Deep water (> 200 m) dissolved oxygen interpolated on a grid cell of 10 km x10 km in the Estuary and Gulf of St. Lawrence. Input data are from the annual August multidisciplinary survey hold in 2014 to 2023. 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. These surveys are an important source of information about the status of the marine ressources. The objectives of the survey 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 the northern Gulf and finally, to describe the environmental conditions observed in August in the sampling area. Annual reports are available at the Canadian Science Advisory Secretariat (CSAS), (http://www.dfo-mpo.gc.ca/csas-sccs/index-eng.htm). Bourdages, H., Brassard, C., Desgagnés, M., Galbraith, P., Gauthier, J., Légaré, B., Nozères, C. and Parent, E. 2017. Preliminary results from the groundfish and shrimp multidisciplinary survey in August 2016 in the Estuary and northern Gulf of St. Lawrence. DFO Can. Sci. Advis. Sec. Res. Doc. 2017/002. v + 87 p. Supplemental Information The bottom dissolved oxygen is determined from a CTD profile in the water column according to AZMP sampling protocol: Mitchell, M. R., Harrison, G., Pauley, K., Gagné, A., Maillet, G., and Strain, P. 2002. Atlantic Zonal Monitoring Program sampling protocol. Can. Tech. Rep. Hydrogr. Ocean Sci. 223: iv + 23 pp.

Bottom dissolved oxygen time series at the 3 fixed stations and 46 stations, grouped into transects, of the Atlantic Zonal Monitoring Program (AZMP) under the Quebec region responsibility. The mean bottom dissolved oxygen of the last ten years are displayed as 2 layers, one for the June survey (2014-2023, 2020 not sampled), another for the autumn survey (2014-2023). A third layer shows the positions of the fixed stations of the program (Anticosti Gyre, Gaspé Current and Rimouski). Each station is linked with a .png file showing the bottom dissolved oxygen time series and with a .csv file containing all the bottom dissolved oxygen data acquired at those stations since the beginning of the program sampling (columns : Station, Latitude, Longitude, Date(UTC), Sounding(m), Depth/Profondeur(m), Dissolved_Oxygen/Oxygène_Dissous(%sat)). Purpose The Atlantic Zone Monitoring Program (AZMP) was implemented in 1998 with the aim of increasing the Department of Fisheries and Oceans Canada’s (DFO) capacity to detect, track and predict changes in the state and productivity of the marine environment. The AZMP collects data from a network of stations composed of high-frequency monitoring sites and cross-shelf sections in each following DFO region: Québec, Gulf, Maritimes and Newfoundland. The sampling design provides basic information on the natural variability in physical, chemical, and biological properties of the Northwest Atlantic continental shelf. Cross-shelf sections sampling provides detailed geographic information but is limited in a seasonal coverage while critically placed high-frequency monitoring sites complement the geography-based sampling by providing more detailed information on temporal changes in ecosystem properties. In Quebec region, two surveys (46 stations grouped into transects) are conducted every year, one in June and the other in autumn in the Estuary and Gulf of St. Lawrence. Historically, 3 fixed stations were sampled more frequently. One of these is the Rimouski station that still takes part of the program and is sampled about weekly throughout the summer and occasionally in the winter period. Annual reports (physical, biological and a Zonal Scientific Advice) are available from the Canadian Science Advisory Secretariat (CSAS), (http://www.dfo-mpo.gc.ca/csas-sccs/index-eng.htm). Devine, L., Scarratt, M., Plourde, S., Galbraith, P.S., Michaud, S., and Lehoux, C. 2017. Chemical and Biological Oceanographic Conditions in the Estuary and Gulf of St. Lawrence during 2015. DFO Can. Sci. Advis. Sec. Res. Doc. 2017/034. v + 48 pp. Supplemental Information Bottom dissolved oxygen is determined from CTD profile in the water column according to AZMP sampling protocol: Mitchell, M. R., Harrison, G., Pauley, K., Gagné, A., Maillet, G., and Strain, P. 2002. Atlantic Zonal Monitoring Program sampling protocol. Can. Tech. Rep. Hydrogr. Ocean Sci. 223: iv + 23 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.