Assessing indirect biodiversity conservation benefits of fisheries closures in the Gulf of St. Lawrence, Canada

increase in bottom temperature, decrease in bottom oxygen concentration, decrease in bottom pH [44]. Data analyses Spatio-temporal changes in the bottom environment. We extracted spatially resolved (0.05˚ x 0.05˚ grid cell resolution) ensemble mean projections for bottom temperature, oxygen Table 2. Data sets, data types, methods and variables combined to analyze indirect current and future biodiversity conservation benefits of Other Effective Conser- vation Measures (OECMs) in the Gulf of St. Lawrence. SSP = Shared Socioeconomic Pathways; CMIP6: Couple Inter-model Intercomparison Project 6. Data set Data types, methods and variables Source OECMs Shapefiles of OECM boundaries with the following attributes: Name of area, area size (km2), primary biodiversity conservation objective, prohibitions within area, location, and weblink to each area profile. From these weblinks, we derived information on the indirect biodiversity conservation objectives. [45] Significant benthic habitats Shapefiles of significant benthic habitats for cold-water sponges and sea pens, with information of location and size of habitat (km2). These habitats were identified using Kernel density estimation and species distribution modeling. This method creates a modelled biomass surface for each taxon and an aerial expansion method permitted to identify significant concentrations of sponges and sea pens. The borders of the areas were refined using knowledge of null catches and species distribution models. Predictive models were produced using a random forest machine- learning technique. [46–48]

Potential Atlantic halibut spawning habitat Likelihood (probability from 0–1) of Atlantic halibut spawning habitat in the Gulf of St. Lawrence, based on reconstructed movement tracks, derived from pop-up satellite archival tags, using a statistical geolocation Hidden Markov model. Likelihood is represented as the number of individual spawning events per grid cell (defined as location of tagged individual) during 2014– 2016 and 2018 (winters). [49] Potential Greenland halibut spawning habitat Potential spawning area for Greenland halibut in the Gulf of St. Lawrence, based information from ichthyoplankton and bottom trawl surveys during 2005–2009. [50, 51] Potential redfish spawning habitat Density and distribution of redfish larva in the Gulf of St. Lawrence based on plankton sampling between 22 June and 4 July 1991 and at 74 stations, and between 10 June and 20 June 1992. [52] Preferred temperature ranges for non-spawning and spawning adults Redfish Non-spawning: 3–8 ˚C [53, 54] Spawning: 3.7–6.2 ˚C Greenland halibut Non-spawning: -1.9–9 ˚C [55, 56] Spawning: 2.8–4.1 ˚C Atlantic halibut Non-spawning: -1.5–15 ˚C [15, 57] Spawning: 5–7 ˚C Climate change projections Decadal, present day (2010–2020) and future projections of (2050– 2060; 2090–2100) mean conditions along the sea bottom for temperature (˚C), oxygen concentration (mmol m3), and bottom pH. Future conditions projected under SSP2-45 and SSP5-85. Data for present day conditions are based on Global Ocean Physics Reanalysis and Forecast and the Global Ocean Biogeochemistry

Analysis and Forecast provided by the Copernicus Marine Environment Monitoring Service (https://data.marine.copernicus. eu/products); future conditions are based on an Earth System Model ensemble (incl. ACCESS-ESM1-5; CanESM5; CESM2-WACCM; CNRM-ESM2-1; GFDL-ESM4; GISS-E2- 1-G; IPSL-CM6A-LR; MIROC-ES2L; MPI-ESM1- 2-LR; UKESM1- 0-LL) from CMIP6, downscaled to a spatial resolution of 0.05˚. [58] https://doi.org/10.1371/journal.pone.0316754.t002 PLOS ONE Indirect biodiversity conservation in the Gulf of St. Lawrence PLOS ONE | https://doi.org/10.1371/journal.pone.0316754 January 9, 2025 4 / 20