised between 2004 and 2010. The probability of catching a Winter Skate in a set and within a cell (relative occurrence) was calculated as the ratio of the number of sets in which a species was recorded and the total number of sets made. Catch and set data were aggregated using a grid made up of 100 km² cells. They are derived from processed data used for the production of: Chouinard, P-M., J-D. Dutil, S. Proulx, D. Borcard and J. Crocker. 2014. A spatial approach to matching marine fish diversity and abundance with habitat features. Hydrobiologia. Volume 734, Issue 1: 39-55. Associated publication: Dutil, J.-D., Proulx, S., Chouinard, P.-M., and Borcard, D. 2011. A hierarchical classification of the seabed based on physiographic and oceanographic features in the St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci. 2916: vii + 72 pages. Purpose Since 1990, the Department of Fisheries and Oceans has been conducting an annual multidisciplinary survey in the Estuary and northern Gulf of St. Lawrence using a standardized protocol. In the southern Gulf of St. Lawrence, these bottom trawl surveys has been carrying out each September since 1971. These missions are an important source of information about the status of the marine ressources. The objectives of the surveys are multiple: to estimate the abundance and biomass of groundfish and invertebrates, to identify the spatial distribution and biological characteristics of these species, to monitor the biodiversity of the Estuary and Gulf and finally, to describe the environmental conditions observed in the area at the moment of the sampling. The southern Gulf surveys are realized using the following standardized protocol: Hurlbut,T. and D.Clay (eds) 1990. Protocols for Research Vessel Cruises within the Gulf Region (Demersal Fish) (1970-1987). Can. MS Rep. Fish. Aquat. Sci. No. 2082: 143p. The sampling protocols used for the Estuary and northern Gulf surveys are described in details in the following publications: Bourdages, H., Archambault, D., Bernier, B., Fréchet, A., Gauthier, J., Grégoire, F., Lambert, J., et Savard, L. 2010. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d’août 2009 dans le nord du golfe du Saint-Laurent. Rapp. stat. can. sci. halieut. aquat. 1226 : xii+ 72 p. Bourdages, H., Archambault, D., Morin, B., Fréchet, A., Savard, L., Grégoire, F., et Bérubé, M. 2003. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d’août 2003 dans le nord du golfe du Saint-Laurent. Secr. can. consult. sci. du MPO. Doc. rech. 2003/078. vi + 68 p. Annual reports are available at the Canadian Science Advisory Secretariat (CSAS), (http://www.dfo-mpo.gc.ca/csas-sccs/index-eng.htm).

Spatial distribution of lumpfish catch rates (number per tow) during the August DFO research survey conducted annually since 1990, to assess the state of groundfish and shrimp stocks in the northern Gulf of St. Lawrence. The area sampled by a tow is the product of the distance trawled (fishing time multiplied by vessel speed) and the wing spread (13.41 m for the Alfred Needler and 16.94 m for the Teleost). Given that this area may vary among tows, the sampling unit is standardized and defined as being a station sampled by a tow over a distance of 0.75 nautical miles (1,389 m) with a horizontal wing spread of 16.94 m. Catch variables were calculated based on the standard area, 0.02353 km². After each tow, the catch was sorted by taxa, and the number of individuals and total biomass of these taxa were noted. For taxa identified to the species level, individual biometric parameters (e.g., length, weight) and biological parameters (e.g., sex, maturity of gonads) were recorded based on a subsample. Full methods are described in Bourdages et al. (2010). Note that the increase in catch rate for the 2005-2009 period coincides with a change in gear for this survey. Bourdages, H., and Ouellet, J.-F. 2011. Geographic distribution and abundance indices of marine fish in the northern Gulf of St. Lawrence (1990–2009). Can. Tech. Rep. Fish. Aquat. Sci. 2963: vi + 171 p. Source: Gauthier, J., Grégoire, F., and Nozères, C. 2017. Assessment of Lumpfish (Cyclopterus lumpus) in the Gulf of St. Lawrence (3Pn, 4RS) in 2015. DFO Can. Sci. Advis. Sec. Res. Doc. 2017/051. v + 47 p. Purpose The multidisciplinary survey of groundfish and shrimp in the northern Gulf of St. Lawrence has been conducted every August by Fisheries and Oceans Canada for more than two decades. Initially, its objective was to determine the abundance and geographic distribution of commercially important taxa. However, for couple of years, the objective was expanded to include all taxa caught with the shift toward the ecosystem approach.

