The Department of Fisheries and Oceans (DFO) holds discrete oceanographic, biological, and chemical data collected throughout the St. Lawrence Estuary, the Gulf of St. Lawrence, and the Saguenay Fjord, as well as data gathered outside of these zones during non-routine surveys (collected by the Quebec region). These data come from samples taken at different depths in the water column (surface, bottom, and intermediate depths), mainly during annual scientific missions such as:

- weekly monitoring at fixed stations (Rimouski, Shediac Valley)

- annual multispecies surveys (Northern and Southern Gulf)

- spring and fall missions of the Atlantic Zone Monitoring Program

This dataset presents the variables most frequently sampled for the period 1990 to two years prior to the present, namely, salinity, dissolved oxygen concentration, chlorophyll-a concentration, nutrient concentrations (nitrite, nitrate, silicate, phosphate), pH and alkalinity. These measurements are often accompanied by data from CTD profiles (Conductivity, Temperature, Depth/Pressure) and auxiliary sensors (fluorescence, turbidity, pH).

Annual synthesis of the chemical and biological oceanographic conditions of the study area have been published since 2011, and reports on zonal conditions of the four Atlantic regions of DFO are also available for certain years: https://www.dfo-mpo.gc.ca/science/data-donnees/azmp-pmza/index-eng.html

This record is updated annually as new data become available. To obtain access to earlier data, less frequently sampled variables, or specifications regarding laboratory analyses (analytical methods, preservation, and storage), please contact the data management team at: gddaiss-dmsaisb@dfo-mpo.gc.ca.

Notes: This publication contains data extracted from the national BioChem database (Biological and Chemical Marine Data: DFO.BioChemDatabase-BasededonneesBioChem.MPO@DFO-MPO.GC.CA ). When replicate samples were present, the values were averaged, and values were grouped by variable regardless of the analysis method, preservation method, or storage method.

The grouping of variables collected at the same station is based on spatial and temporal metadata: LATITUDE, LONGITUDE, DATE, and TIME.