Macroalgae and Benthic Macroinvertebrate Inventory Along Quebec Salinity Gradient

From September 26 to October 3, 2019, this inventory describes community structure across five small estuaries on Quebec's Upper North Shore. It uses a stratified random sampling design with 25 x 25 cm quadrats to measure species cover, biomass, and associated salinity levels. The data supports a doctoral study on benthic community responses to salinity changes in the St. Lawrence system.

Use Cases

• Analyze species biomass and percentage cover relationships across three hypoosmotic stress levels (low, medium, high) and a seawater control.
• Model community structure of macroalgae and benthic macroinvertebrates against measured salinity and substrate type variables.
• Study taxonomic diversity and species composition linked to specific quadrat eventID, date, and location information.

Strengths

• Data collection followed a structured protocol with quadrat sampling across five distinct estuaries and four defined salinity levels.
• Taxonomic identification was quality-controlled using a specific field guide and validated against the World Register of Marine Species (WoRMS).
• The dataset provides complementary files linked by eventID, including event information, salinity/substrate data, and detailed taxon occurrence with biomass.

Limitations

• The temporal coverage is limited to a single one-week period in late 2019, capturing a seasonal snapshot rather than long-term trends.
• Sampling was restricted to five specific estuaries selected for similar size, hard substrates, and accessibility, which may limit geographical generalizability.
• For some organisms like nudibranchs and barnacles, biomass was estimated from size rather than direct measurement, introducing potential estimation error.

Provenance

Source

Fisheries and Oceans Canada

Collection Method

Stratified random sampling using 25 x 25 cm quadrats. Percentage cover was estimated, organisms were weighed by species/size group, and salinity was measured with a portable refractometer and CTD probe.

Time Range

September 26 to October 3, 2019

Freshness

Data was collected in 2019; the record was last updated in March 2026.

Geography

Five small estuaries on the Upper North Shore of Quebec, Canada: Barthélemy Bay and the Colombier, Mistassini, Franquelin, and Saint-Nicolas rivers.