• Arctic SDI catalogue
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Demersal (groundfish) community diversity and biomass metrics in the Northern and Southern shelf bioregions

Description

Conservation of marine biodiversity requires understanding the joint influence of ongoing environmental change and fishing pressure. Addressing this challenge requires robust biodiversity monitoring and analyses that jointly account for potential drivers of change. Here, we ask how demersal fish biodiversity in Canadian Pacific waters has changed since 2003 and assess the degree to which these changes can be explained by environmental change and commercial fishing. Using a spatiotemporal multispecies model based on fisheries independent data, we find that species density (number of species per area) and community biomass have increased during this period. Environmental changes during this period were associated with temporal fluctuations in the biomass of species and the community as a whole. However, environmental changes were less associated with changes in species’ occurrence. Thus, the estimated increases in species density are not likely to be due to environmental change. Instead, our results are consistent with an ongoing recovery of the demersal fish community from a reduction in commercial fishing intensity from historical levels. These findings provide key insight into the drivers of biodiversity change that can inform ecosystem-based management.

The layers provided represent three community metrics: 1) species density (i.e., species richness), 2) Hill-Shannon diversity, and 3) community biomass. All layers are provided at a 3 km resolution across the study domain for the period of 2003 to 2019. For each metric, we provide layers for three summary statistics: 1) the mean value in each grid cell over the temporal range, 2) the probability that the grid cell is a hotspot for that metric, and 3) the temporal coefficient of variation (i.e., standard deviation/mean) across all years.

Methods:

The analysis that produced these layers is presented in Thompson et al. (2022). The analysis uses data from the Groundfish Synoptic Bottom Trawl Research surveys in Queen Charlotte Sound (QCS), Hecate Strait (HS), West Coast Vancouver Island (WCVI), and West Coast Haida Gwaii (WCHG) from 2003 to 2019. Cartilaginous and bony fish species caught in DFO groundfish surveys that were present in at least 15% of all trawls over the depth range in which they were caught were included. This depth range was defined as that which included 95% of all trawls in which that species was present. The final dataset used in our analysis consisted of 57 species (Table S1 in Thompson et al. 2022).

The spatiotemporal dynamics of the demersal fish community were modeled using the Hierarchical Modeling of Species Communities (HMSC) framework and package (Tikhonov et al. 2021) in R. This framework uses Bayesian inference to fit a multivariate hierarchical generalized mixed model. We modeled community dynamics using a hurdle model, which consists of two sub models: a presence-absence model and a biomass model that is conditional on presence. Our list of environmental covariates included bottom depth, bathymetric position index (BPI), mean summer tidal speed, substrate muddiness, substrate rockiness, whether the trawl was inside or outside of the ecosystem-based trawling footprint, and survey region (QCS & HS vs. WCVI & WCHG)), mean summer near-bottom temperature deviation, mean summer near-bottom dissolved oxygen deviation, mean summer cross-shore and along-shore current velocities near the seafloor, mean summer depth-integrated primary production, and local-scale commercial fishing effort.

Layers are provided for three community metrics. All metrics should be interpreted as the value that would be expected in the catch from an average tow in the Groundfish Synoptic Bottom Trawl Research Surveys taken in a given 3 km grid cell. Species density (sometimes called species richness) should be interpreted as the number of the 57 species that would be caught in a trawl. Hill-Shannon diversity is a measure of diversity that gives greater weight to communities where biomass is spread equally across species. Community biomass is the total biomass across all 57 species that would be expected to be caught per square km in an average tow.

Data Sources:

Research data was provided by Pacific Science's Groundfish Data Unit for research surveys from the GFBio database between 2003 and 2019 that occurred in four regions: Queen Charlotte Sound, Hecate Strait, West Coast Haida Gwaii, and West Coast Vancouver Island. Our analysis excludes species that are rarely caught in the research trawls and so our estimates would not include the occurrence or biomass of these rare species.

Commercial fishing data was accessed through a DFO R script detailed here: https://github.com/pbsassess/gfdata. Local scale commercial fishing effort was calculated from this data.

The substrate layers were obtained from a substrate model (Gregr et al. 2021).

The oceanographic layers (bottom temperature, dissolved oxygen, tidal and circulation speeds, primary production) were obtained from a hindcast simulation of the British Columbia continental margin (BCCM) model (Peña et al. 2019).