Spatial distribution of the relative occurrence of northern wolffish in the annual DFO groundfish research surveys conducted by the Québec (1978-2008) and Gulf (1971-2008) regions. Catch and effort data were aggregated by 100 km² cells. The probability of catching an northern wolffish in a set and within a cell (relative occurrence) was calculated as the ratio of the number of sets in which a species was recorded and the total number of sets made. This method allows the mapping of catch and effort for numerous time series based on data from different programs in both the whole study area (research surveys and Sentinel Fisheries using bottom trawls and a random stratified design) or in specific areas within the Gulf. Source: Dutil, J.-D., S. Proulx, S. Hurtubise, and J. Gauthier 2011. Recent findings on the life history and catches of wolffish (Anarhichas sp.) in research surveys and in the Sentinel Fisheries and Observer Program for the Estuary and Gulf of St-Lawrence. DFO Can. Sci. Advis. Sec. Res. Doc. 2010/126: x + 71 pages. Associated publication: Dutil, J.-D., Proulx, S., Chouinard, P.-M., and Borcard, D. 2011. A hierarchical classification of the seabed based on physiographic and oceanographic features in the St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci. 2916: vii + 72 pages. http:/ / www.dfo-mpo.gc.ca/ Library/ 342703.pdf.

Spatial distribution of the relative occurrence of Atlantic Wolffish in the annual DFO groundfish research surveys conducted by the Québec (1978-2008) and Gulf (1971-2008) regions. Catch and effort data were aggregated by 100 km² cells. The probability of catching an Atlantic Wolffish in a set and within a cell (relative occurrence) was calculated as the ratio of the number of sets in which a species was recorded and the total number of sets made. This method allows the mapping of catch and effort for numerous time series based on data from different programs in both the whole study area (research surveys and Sentinel Fisheries using bottom trawls and a random stratified design) or in specific areas within the Gulf. Source: Dutil, J.-D., S. Proulx, S. Hurtubise, and J. Gauthier 2011. Recent findings on the life history and catches of wolffish (Anarhichas sp.) in research surveys and in the Sentinel Fisheries and Observer Program for the Estuary and Gulf of St-Lawrence. DFO Can. Sci. Advis. Sec. Res. Doc. 2010/126: x + 71 pages. Associated publication: Dutil, J.-D., Proulx, S., Chouinard, P.-M., and Borcard, D. 2011. A hierarchical classification of the seabed based on physiographic and oceanographic features in the St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci. 2916: vii + 72 pages. http:/ / www.dfo-mpo.gc.ca/ Library/ 342703.pdf.

