PURPOSE:
Trawl survey data used primarily for assessing the status of snow crab stocks in the southern Gulf of St. Lawrence.
DESCRIPTION:
Tow, catch, and biological information for snow crab and other species caught during the annual snow crab research vessel trawl survey in the southern Gulf of St. Lawrence. Currently, the survey uses a stratified random design that divides the area into 355 square grids, each measuring 12.7 km by 12.7 km. The survey area spans the majority of snow crab habitat in the southern Gulf, at depths ranging from 20 to 200 fathoms. Sampling stations are trawled during civil twilight hours using a Bigouden Nephrops bottom trawl net. The vessel operates at a target speed of 2 knots for a duration of 5 minutes, maintaining a warp-to-depth ratio of 3:1, with a maximum warp length of 575 fathoms.
PARAMETERS COLLECTED:
Snow crab: sex, carapace width, height of male crab claw, shell condition, gonad colour, egg colour, eggs remaining, and missing legs.
Other species: counts, and weights
Other: GPS coordinates; swept area; depth; temperature; CTD profile;
NOTES ON QUALITY CONTROL:
Data are checked for irregularities and errors.
SAMPLING METHODS:
Survey catches are sorted by species or taxonomic groups and measured directly on board. All snow crab are measured, while select fish species are measured only for a subset of survey stations.
USE LIMITATION:
To ensure scientific integrity and appropriate use of the data, we would encourage you to contact the data custodian.