Uncertainties:

Species that are not well sampled by the trawl surveys may not be accurately estimated by our model. The model did not include spatiotemporal random effects, which likely underestimates spatiotemporal variability in the region. It is also important to underline covariate uncertainty and model uncertainty. The hotspot estimates provide one measure of model uncertainty/certainty.

Simple

Date ( RI_366 )
2022-10-28
Date ( RI_367 )
2023-02-27
Date ( RI_368 )
2023-05-09
Date ( RI_368 )
2024-11-12
RI_415
  Government of Canada; Fisheries and Oceans Canada; Pacific Science/Ecosystem Science Division/Marine Spatial Ecology & Analysis Section - Patrick Thompson ( Research Biologist )
Institute of Ocean Sciences 9860 West Saanich Road P.O. Box 6000 , Sidney , British Columbia , V8L 4B2 , Canada
604-999-3490
Status
completed; complété RI_593
Maintenance and update frequency
notPlanned; nonPlanifié RI_542
Keywords
  • species richness
  • community biomass
  • marine spatial planning
  • biodiversity change
  • environmental change
  • groundfish
  • ecosystem-based management
  • species distribution models
Government of Canada Core Subject Thesaurus Thésaurus des sujets de base du gouvernement du Canada ( RI_528 )
  • Fisheries
  • Marine biology
  • Fisheries resources
  • Ecosystems
  • Temperature
Classification
unclassified; nonClassifié RI_484
Use limitation
Open Government Licence - Canada (http://open.canada.ca/en/open-government-licence-canada)
Access constraints
license; licence RI_606
Use constraints
license; licence RI_606
Spatial representation type
grid; grille RI_636
Metadata language
eng; CAN
Character set
utf8; utf8 RI_458
Topic category
  • Biota
Begin date
2003
End date
2019
N
S
E
W
thumbnail


Reference system identifier
http://www.epsg-registry.org / EPSG:3005 /
Distribution format
  • TIFF ( unknown )

RI_412
  Government of Canada; Fisheries and Oceans Canada; Pacific Science/Ecosystem Science Division/Marine Spatial Ecology & Analysis Section - Patrick Thompson ( Research Biologist )
Institute of Ocean Sciences 9860 West Saanich Road P.O. Box 6000 , Sidney , British Columbia , V8L 4B2 , Canada
604-999-3490
OnLine resource
Demersal (groundfish) community diversity and biomass metrics in the Northern and Southern shelf bioregions - TIFF ( HTTPS )

Dataset;TIFF;eng

OnLine resource
Data Dictionary English ( HTTPS )

Supporting Document;CSV;eng

OnLine resource
References ( HTTPS )

Supporting Document;PDF;eng,fra

OnLine resource
Data Dictionary French ( HTTPS )

Supporting Document;CSV;fra

OnLine resource
Demersal (groundfish) community diversity and biomass metrics in the Northern and Southern shelf bioregions - GIS Hub metadata ( HTTPS )

Supporting Document;PDF;fra

OnLine resource
Demersal (groundfish) community diversity and biomass metrics in the Northern and Southern shelf bioregions - GIS Hub metadata ( HTTPS )

Supporting Document;PDF;eng

OnLine resource
Demersal (groundfish) community diversity and biomass metrics in the Northern and Southern shelf bioregions ( ESRI REST: Map Server )

Web Service;ESRI REST;eng

OnLine resource
Demersal (groundfish) community diversity and biomass metrics in the Northern and Southern shelf bioregions ( ESRI REST: Map Server )

Web Service;ESRI REST;fra

OnLine resource
Data Dictionary ( HTTPS )

Supporting Document;PDF;eng,fra

File identifier
3f4e85af-cc34-4aab-8e25-b956a792739f XML
Metadata language
eng; CAN
Character set
utf8; utf8 RI_458
Hierarchy level
dataset; jeuDonnées RI_622
Date stamp
2025-02-04T20:07:57.418Z
Metadata standard name
North American Profile of ISO 19115:2003 - Geographic information - Metadata
Metadata standard version
CAN/CGSB-171.100-2009
RI_415
  Government of Canada; Fisheries and Oceans Canada; Pacific Science/Ecosystem Science Division/Marine Spatial Ecology & Analysis Section - Emily Rubidge ( Research Scientist )
Institute of Ocean Sciences 9860 West Saanich Road P.O. Box 6000 , Sidney , British Columbia , V8L 4B2 , Canada
604-822-8419
 
 

Overviews

overview
Community Diversity

Spatial extent

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Keywords


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