Spatial distribution of the Thorny Skate presence expressed by catch weight based on the annual Department of Fisheries and Oceans (DFO) groundfish research surveys realised between 2004 and 2010. Catch data (kg/nautical mile) were aggregated by 100 km² cells. They are derived from processed data used for the production of: Chouinard, P-M., J-D. Dutil, S. Proulx, D. Borcard and J. Crocker. 2014. A spatial approach to matching marine fish diversity and abundance with habitat features. Hydrobiologia. Volume 734, Issue 1: 39-55. Associated publication: Dutil, J.-D., Proulx, S., Chouinard, P.-M., and Borcard, D. 2011. A hierarchical classification of the seabed based on physiographic and oceanographic features in the St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci. 2916: vii + 72 pages. Purpose Since 1990, the Department of Fisheries and Oceans has been conducting an annual multidisciplinary survey in the Estuary and northern Gulf of St. Lawrence using a standardized protocol. In the southern Gulf of St. Lawrence, these bottom trawl surveys has been carrying out each September since 1971. These missions are an important source of information about the status of the marine ressources. The objectives of the surveys are multiple: to estimate the abundance and biomass of groundfish and invertebrates, to identify the spatial distribution and biological characteristics of these species, to monitor the biodiversity of the Estuary and Gulf and finally, to describe the environmental conditions observed in the area at the moment of the sampling. The southern Gulf surveys are realized using the following standardized protocol: Hurlbut,T. and D.Clay (eds) 1990. Protocols for Research Vessel Cruises within the Gulf Region (Demersal Fish) (1970-1987). Can. MS Rep. Fish. Aquat. Sci. No. 2082: 143p. The sampling protocols used for the Estuary and northern Gulf surveys are described in details in the following publications: Bourdages, H., Archambault, D., Bernier, B., Fréchet, A., Gauthier, J., Grégoire, F., Lambert, J., et Savard, L. 2010. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d’août 2009 dans le nord du golfe du Saint-Laurent. Rapp. stat. can. sci. halieut. aquat. 1226 : xii+ 72 p. Bourdages, H., Archambault, D., Morin, B., Fréchet, A., Savard, L., Grégoire, F., et Bérubé, M. 2003. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d’août 2003 dans le nord du golfe du Saint-Laurent. Secr. can. consult. sci. du MPO. Doc. rech. 2003/078. vi + 68 p. Annual reports are available at the Canadian Science Advisory Secretariat (CSAS), (http://www.dfo-mpo.gc.ca/csas-sccs/index-eng.htm).

Spatial distribution of the Smooth Skate presence expressed by catch weight based on the annual Department of Fisheries and Oceans (DFO) groundfish research surveys realised between 2004 and 2010. Catch data (kg/nautical mile) were aggregated by 100 km² cells. They are derived from processed data used for the production of: Chouinard, P-M., J-D. Dutil, S. Proulx, D. Borcard and J. Crocker. 2014. A spatial approach to matching marine fish diversity and abundance with habitat features. Hydrobiologia. Volume 734, Issue 1: 39-55. Associated publication: Dutil, J.-D., Proulx, S., Chouinard, P.-M., and Borcard, D. 2011. A hierarchical classification of the seabed based on physiographic and oceanographic features in the St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci. 2916: vii + 72 pages. Purpose Since 1990, the Department of Fisheries and Oceans has been conducting an annual multidisciplinary survey in the Estuary and northern Gulf of St. Lawrence using a standardized protocol. In the southern Gulf of St. Lawrence, these bottom trawl surveys has been carrying out each September since 1971. These missions are an important source of information about the status of the marine ressources. The objectives of the surveys are multiple: to estimate the abundance and biomass of groundfish and invertebrates, to identify the spatial distribution and biological characteristics of these species, to monitor the biodiversity of the Estuary and Gulf and finally, to describe the environmental conditions observed in the area at the moment of the sampling. The southern Gulf surveys are realized using the following standardized protocol: Hurlbut,T. and D.Clay (eds) 1990. Protocols for Research Vessel Cruises within the Gulf Region (Demersal Fish) (1970-1987). Can. MS Rep. Fish. Aquat. Sci. No. 2082: 143p. The sampling protocols used for the Estuary and northern Gulf surveys are described in details in the following publications: Bourdages, H., Archambault, D., Bernier, B., Fréchet, A., Gauthier, J., Grégoire, F., Lambert, J., et Savard, L. 2010. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d’août 2009 dans le nord du golfe du Saint-Laurent. Rapp. stat. can. sci. halieut. aquat. 1226 : xii+ 72 p. Bourdages, H., Archambault, D., Morin, B., Fréchet, A., Savard, L., Grégoire, F., et Bérubé, M. 2003. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d’août 2003 dans le nord du golfe du Saint-Laurent. Secr. can. consult. sci. du MPO. Doc. rech. 2003/078. vi + 68 p. Annual reports are available at the Canadian Science Advisory Secretariat (CSAS), (http://www.dfo-mpo.gc.ca/csas-sccs/index-eng.htm).

