This data is from the Newfoundland and Labrador Region Inshore Trap survey, specific to Snow Crab from 2018-25, with only successful sets included in the database. Details of annual survey coverage and an overview of the survey program can be found in Pantin et al. (2025).

This trap survey follows a depth-stratified random survey design, designated by type = 1 (Survey). Data were available from DFO inshore trap surveys in Fortune Bay, St. Mary’s Bay, Conception Bay, Trinity Bay, Bonavista Bay, Notre Dame Bay, White Bay, and infrequently along the Northeast Avalon Peninsula.

All surveys follow a depth-stratified survey design with set locations randomly distributed within each stratum, and stratum-specific set allocations weighted by area. All surveys utilize large-mesh (5.25”) and small-mesh (42 mm) traps intermittently placed within each ‘fleet’ of gear, with traps spaced approximately 45 m (i.e., 25 fathoms) apart. Each fleet includes six baited traps, with two additional end traps not baited. Squid (Illex spp.) hung on skivers is attached to the inner entry cone of each trap as bait, with approximately 2–3 pounds of squid on each skiver. Although soak times are intended to be standardized to 24–48 hours, weather and other factors can affect the surveys and soak times are ultimately variable.

Biological sampling is conducted at-sea from all traps at each station and is described in Pantin et al. (2025). Whole weights of Snow Crab are not always taken for every crab (e.g., in poor weather, missing limbs, carapace covered in biofouling) and those without measurements are denoted by an NA in the dataset. Analyses by the DFO NL Snow Crab group apply a length-weight relationship to determine weights, which is not in this dataset. Traps that caught zero Snow Crab are denoted in the dataset by a ‘number’ of 0.

References:

Pantin, J., D. Mullowney, K. Baker, K. Lefort, W. Coffey, F. Cyr, H. Munro, and Koen-Alonso, M. 2025. An Assessment of Newfoundland and Labrador Snow Crab (Chionoecetes opilio) in 2023. DFO. Can. Sci. Advis. Sec. Res. Doc. 2025/080. iv + 152 p.