Spotted Wolffish Relative Occurrence in St. Lawrence Estuary and Gulf

Fisheries and Oceans Canada provides spatial distribution data on Spotted Wolffish relative occurrence from annual groundfish research surveys. The dataset aggregates catch and effort data into 100 km² cells for the Québec (1978-2008) and Gulf (1971-2008) regions. It maps the probability of catching a Spotted Wolffish per set within each cell.

Use Cases

• Analyze spatial distribution trends of Spotted Wolffish relative occurrence across 100 km² cells over the 1971-2008 time series.
• Model habitat suitability by correlating relative occurrence values with seabed physiographic and oceanographic features from the associated publication.
• Compare catch probability metrics between the Québec and Gulf survey regions to assess regional population differences.
• Integrate the relative occurrence data with other survey data using the 100 km² cell grid as a spatial join key for broader ecosystem analysis.

Strengths

• Data spans a long-term time series from 1971 to 2008, providing over three decades of ecological observation.
• Spatial aggregation into standardized 100 km² cells enables consistent mapping and analysis across the study area.
• Methodology is documented in a peer-reviewed Department of Fisheries and Oceans scientific advisory document.

Limitations

• The underlying raw catch and effort data or row counts are not provided, limiting reproducibility of the calculated relative occurrence.
• Data is temporally stale, with the latest survey year being 2008, and may not reflect current population status.
• The dataset's spatial resolution is limited to 100 km² cells, which may obscure finer-scale habitat preferences.

Provenance

Source

Fisheries and Oceans Canada, based on research by Dutil, J.-D., et al.

Collection Method

Calculated from annual DFO groundfish research surveys using bottom trawls and a random stratified design. Relative occurrence is the ratio of sets with a species to total sets per 100 km² cell.

Time Range

1971 to 2008 (Gulf region: 1971-2008; Québec region: 1978-2008).

Freshness

Data covers up to 2008; the platform record was last updated in 2026, but the underlying data is not recent.

Geography

Estuary and Gulf of St. Lawrence, Canada.