Description

Casault, B., Johnson, C.L., Devred, E., Clay, S., and Beazley, L. 2025. Chemical and Biological Oceanographic Conditions on the Scotian Shelf and in the Eastern Gulf of Maine during 2024. Can. Tech. Rep. Fish. Aquat. Sci. 3744: vi + 58 p. https://doi.org/10.60825/p6ad-1k52 Nutrient and plankton conditions were assessed in the context of physical conditions observed in the Maritimes Region in 2024. Nutrient depletion was widespread across the region, with Prince 5 (P5) station recording its tenth consecutive year of below-normal surface and subsurface nitrate inventories, while Cabot Strait section recorded record-low inventories for surface nitrate, silicate, and phosphate. Lower nutrient conditions likely influenced phytoplankton productivity, as chlorophyll-a measured in situ or derived from satellite remote sensing was mainly near or below normal across the region. The spring phytoplankton bloom was earlier than normal in the eastern area, near normal in the central area, and later than normal in the western area of the region. The intensity of the spring bloom was mainly normal to slightly below normal regionwide (except for Lurcher Shoal). The onset of the fall phytoplankton bloom was delayed across most areas, with the Eastern Scotian Shelf indicating a record-late onset. The intensity of the fall bloom was variable but mainly within near-normal ranges. Calanus finmarchicus abundance was near normal for the core sections, but negative and positive anomalies were recorded at the Halifax-2 (HL2) and P5 stations, respectively. Pseudocalanus spp. abundance reached record-high levels for the Halifax section, but was otherwise near normal. Mesozooplankton biomass was above normal at P5 but mainly below normal elsewhere, with record-low biomass observed at HL2. Arctic Calanus species and warm-water offshore copepods mainly remained at or below normal abundances, while warm-water shelf copepods showed near-normal abundances except for negative anomalies observed for the Halifax section and at P5.

Resources

Name	Format	Description	Link
Figure 11 : Chlorophyll a inventory at the Maritimes high-frequency sampling stations	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_11.zip
Figure 17 : Zooplankton (> 200 µm) abundance and community composition at the Maritimes high-frequency sampling stations	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_17.zip
Figure 18 : Annual anomaly scorecards for zooplankton abundance and biomass	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_18.zip
Figure 19 : Copepod abundance and composition at the Maritimes high-frequency sampling stations	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_19.zip
Figure 21 : Calanus finmarchicus abundance and developmental stage distribution at the Maritimes high-frequency sampling stations	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_21.zip
Figure 22 : Zooplankton biomass at the Maritimes high-frequency sampling stations	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_22.zip
Figure 23 : Calanus finmarchicus abundance during the ecosystem trawl surveys	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_23.zip
Figure 24 : Mesozooplankton dry biomass during the ecosystem trawl surveys	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_24.zip
Figure 25 : Calanus finmarchicus abundance during the seasonal surveys on the core sections	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_25.zip
Figure 26 : Mesozooplankton dry biomass during the seasonal surveys on the core sections	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_26.zip
Figure 27 : Annual anomaly scorecard for non-copepod groups abundance on the Scotian Shelf sections	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_27.zip
Figure 28 : Annual anomaly scorecards for copepod indicator species grouped abundance	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_28.zip
Figure 06 : Nitrate inventories at the Maritimes high-frequency sampling stations	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_6.zip
Figure 07 : Annual anomaly scorecards for surface (0–50 m) and deep (50–150 m) nitrate, silicate, and phosphate inventories	CSV		https://api-proxy.edh-cde.dfo-mpo.gc.ca/catalogue/records/2a309246-c18c-43fb-a8e5-d81768363441/attachments/Figure_7.zip
Canadian Technical Report of Fisheries and Aquatic Sciences 3744	PDF		https://science-catalogue.canada.ca/record=4131025~S6

Tags

Topics

Categories