Phytoplankton, Toxic Algae and Zooplankton in the Estuary and Gulf of St. Lawrence 2025
Highlights
Phytoplankton, toxic algae and zooplankton communities in the Estuary and Gulf of St. Lawrence remained stable or declined during the 2020–2024 period. Phytoplankton biomass increased, with spring blooms occurring earlier compared with the reference period. Although the toxic algae indicator was rated Moderate–Good for 2020–2024, a record bloom of Pseudo-nitzschia was recorded in 2021. Zooplankton biomass decreased, and the development of Calanus finmarchicus, a key species in the marine food web, occurred significantly early.