Demersal Fish Community Metrics for Canadian Pacific Waters 2003-2019

Fisheries and Oceans Canada provides three community metrics—species density, Hill-Shannon diversity, and community biomass—for 57 demersal fish species. The data consists of raster layers at a 3 km resolution across four survey regions from 2003 to 2019, with each metric summarized as a mean value, hotspot probability, and temporal coefficient of variation. This analysis uses a spatiotemporal multispecies model based on fisheries-independent trawl survey data to assess drivers of biodiversity change.

Use Cases

• Model spatiotemporal trends in community biomass using the provided mean and coefficient of variation layers for the 2003-2019 period.
• Identify biodiversity hotspots by analyzing the probability layers for species density and Hill-Shannon diversity across the 3 km grid.
• Assess the relationship between environmental change and species occurrence using the hurdle model framework applied to 57 fish species.
• Map the mean species density (species richness) per grid cell to visualize spatial patterns in the Northern and Southern shelf bioregions.

Strengths

• Covers 57 demersal fish species, providing a detailed community-level analysis.
• Offers 17 years of temporal coverage (2003-2019) for tracking long-term trends.
• Provides data at a fine 3 km spatial resolution across four distinct survey regions in Canadian Pacific waters.
• Each of the three core metrics (species density, Hill-Shannon diversity, biomass) is accompanied by three derived statistical layers (mean, hotspot probability, coefficient of variation).

Limitations

• The analysis is limited to species present in at least 15% of trawls within their specific depth range, potentially excluding rare species.
• Spatial coverage is restricted to four specific survey regions (e.g., Queen Charlotte Sound, Hecate Strait), not the entire Canadian Pacific.
• The underlying model is a complex Bayesian hierarchical framework (HMSC), which may require specialized statistical knowledge to interpret or extend.

Provenance

Source

Fisheries and Oceans Canada

Collection Method

Data derived from Groundfish Synoptic Bottom Trawl Research surveys, analyzed using the Hierarchical Modeling of Species Communities (HMSC) framework in R.

Time Range

2003 to 2019

Freshness

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Geography

Queen Charlotte Sound, Hecate Strait, West Coast Vancouver Island, and West Coast Haida Gwaii in Canadian Pacific waters.