Time series of dissolved inorganic nutrients (nitrate, silicate, phosphate) (mmol/m2) 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 integrated nutrient data of 2 strata (0-50 m) et (50-150 m) from the last ten years are displayed as 12 layers, 6 for the June survey (2013-2022, 2020 not sampled) and 6 for the autumn survey (2013-2022). Finally, 2 other layers 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 time series of nutrients and with a .csv file containing all the integrated nutrient data acquired at those stations since the beginning of the program sampling (columns : Station, Latitude, Longitude, Date(UTC), Sounding(m), Depth_min/Profondeur_min(m), Depth_max/Profondeur_max(m), Integrated_Nitrate/Nitrate_intégré(mmol/m²), Integrated_Phosphate/Phosphate_intégré(mmol/m²), Integrated_Silicate/Silice_intégrée(mmol/m²)). 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 Water sampling for nutrients analysis is done from Niskin bottles 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.

Mean 2013 to 2022 summer surface conditions in the Estuary and Gulf of St. Lawrence. Data come from the August and the September multidisciplinary surveys. Surface conditions are described by temperature, salinity and nutrient concentration (mmol/m³) interpolated on a 10 km x 10 km grid. 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). 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.

Mean 2014 to 2023 winter surface conditions in the Estuary and Gulf of St. Lawrence. The survey has been taking place every year in March. Surface conditions are described by temperature, salinity and nutrient concentration (mmol/m3) interpolated on a 10km x 10km grid. Purpose Since many years, the Department of Fisheries and Oceans Canada (DFO) has been conducting annual surveys, at different periods of the year, in the Estuary and Gulf of St. Lawrence, each having many objectives including assessment of environmental conditions. However, these surveys, carried out on vessels, did not cover the winter period. Since 1996, a regional monitoring program, conducted by Maurice-Lamontagne Institute scientists, is taking place in order to fill this gap. The annual helicopter survey is undertaken in the beginning of March to evaluate physical oceanographic conditions of waters up to 200 m and surface water nutrient contains. These surveys are usually sampled from a Canadian Coast Guard helicopter but from an icebreaker in 2016 and 2017. Data from regional monitoring programs are combined with the ones from the Atlantic Zone Monitoring Program (AZMP) to produce annual reports (physical, biological and a Zonal Scientific Advice) which 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., Pettigrew, B., Lefaivre, D., Brickman, D., Devine, L., and Lafleur, C. 2017. Physical Oceanographic Conditions in the Gulf of St. Lawrence in 2016. DFO Can. Sci. Advis. Sec. Res. Doc. 2017/044. v + 91 p. 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. Additional Information Water sampling for nutrient analysis is done from Niskin bottles 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. Nitrate titration is carried out according to the following method ((nitrite + nitrate) – nitrite): Nitrite + nitrate: Armstrong, FAJ, CR Stearns, JDH Strickland (1967) The measurement of upwelling and subsequent biological processes by means of the Technicon Autoanalyzer and associated equipment. Deep-Sea Res 14(3) 381-389. Nitrite: American Public Health Assoc. (1971) Standard Methods for the examination of water and wastewater. 13th edition, pp. 240-243, Washington D.C. Phosphate: Murphy, J, JP Riley (1962) A modified single solution method for the determination of phosphate in natural waters. Anal Chim. Acta 27 : 30. Silicate: Strickland, JDH, TR Parsons (1972) A Practical Handbook of Seawater Analysis, second edition. Fish Res Board Can, Bulletin 167, 310 pp. The surface water temperature and salinity are determined from CTD profiles.

Phytoplankton species abundance (cell/L) and oceanographic conditions (temperature, salinity, chlorophylle-a (mg/m³) for some years and nutrient content (mmol/m³)) at stations of the Harmful Algae Monitoring Programme (HAMP) from1994 to 2016. The layer presents the station positions of the HAMP. Two files are attached to each station: one containing the cell counts and the second the oceanographic conditions. Purpose The summer growth of many toxic and harmful microalgae species poses a serious threat for the public health and commercial or recreational exploitation of some marine species. The Department of Fisheries and Oceans (DFO) initiated the Harmful Algae Monitoring Programme (HAMP) in 1989 in order to complete the monitoring program for paralytic shellfish poisoning (PSP). Under the responsibility of Maurice-Lamontagne Institute scientists, the HAMP is to monitor, by means of a coastal station network, the natural occurrence of toxic and harmful algae in the St. Lawrence in order to determine their spatio-temporal distribution and the environmental conditions leading to their bloom. The network is made up of 11 coastal stations which are sampled every week from April to November and which are established along Quebec eastern shores. It extends from Tadoussac to Tête-à-la-Baleine on the St. Lawrence north shore and from Sainte-Flavie to Carleton on the south shore along the Gaspé peninsula. Another station is located in Havre-Aux-Maisons, Magdalen Islands. The HAMP was discontinued in 2010 but opportunistic samplings are still done at some stations. Additional information The sampling and analysis protocol is described in details in the following publication apart from the fact that the number of identified and counted species significantly has been increasing with time. Phytoplankton samples are preserved in a lugol solution. Blasco D., M. Levasseur, R. Gélinas, R. Larocque, A.D. Cembella, B. Huppertz et E. Bonneau.1998. Monitorage du phytoplancton toxique et des toxines de type IPM dans les mollusques du Saint-Laurent: 1989 à 1994. Rapp. stat. can. hydrogr. sci. océan. 15 1 : x i-117 p.