1999 to 2023 surface temperature and salinity measured along the track of commercial ships, mostly between Montreal (Quebec) and St. John's (Newfoundland). Monitoring of surface water conditions in the Estuary and Gulf of St. Lawrence is carried out with different complementary methods such as thermosalinographs (TSG) installed on commercial ships. These ships are sailing all year long from Montreal to St. John’s, one round trip per week, and are sampling water near the surface (3 to 8 meters deep) to determine the temperature and salinity all along the route. Purpose The recorded data are used as input to numerical forecasting models for sea ice conditions and as a monitoring tool for the Gulf of St. Lawrence. Annual reports are available at the Canadian Science Advisory Secretariat (CSAS), (http://www.dfo-mpo.gc.ca/csas-sccs/index-eng.htm). Galbraith, P.S., Chassé, J., Caverhill, C., Nicot, P., Gilbert, D., Lefaivre, D. and Lafleur, C. 2018. Physical Oceanographic Conditions in the Gulf of St. Lawrence during 2017. DFO Can. Sci. Advis. Sec. Res. Doc. 2018/050. v + 79 p.

A geospatial database involving 130 descriptors was created describing the pelagic and benthic habitats of the 0–30 m surface layer in the estuary and Gulf of St. Lawrence. A grid made of 6.25 km² cells (2.5 x 2.5 km) was used to aggregate the data. Each of the 39,337 cells overlapping the marine environment was characterized using landscape, hydrographic, and oceanographic parameters determined from observations (including satellite imagery), a 3D circulation model, and published and unpublished material available at local and regional scales. Purpose The dataset provides useful information on the spatial extent of major coastal epipelagic habitats in the study area and can be used for mapping purposes and for analyses of species-habitat relationships. Additional Information The low tide limit was taken as the upper (0 m) boundary, but neighbouring landscape features, such as the proximity to freshwater inflows, surface area of the tidal zone, and characteristics of the shoreline, were also taken into consideration. Also, each cell was classified as being marine, intertidal, or terrestrial using the high and low tide marks. Those marks were determined using NRCan CANVEC topographic map products (1:50,000). The high tide mark was determined as the limit between the land and water layers. The low tide mark (0 m depth) was determined as the lower limit of the tidal zone in areas with a tidal zone, and as the limit between the land and water layers elsewhere. See the report mentioned below for a more detailed description of the treatments for each variable: Dutil, J.-D., S. Proulx, P. Galbraith, J. Chassé and N. Lambert 2012. Coastal and epipelagic habitats of the St. Lawrence estuary and Gulf. Can. Tech. Rep. Fish. Aquat. Sci. 3009 : ix +87 pp.

Available information for the Estuary and Gulf of St. Lawrence on salinity, temperature, dissolved oxygen, depth, slope, and variability in landscape and sediments, were aggregated using a grid made up of 100 km2 cells as a basis for mapping and describing marine habitats for conservation and integrated management purposes. For example, 26 variables were selected to describe depth, slope, salinity and temperature. Based on that information, cluster analyses were conducted grouping cells into 13 different megahabitats. Four megahabitats described the deep waters, and areas outside channels formed 9 megahabitats: four in the southern Gulf and five in the northern Gulf. Purpose The tool proposes a novel way of making validated and integrated data available to end users. Potential applications include the screening of areas considered for inclusion in a network of protected areas and a quantitative assessment of surface areas for each class of habitat. The method can also be applied to describe the habitats of species at risk. Additional Information See the report mentioned below for a more detailed description of the treatments for each variable: Dutil, J.-D., Proulx, S., Chouinard, P.-M., and Borcard. D. 2011. A hierarchical classification of the seabed based on physiographic and oceanographic features in the St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci. 2916: vii + 72 p.